Section 2 Radiation Therapy

**123**

**Chapter 7**

**Abstract**

**1. Introduction**

technique is called SBRT [1–4].

Techniques

Spinal Stereotactic Body

Radiotherapy (SBRT) Planning

*Jina Kim, Yunji Seol, Hong Seok Jang and Young-Nam Kang*

Stereotactic body radiotherapy (SBRT) delivers a highly conformal and hypofractionated radiation dose to a small target with minimal radiation applied to the surrounding areas. The spine is an ideal site for SBRT owing to its relative immobility, the potential clinical benefits of high-dose delivery to this area, and the presence of adjacent critical structures such as the spinal cord, esophagus, and bowel. However, with the potential for radiation myelopathy if the dose is delivered inaccurately or if the spinal cord dose limit is set too high, proper treatment planning techniques for SBRT are important. Intensity modulation techniques are useful for spinal SBRT because of a rapid dose falloff and spinal cord avoidance. In this

Stereotactic body radiotherapy (SBRT) was developed using the concepts of stereotactic radiosurgery (SRS). SRS was conceived by neurosurgeons and physicists in Sweden to allow the delivery of radiation to precise targets in the brain while minimizing injury to adjacent areas. The procedure delivers a high dose of radiation to the target accurately focused using multimodality imaging, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/CT (PET/CT). The total dose is divided into several smaller doses of radiation, administered on separate days of treatment, typically in a single fraction or a few fractions. SRS treats tumors by destroying and distorting the DNA of these cells, in the same way as other forms of radiotherapy. As a result, these cells lose their ability to reproduce and die. Applied to the treatment of body tumors, the

SBRT is also known as stereotactic ablative radiotherapy (SABR). SBRT ablates tumors by delivering precise and intensive radiation, guaranteeing minimal normal tissue complications. The characteristics of SBRT are summarized as follows: (1) a limited number of high dose-per-fraction treatments with a biologically equivalent dose (BED) of at least 75–100 as a minimum or even higher; (2) fields only slightly larger than gross tumor volume (GTV) with high accuracy even for moving targets, including the entire target with margins of 0.5–1.0 cm (i.e., exact delivery to tumor targets, sparing normal tissue); (3) dosimetry constructed to be very conformal,

chapter, various planning techniques will be discussed and reviewed.

**Keywords:** SBRT, spine, IMRT, IMAT, tomotherapy, CyberKnife

### **Chapter 7**

## Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques

*Jina Kim, Yunji Seol, Hong Seok Jang and Young-Nam Kang*

### **Abstract**

Stereotactic body radiotherapy (SBRT) delivers a highly conformal and hypofractionated radiation dose to a small target with minimal radiation applied to the surrounding areas. The spine is an ideal site for SBRT owing to its relative immobility, the potential clinical benefits of high-dose delivery to this area, and the presence of adjacent critical structures such as the spinal cord, esophagus, and bowel. However, with the potential for radiation myelopathy if the dose is delivered inaccurately or if the spinal cord dose limit is set too high, proper treatment planning techniques for SBRT are important. Intensity modulation techniques are useful for spinal SBRT because of a rapid dose falloff and spinal cord avoidance. In this chapter, various planning techniques will be discussed and reviewed.

**Keywords:** SBRT, spine, IMRT, IMAT, tomotherapy, CyberKnife

### **1. Introduction**

Stereotactic body radiotherapy (SBRT) was developed using the concepts of stereotactic radiosurgery (SRS). SRS was conceived by neurosurgeons and physicists in Sweden to allow the delivery of radiation to precise targets in the brain while minimizing injury to adjacent areas. The procedure delivers a high dose of radiation to the target accurately focused using multimodality imaging, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/CT (PET/CT). The total dose is divided into several smaller doses of radiation, administered on separate days of treatment, typically in a single fraction or a few fractions. SRS treats tumors by destroying and distorting the DNA of these cells, in the same way as other forms of radiotherapy. As a result, these cells lose their ability to reproduce and die. Applied to the treatment of body tumors, the technique is called SBRT [1–4].

SBRT is also known as stereotactic ablative radiotherapy (SABR). SBRT ablates tumors by delivering precise and intensive radiation, guaranteeing minimal normal tissue complications. The characteristics of SBRT are summarized as follows: (1) a limited number of high dose-per-fraction treatments with a biologically equivalent dose (BED) of at least 75–100 as a minimum or even higher; (2) fields only slightly larger than gross tumor volume (GTV) with high accuracy even for moving targets, including the entire target with margins of 0.5–1.0 cm (i.e., exact delivery to tumor targets, sparing normal tissue); (3) dosimetry constructed to be very conformal,

with sharp gradients from high- to low-dose areas; and (4) secure patient fixation during treatment and accurate duplication of patient position between simulation and treatment [2, 5–8].

Because of the high dose in a single fraction or fewer than five fractions, organs at risk (OARs) can be greatly affected by slight positional errors. Therefore, positional errors should be minimized. The margins of expansion can be reduced through the immobilization and control of respiratory motion of patients. Various commercial treatment delivery units in conjunction with the immobilization and respiratory motion control systems are available for the delivery of SBRT.

SBRT is currently both in use and being investigated for use in treating malignant or benign small- to medium-sized tumors in the body and at common disease sites, including the head and neck, lung, liver, abdomen, spine, and prostate. In particular, up to 70% of patients with malignancies are found to have skeletal involvement on postmortem examination, with the spine being the most common location [9]. For the treatment of spinal tumors, an extremely rapid dose falloff between the vertebral body and the spinal cord should be achieved [10, 11]. Implementation of correct beam-shaping and image-guided techniques has improved SBRT safety margins as well as accuracy and efficiency while accurately meeting 3D tumor contours. Spinal SBRT demands the highest accuracy in dose placement. In addition to patient fixation and multi-image guidance, a sophisticated treatment planning system that accurately models highly modulated small field beams is an indispensable factor in achieving high accuracy of radiation delivery.

To achieve this high accuracy, appropriate treatment planning technique should be used. Therefore, we will discuss various planning techniques for spinal SBRT in this chapter.

### **2. Spinal stereotactic body radiotherapy**

### **2.1 Spine**

The spine is a frequent site of metastases from primary cancer of the prostate, lung, breast, and kidney. After the lung and liver, the skeletal system is the most frequent site of metastases [12, 13], and 30% of all patients with cancer develop bone metastases [12, 14, 15]. In particular, bone metastasis occurs in 85% of patients with breast, prostate, and bronchial carcinoma [12, 16]. Approximately 50% of all bone metastases occur in the spinal cord. Of these, 60–80% are located in the thoracic spine, followed by 15–30% in the lumbar spine and less than 10% in the cervical spine [12, 13].

If left untreated, spinal metastases can cause axial pain, vertebral body fractures, radiculopathy, and the debilitating complications of metastatic epidural spinal cord compression (MESCC) [9]. The major complications of spinal metastases include neurologic dysfunction [12, 17, 18] and potential hypercalcemia, reduced activity, and bone fractures, resulting in a reduced quality of life [12, 16].

In general, primary spinal tumors are treated surgically, with the goal of maximal tumor removal. Numerous important blood vessels and adjacent organs surround the vertebrae. In particular, the spinal cord located in the vertebrae is a part of the central nervous system, which includes sensory and motor nerves. Complete resection of a tumor while preserving the nerve function of the spinal cord is difficult. In addition, vertebral instability due to tumor destruction or complete resection of the tumor must be considered, and fusion or fixation is often required for stability of the vertebrae. Depending on the malignancy of the tumor or the difficulty of complete resection, the patient may be treated with radiotherapy.

**125**

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

tissues irradiated because of the low biological effectiveness.

Traditional radiotherapy methods of treating spinal tumors use large field radiation to treat the entire pathological vertebra and to treat one or two vertebral bodies, generally above and below the disease. This practice prevents missing the tumor owing to the limitations of diagnostic imaging and localization. In addition, the irradiation field of this technique is large but safe in the volume of the normal

Large field radiation for spinal metastases has been the standard approach with

outcomes of ~30% complete pain response and ~70% any response. The main limitation of the dose prescribed by traditional radiation techniques was the spinal cord. Overdosing radiation to the spinal cord has the devastating consequence of radiation-induced myelopathy that can leave the patient paralyzed. In addition to radiation myelopathy, possible toxicities include vertebral compression fractures and pain flares. Owing to the limitations of technology to prevent overdosing, clinical trials of high-dose effects on spinal metastasis have not been possible [19].

To overcome the limitations of conventional radiotherapy for the spine, hypofractionated treatment has been proposed, to deliver a high dose per fraction (typically 10–20 Gy/fraction), in contrast to the conventional fractionated treatment (2 Gy/fraction). The cumulative BED is significantly higher than that received in conventional treatment. Accurate delivery is of utmost importance owing to the high fractional dose and a small number of fractions. The delivery of an ablative dose to the target and rapid falloff doses away from the target enables minimization of the treatment toxicity to a tolerable level [20, 21]. In addition, there are other characteristics that distinguish SBRT from conventional radiotherapy, such as the number of beams used for treatment, the frequent use of non-coplanar beam arrangements, small or no beam margins on the penumbra, and the use of inhomogeneous dose distributions and dose-painting techniques 'including IMRT'. All of these technology improvements result in the highly conformal dose distribution

Hypofractionated spinal SBRT has been shown to effectively and rapidly alleviate pain and improve neurological function in patients with or without epidural cord compression. SBRT allows minimal radiation exposure outside the target; the most significant problem associated with this procedure is related to spinal cord dose tolerance. Depending on the vertebral level of spinal metastasis, adjacent organs should be considered OARs. The tolerance of OARs to radiation from conventional fractionated radiotherapy is based on the entire organ or on a considerably large irradiated volume. SBRT delivers a highly conformal, hypofractionated radiation dose to a small target with minimal exposure of the surrounding areas to radiation [22]. A new radiotherapy technology that allows for intensity-modulated radiotherapy (IMRT) has emerged with spinal SBRT. IMRT is a technique designed to deliver a high biologically effective dose only to tumors within the vertebra for the purpose of tumor regression through permanent local control. The technique allows radiation beams to avoid the spinal cord, and even though a high dose is delivered to tumors, the dose received by the spinal cord is below the toxic threshold dose [23].

**Table 1** lists maximum dose limits to a point or volume within several critical organs recommended for SBRT in one fraction (refer to TG-101 for

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

**2.2 Radiotherapy for spinal tumors**

*2.2.2 Stereotactic body radiotherapy*

that characterizes the SBRT technique [2].

More details will be discussed in Section 3.

*2.2.1 Conventional method*

### **2.2 Radiotherapy for spinal tumors**

### *2.2.1 Conventional method*

*Ionizing and Non-ionizing Radiation*

and treatment [2, 5–8].

this chapter.

**2.1 Spine**

cervical spine [12, 13].

with sharp gradients from high- to low-dose areas; and (4) secure patient fixation during treatment and accurate duplication of patient position between simulation

at risk (OARs) can be greatly affected by slight positional errors. Therefore, positional errors should be minimized. The margins of expansion can be reduced through the immobilization and control of respiratory motion of patients. Various commercial treatment delivery units in conjunction with the immobilization and

respiratory motion control systems are available for the delivery of SBRT.

able factor in achieving high accuracy of radiation delivery.

**2. Spinal stereotactic body radiotherapy**

Because of the high dose in a single fraction or fewer than five fractions, organs

SBRT is currently both in use and being investigated for use in treating malignant or benign small- to medium-sized tumors in the body and at common disease sites, including the head and neck, lung, liver, abdomen, spine, and prostate. In particular, up to 70% of patients with malignancies are found to have skeletal involvement on postmortem examination, with the spine being the most common location [9]. For the treatment of spinal tumors, an extremely rapid dose falloff between the vertebral body and the spinal cord should be achieved [10, 11]. Implementation of correct beam-shaping and image-guided techniques has improved SBRT safety margins as well as accuracy and efficiency while accurately meeting 3D tumor contours. Spinal SBRT demands the highest accuracy in dose placement. In addition to patient fixation and multi-image guidance, a sophisticated treatment planning system that accurately models highly modulated small field beams is an indispens-

To achieve this high accuracy, appropriate treatment planning technique should be used. Therefore, we will discuss various planning techniques for spinal SBRT in

The spine is a frequent site of metastases from primary cancer of the prostate, lung, breast, and kidney. After the lung and liver, the skeletal system is the most frequent site of metastases [12, 13], and 30% of all patients with cancer develop bone metastases [12, 14, 15]. In particular, bone metastasis occurs in 85% of patients with breast, prostate, and bronchial carcinoma [12, 16]. Approximately 50% of all bone metastases occur in the spinal cord. Of these, 60–80% are located in the thoracic spine, followed by 15–30% in the lumbar spine and less than 10% in the

If left untreated, spinal metastases can cause axial pain, vertebral body fractures, radiculopathy, and the debilitating complications of metastatic epidural spinal cord compression (MESCC) [9]. The major complications of spinal metastases include neurologic dysfunction [12, 17, 18] and potential hypercalcemia, reduced

In general, primary spinal tumors are treated surgically, with the goal of maximal tumor removal. Numerous important blood vessels and adjacent organs surround the vertebrae. In particular, the spinal cord located in the vertebrae is a part of the central nervous system, which includes sensory and motor nerves. Complete resection of a tumor while preserving the nerve function of the spinal cord is difficult. In addition, vertebral instability due to tumor destruction or complete resection of the tumor must be considered, and fusion or fixation is often required for stability of the vertebrae. Depending on the malignancy of the tumor or the difficulty of complete resection, the patient may be treated with radiotherapy.

activity, and bone fractures, resulting in a reduced quality of life [12, 16].

**124**

Traditional radiotherapy methods of treating spinal tumors use large field radiation to treat the entire pathological vertebra and to treat one or two vertebral bodies, generally above and below the disease. This practice prevents missing the tumor owing to the limitations of diagnostic imaging and localization. In addition, the irradiation field of this technique is large but safe in the volume of the normal tissues irradiated because of the low biological effectiveness.

Large field radiation for spinal metastases has been the standard approach with outcomes of ~30% complete pain response and ~70% any response. The main limitation of the dose prescribed by traditional radiation techniques was the spinal cord. Overdosing radiation to the spinal cord has the devastating consequence of radiation-induced myelopathy that can leave the patient paralyzed. In addition to radiation myelopathy, possible toxicities include vertebral compression fractures and pain flares. Owing to the limitations of technology to prevent overdosing, clinical trials of high-dose effects on spinal metastasis have not been possible [19].

### *2.2.2 Stereotactic body radiotherapy*

To overcome the limitations of conventional radiotherapy for the spine, hypofractionated treatment has been proposed, to deliver a high dose per fraction (typically 10–20 Gy/fraction), in contrast to the conventional fractionated treatment (2 Gy/fraction). The cumulative BED is significantly higher than that received in conventional treatment. Accurate delivery is of utmost importance owing to the high fractional dose and a small number of fractions. The delivery of an ablative dose to the target and rapid falloff doses away from the target enables minimization of the treatment toxicity to a tolerable level [20, 21]. In addition, there are other characteristics that distinguish SBRT from conventional radiotherapy, such as the number of beams used for treatment, the frequent use of non-coplanar beam arrangements, small or no beam margins on the penumbra, and the use of inhomogeneous dose distributions and dose-painting techniques 'including IMRT'. All of these technology improvements result in the highly conformal dose distribution that characterizes the SBRT technique [2].

Hypofractionated spinal SBRT has been shown to effectively and rapidly alleviate pain and improve neurological function in patients with or without epidural cord compression. SBRT allows minimal radiation exposure outside the target; the most significant problem associated with this procedure is related to spinal cord dose tolerance. Depending on the vertebral level of spinal metastasis, adjacent organs should be considered OARs. The tolerance of OARs to radiation from conventional fractionated radiotherapy is based on the entire organ or on a considerably large irradiated volume. SBRT delivers a highly conformal, hypofractionated radiation dose to a small target with minimal exposure of the surrounding areas to radiation [22].

A new radiotherapy technology that allows for intensity-modulated radiotherapy (IMRT) has emerged with spinal SBRT. IMRT is a technique designed to deliver a high biologically effective dose only to tumors within the vertebra for the purpose of tumor regression through permanent local control. The technique allows radiation beams to avoid the spinal cord, and even though a high dose is delivered to tumors, the dose received by the spinal cord is below the toxic threshold dose [23]. More details will be discussed in Section 3.

**Table 1** lists maximum dose limits to a point or volume within several critical organs recommended for SBRT in one fraction (refer to TG-101 for


### **Table 1.**

*One fraction dose constraints of several critical organs from RTOG 0613 [24].*

multiple-fraction dose constraints [2]). The recommended dose constraints are shown in max critical volume and the maximum dose to the given volume for each organ. These limitations have been determined based on the widely accepted radiosurgery norms currently in practice. Regardless of these limitations, the participating centers are encouraged to adhere to the prudent treatment planning principle to avoid unnecessary radiation exposure to critical normal structures [24].

**127**

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

Various commercial treatment delivery units can be used to deliver SBRT [1, 5, 7], as shown in **Figure 1**. They all have the capability of image-guided radiotherapy, enabling tumor or target localization prior to treatment delivery and allowing treatment setup uncertainty to be significantly reduced. All delivery units, with the exception of proton therapy, used as photon-based SBRT, are linear accelerators (LINACs). There are several types of image-guidance equipment: 2D imaging types, including room-mounted or gantry-mounted orthogonal kilovoltage (kV) radiographs and fluoroscopy, and 3D imaging types including kV or megavoltage (MV)

*Commercial treatment delivery units. From left to right are versa HD (Elekta AB), Radixact (Accuray Inc.),* 

In addition to general LINACs, there are many types of treatment systems. The CyberKnife (CK, Accuray Inc., Sunnyvale, CA, USA) unit has a six-axis robotic manipulator that enables delivery of the beam to the target from many different directions in order to minimize radiation exposure to nearby organs. A pair of orthogonally positioned imaging systems enables monitoring of the target motion, with automatic correction. CK is a commonly used modality for SBRT owing to its highly conformal dose distributions, steep gradient, and near real-time imageguidance system. The helical tomotherapy (HT, Accuray) unit is a special device performing continuous 360° rotations using a binary multi-leaf collimator (MLC),

Each treatment delivery system has strengths and weaknesses. An appropriate treatment delivery system and corresponding optimal planning technique should be

SBRT is a high-precision radiotherapy technique that utilizes the high doses of radiation in a single fraction or a few fractions, as mentioned in the above sections. In principle, three-dimensional conformal radiotherapy (3D-CRT) planning can be applied to SBRT. When the beams at multiple angles are concentrated at the center of small lesions, a high-dose heterogeneity that contributes to a steep dose gradient

with the treatment couch moving continuously during the treatment [1].

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

*2.2.3 SBRT delivery systems*

*and CyberKnife M6 (Accuray Inc.).*

**Figure 1.**

cone-beam CT (CBCT) and CT-on-rails in room.

used for successful and safe treatment.

**3. SBRT planning techniques**

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques DOI: http://dx.doi.org/10.5772/intechopen.83515*

### **Figure 1.**

*Ionizing and Non-ionizing Radiation*

Ipsilateral brachial

Renal hilum/vascular

Renal cortex (right and left)

*\*Avoid circumferential irradiation.*

trunk

**Table 1.**

plexus

**Serial tissue Max critical volume Max dose in critical** 

Spinal cord <0.035 cc 14 Gy Myelitis <0.35 cc 10 Gy <1.2 cc (SBRT only) 7 Gy (SBRT only) Cauda equina <0.035 cc 16 Gy Neuritis <5 cc 14 Gy Sacral plexus <0.035 cc 18 Gy Neuropathy <5 cc 14.4 Gy Esophagus\* <0.035 cc 16 Gy Stenosis/fistula <5 cc 11.9 Gy

<3 cc 14 Gy Heart/pericardium <0.035 cc 22 Gy Pericarditis <15 cc 16 Gy Great vessels\* <0.035 cc 37 Gy Aneurysm <10 cc 31 Gy Trachea\* and larynx <0.035 cc 20.2 Gy Stenosis/fistula <4 cc 10.5 Gy Skin <0.035 cc 26 Gy Ulceration <10 cc 23 Gy Stomach <0.035 cc 16 Gy Ulceration/fistula <10 cc 11.2 Gy Duodenum\* <0.035 cc 16 Gy Ulceration <5 cc 11.2 Gy Jejunum/ileum\* <0.035 cc 15.4 Gy Enteritis/obstruction <5 cc 11.9 Gy Colon\* <0.035 cc 18.4 Gy Colitis/fistula <20 cc 14.3 Gy Rectum\* <0.035 cc 18.4 Gy Proctitis/fistula <20 cc 14.3 Gy

**volume (Gy)**

<0.035 cc 17.5 Gy Neuropathy

<2/3 volume 10.6 Gy Malignant hypertension

200 cc 8.4 Gy Basic renal function

**End point (**≥**Grade 3)**

**volume (Gy)**

**End point (**≥ **Grade 3)**

**126**

multiple-fraction dose constraints [2]). The recommended dose constraints are shown in max critical volume and the maximum dose to the given volume for each organ. These limitations have been determined based on the widely accepted radiosurgery norms currently in practice. Regardless of these limitations, the participating centers are encouraged to adhere to the prudent treatment planning principle to

Lung (right and left) 1000 cc 7.4 Gy Pneumonitis

avoid unnecessary radiation exposure to critical normal structures [24].

**Parallel tissue Critical volume (cc) Max dose in critical** 

*One fraction dose constraints of several critical organs from RTOG 0613 [24].*

*Commercial treatment delivery units. From left to right are versa HD (Elekta AB), Radixact (Accuray Inc.), and CyberKnife M6 (Accuray Inc.).*

### *2.2.3 SBRT delivery systems*

Various commercial treatment delivery units can be used to deliver SBRT [1, 5, 7], as shown in **Figure 1**. They all have the capability of image-guided radiotherapy, enabling tumor or target localization prior to treatment delivery and allowing treatment setup uncertainty to be significantly reduced. All delivery units, with the exception of proton therapy, used as photon-based SBRT, are linear accelerators (LINACs). There are several types of image-guidance equipment: 2D imaging types, including room-mounted or gantry-mounted orthogonal kilovoltage (kV) radiographs and fluoroscopy, and 3D imaging types including kV or megavoltage (MV) cone-beam CT (CBCT) and CT-on-rails in room.

In addition to general LINACs, there are many types of treatment systems. The CyberKnife (CK, Accuray Inc., Sunnyvale, CA, USA) unit has a six-axis robotic manipulator that enables delivery of the beam to the target from many different directions in order to minimize radiation exposure to nearby organs. A pair of orthogonally positioned imaging systems enables monitoring of the target motion, with automatic correction. CK is a commonly used modality for SBRT owing to its highly conformal dose distributions, steep gradient, and near real-time imageguidance system. The helical tomotherapy (HT, Accuray) unit is a special device performing continuous 360° rotations using a binary multi-leaf collimator (MLC), with the treatment couch moving continuously during the treatment [1].

Each treatment delivery system has strengths and weaknesses. An appropriate treatment delivery system and corresponding optimal planning technique should be used for successful and safe treatment.

### **3. SBRT planning techniques**

SBRT is a high-precision radiotherapy technique that utilizes the high doses of radiation in a single fraction or a few fractions, as mentioned in the above sections. In principle, three-dimensional conformal radiotherapy (3D-CRT) planning can be applied to SBRT. When the beams at multiple angles are concentrated at the center of small lesions, a high-dose heterogeneity that contributes to a steep dose gradient

at the target edge appears and may be desirable in terms of normal tissue sparing and dose escalation to the GTV [1].

To treat a spinal tumor, conventionally fractionated 3D-CRT modifies the beam shape to match the projection of target volume at each gantry angle using an MLC. The accuracy of the shape of the beam projected onto the target depends on the width of leaves. MLC leaf widths of 2.5–10 mm have been reported for use in SBRT planning [25, 26].

However, delivery to the target is limited by tolerance of normal tissues, particularly the spinal cord, so it is necessary to irradiate the target with lower dose. In suboptimal cases, several side effects can occur, such as paraplegia, pain, increased steroid use, and reduced survival rate.

### **3.1 Intensity-modulated radiation treatment**

The development of IMRT was a major improvement over 3D-CRT for SBRT [27]. IMRT allows for the radiation dose to conform more precisely to the shape of the tumor by modulating the intensity of the radiation beam and allows higher radiation doses to be focused to regions within the tumor, sparing the surrounding normal critical structures. In particular, when treating spinal tumors, intensity modulation allows production of a concave-shaped dose distribution with the exception of the spinal cord.

The IMRT technique uses computerized inverse planning. Conformal radiotherapy is forward planning and depends on the skills of the treatment planner to determine the number, shape, and orientation of the beams. Inverse planning, in contrast, specifies the plan outcome in terms of the tumor dose and normal structure dose limits. The computer system then adjusts the beam intensities to identify a configuration best matched to the desired plan [28].

During the procedure, each beam is divided into several beam elements (beamlets) of a few millimeters, and the relative weight is optimized so that the desired dose distribution appears. The optimization process involves inverse planning in which beamlet weights or intensities are adjusted to satisfy predefined dose criteria for the composite plan. When optimization is complete, an optimized fluence map generates a sequence of MLC leaves for each beam. The field at one gantry angle is subdivided into a set of subfields irradiated at a uniform beam intensity level. The subfields are shaped by the MLC, and the intensity-modulated field is obtained by summing several subfields.

The two most common methods of IMRT delivery are segmental (step-andshoot) and dynamic (sliding window). The difference between the two is the motion of MLC at a given gantry angle. In segmental MLC delivery, the beam is turned off while the leaves move until the next subfield is prepared. The advantage of the segmental MLC method is that it is easy to plan and no additional dose can occur while the MLC is moving to create the next subfield. On the other hand, the dose delivery is slow owing to the delay in turning the beam on and off, resulting in an increase in treatment time. In the dynamic MLC delivery, the MLC leaves are moving during irradiation. Each pair of leaves sweeps across target volumes under computer control. Dynamic MLC delivery offers better dose homogeneity for target volume and shorter treatment time in comparison to the segmental MLC; however, the larger total irradiated dose is a disadvantage.

Compared to 3D-CRT, the dose distribution can be made even more sophisticated because target coverage and avoidance of critical structures located adjacent to the target volume are better. The more sophisticated implementation of SBRT has become possible with the IMRT technique. The technique mentioned in this section (Section 3.1) was the IMRT technique with a fixed gantry, and IMRT with a rotating gantry will be discussed in the following section (Section 3.2).

**129**

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

Intensity-modulated arc therapy (IMAT) is a combined technique of IMRT and rotational treatment. When performed for a C-shaped target with a sensitive structure in the concavity of the "C," like a spinal tumor, the rotational treatment has a dosimetric advantage. The result of simulation that supports this is that when all the planning parameters except the beam angle number are constant, the dose becomes more homogeneous in the tumor and decreased in the critical structures as

IMAT uses rotational cone beams of varying aperture shapes and varying dose weightings to achieve intensity modulation. However, the speed of rotation cannot have frequent and drastic variations owing to the weight of the LINAC gantry; therefore, the variations in dose weighting are primarily achieved through varying the machine dose weight. MLC moves dynamically to shape each subfield while the gantry is rotating and the beam is on continuously [30]. Arcs are approximated as multiple-shaped fields in a regular angular interval. One subfield is delivered at each arc. The next new arc is started to deliver the next subfield and so on until all the planned arcs and their subfields have been delivered. That is, overlapping arcs

To create more effective treatment plans, various techniques have been purposed

within IMAT. Volumetric-modulated arc therapy (VMAT) and modulated arc therapy (mARC) are examples of such techniques. VMAT is a single or multi-arc form of IMRT technique that changes the dose rate and gantry speed while the gantry is rotating. Currently there are several VMAT systems available under various names (RapidArc, Varian Medical Systems, Palo Alto, CA, USA; SmartArc, Philips Radiation Oncology Systems, Fitchburg, WI, USA; and Elekta VMAT, Elekta, Stockholm, Sweden) [31]. The mARC technique as an alternative to VMAT is a rotational IMRT irradiation with burst mode delivery. Both the dose rate and gantry speed are modulated to allow for delivery of the correct dose per IMRT segment, and an MLC velocity servo is required to continuously adjust the leaf velocity to

The technique is similar to HT, which is an IMRT technique that rotates in a helical form and will be discussed in Section 3.3. As compared with HT, IMAT has certain advantages: (1) IMAT eliminates the need for transferring the patient during treatment and avoids abutment issues as seen with serial HT, (2) IMAT retains the ability to use non-coplanar beams and arcs, and (3) IMAT uses a conventional LINAC; thus, complex rotational IMRT treatments and simple palliative treatments

The main advantages of rotational therapy compared to fixed-gantry IMRT are improved conformity of the dose distribution in the high-dose regions, as well as possible reduction of the treatment time. The short treatment time can lead to improved patient comfort and reduce the risk of movement. Moreover, shorter treatment times can be biologically beneficial. Radiation survival is not only a function of the total dose delivered but also depends on the duration of radiation delivery [33, 34]. IMAT offers the efficient use of monitor units (MUs). The number of MUs per treatment is correlated with the amount of scatter dose and leakage radiation, which could be important in view of the induction of secondary malignancies [35]. The decrease in MUs achieved with IMAT partly addresses this issue,

However, the complex nature of IMAT planning has been one of the primary barriers to routine clinical implementation. From one angle to the next in each VMAT arc, leaf motion between adjacent angles is limited by leaf travel speed and gantry rotation speed. Therefore, the technique has disadvantages such as difficulty and complexity of planning.

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

**3.2 Intensity-modulated arc therapy**

the number of angles increased [29].

create intensity modulation.

facilitate accurate, and timely, leaf positioning [32].

can be delivered with the same treatment unit [30].

which is one of the major concerns with IMRT [36].

### **3.2 Intensity-modulated arc therapy**

*Ionizing and Non-ionizing Radiation*

and dose escalation to the GTV [1].

steroid use, and reduced survival rate.

the exception of the spinal cord.

**3.1 Intensity-modulated radiation treatment**

configuration best matched to the desired plan [28].

the larger total irradiated dose is a disadvantage.

gantry will be discussed in the following section (Section 3.2).

SBRT planning [25, 26].

at the target edge appears and may be desirable in terms of normal tissue sparing

To treat a spinal tumor, conventionally fractionated 3D-CRT modifies the beam shape to match the projection of target volume at each gantry angle using an MLC. The accuracy of the shape of the beam projected onto the target depends on the width of leaves. MLC leaf widths of 2.5–10 mm have been reported for use in

However, delivery to the target is limited by tolerance of normal tissues, particularly the spinal cord, so it is necessary to irradiate the target with lower dose. In suboptimal cases, several side effects can occur, such as paraplegia, pain, increased

The development of IMRT was a major improvement over 3D-CRT for SBRT [27]. IMRT allows for the radiation dose to conform more precisely to the shape of the tumor by modulating the intensity of the radiation beam and allows higher radiation doses to be focused to regions within the tumor, sparing the surrounding normal critical structures. In particular, when treating spinal tumors, intensity modulation allows production of a concave-shaped dose distribution with

The IMRT technique uses computerized inverse planning. Conformal radiotherapy is forward planning and depends on the skills of the treatment planner to determine the number, shape, and orientation of the beams. Inverse planning, in contrast, specifies the plan outcome in terms of the tumor dose and normal structure dose limits. The computer system then adjusts the beam intensities to identify a

During the procedure, each beam is divided into several beam elements (beamlets) of a few millimeters, and the relative weight is optimized so that the desired dose distribution appears. The optimization process involves inverse planning in which beamlet weights or intensities are adjusted to satisfy predefined dose criteria for the composite plan. When optimization is complete, an optimized fluence map generates a sequence of MLC leaves for each beam. The field at one gantry angle is subdivided into a set of subfields irradiated at a uniform beam intensity level. The subfields are shaped by the MLC, and the intensity-modulated field is obtained by summing several subfields. The two most common methods of IMRT delivery are segmental (step-andshoot) and dynamic (sliding window). The difference between the two is the motion of MLC at a given gantry angle. In segmental MLC delivery, the beam is turned off while the leaves move until the next subfield is prepared. The advantage of the segmental MLC method is that it is easy to plan and no additional dose can occur while the MLC is moving to create the next subfield. On the other hand, the dose delivery is slow owing to the delay in turning the beam on and off, resulting in an increase in treatment time. In the dynamic MLC delivery, the MLC leaves are moving during irradiation. Each pair of leaves sweeps across target volumes under computer control. Dynamic MLC delivery offers better dose homogeneity for target volume and shorter treatment time in comparison to the segmental MLC; however,

Compared to 3D-CRT, the dose distribution can be made even more sophisticated because target coverage and avoidance of critical structures located adjacent to the target volume are better. The more sophisticated implementation of SBRT has become possible with the IMRT technique. The technique mentioned in this section (Section 3.1) was the IMRT technique with a fixed gantry, and IMRT with a rotating

**128**

Intensity-modulated arc therapy (IMAT) is a combined technique of IMRT and rotational treatment. When performed for a C-shaped target with a sensitive structure in the concavity of the "C," like a spinal tumor, the rotational treatment has a dosimetric advantage. The result of simulation that supports this is that when all the planning parameters except the beam angle number are constant, the dose becomes more homogeneous in the tumor and decreased in the critical structures as the number of angles increased [29].

IMAT uses rotational cone beams of varying aperture shapes and varying dose weightings to achieve intensity modulation. However, the speed of rotation cannot have frequent and drastic variations owing to the weight of the LINAC gantry; therefore, the variations in dose weighting are primarily achieved through varying the machine dose weight. MLC moves dynamically to shape each subfield while the gantry is rotating and the beam is on continuously [30]. Arcs are approximated as multiple-shaped fields in a regular angular interval. One subfield is delivered at each arc. The next new arc is started to deliver the next subfield and so on until all the planned arcs and their subfields have been delivered. That is, overlapping arcs create intensity modulation.

To create more effective treatment plans, various techniques have been purposed within IMAT. Volumetric-modulated arc therapy (VMAT) and modulated arc therapy (mARC) are examples of such techniques. VMAT is a single or multi-arc form of IMRT technique that changes the dose rate and gantry speed while the gantry is rotating. Currently there are several VMAT systems available under various names (RapidArc, Varian Medical Systems, Palo Alto, CA, USA; SmartArc, Philips Radiation Oncology Systems, Fitchburg, WI, USA; and Elekta VMAT, Elekta, Stockholm, Sweden) [31]. The mARC technique as an alternative to VMAT is a rotational IMRT irradiation with burst mode delivery. Both the dose rate and gantry speed are modulated to allow for delivery of the correct dose per IMRT segment, and an MLC velocity servo is required to continuously adjust the leaf velocity to facilitate accurate, and timely, leaf positioning [32].

The technique is similar to HT, which is an IMRT technique that rotates in a helical form and will be discussed in Section 3.3. As compared with HT, IMAT has certain advantages: (1) IMAT eliminates the need for transferring the patient during treatment and avoids abutment issues as seen with serial HT, (2) IMAT retains the ability to use non-coplanar beams and arcs, and (3) IMAT uses a conventional LINAC; thus, complex rotational IMRT treatments and simple palliative treatments can be delivered with the same treatment unit [30].

The main advantages of rotational therapy compared to fixed-gantry IMRT are improved conformity of the dose distribution in the high-dose regions, as well as possible reduction of the treatment time. The short treatment time can lead to improved patient comfort and reduce the risk of movement. Moreover, shorter treatment times can be biologically beneficial. Radiation survival is not only a function of the total dose delivered but also depends on the duration of radiation delivery [33, 34]. IMAT offers the efficient use of monitor units (MUs). The number of MUs per treatment is correlated with the amount of scatter dose and leakage radiation, which could be important in view of the induction of secondary malignancies [35]. The decrease in MUs achieved with IMAT partly addresses this issue, which is one of the major concerns with IMRT [36].

However, the complex nature of IMAT planning has been one of the primary barriers to routine clinical implementation. From one angle to the next in each VMAT arc, leaf motion between adjacent angles is limited by leaf travel speed and gantry rotation speed. Therefore, the technique has disadvantages such as difficulty and complexity of planning.

### **3.3 Helical tomotherapy**

HT is a radiotherapy modality that combines helical CT scanning with an MV linear accelerator. A 6 MV LINAC rotates on a ring gantry at a source-axis distance (SAD) of 85 cm, and the beam passes through a primary collimator into a fan-beam shape. During treatment, the ring gantry continuously rotates, while the couch is continuously translated through the rotating beam plane. The dose is thus delivered in a helical fashion. The ring gantry also contains a detector system that is mounted opposite the accelerator and is used to collect data for megavoltage CT (MVCT) acquisition. A beam stopper is used to reduce room-shielding requirements [37].

The MVCT in HT is used as a tool to enhance image-guided daily treatment setup and positioning of the patient. Because SBRT usually requires a longer treatment period owing to the use of high-dose hypofraction, the patient must be fixed in place to limit the patient's movement during treatment. However, patients with vertebral metastases, in particular, often move involuntarily during treatment owing to back pain that cannot be controlled. Therefore, it is important to ensure the accuracy of high-dose delivery and to avoid side effects of OARs on intrafractional movement. A daily MVCT image scan is generated prior to treatment to ensure accurate delivery of each treatment according to the patient's anatomy on a particular day. This MVCT is integrated with the kilovoltage CT (kVCT) imaging plan to provide a reference for patient setup and positioning [38].

The fan-beam has an extension of 40 cm in the lateral direction and smaller or equal to 5 cm (typically 1.0, 2.5, and 5.0 cm) in the longitudinal direction at the isocenter. With the use of a compressed air-driven multi-leaf (64 leaves) binary collimator (MLC), radiation beams are shaped, and their intensities are modulated. The leaves are mounted on two opposite blocks, and each individual leaf is driven from open to closed state. The intensity modulation is achieved by controlling the length of time each leaf is open. Each leaf has a width of 6.25 mm (40 cm divided by 64 leaves) and rapid transitioning (about 20 ms); thus it can produce a sufficiently accurate shape even within a short rotation period. Therefore, HT offers a very useful treatment modality of spinal SBRT by implementing image-guided radiation therapy (IGRT) and IMRT techniques.

For the treatment planning of each rotation, a rotation is divided into 51 projections (360°/7° = 51). For each projection, each MLC leaf has a unique opening time as shown in **Figure 2** [39]. Unlike the usual LINAC radiotherapy, there are additional parameters: slice width, pitch factor, and modulation factor. These parameters influence both treatment time and quality of the treatment plan.

Slice width (or field width) is the longitudinal extent (i.e., in the y-direction) of the treatment field. For planning purposes, a nominal 1.0, 2.5, or 5.0 cm is selected. Pitch is defined as distance traveled by the couch per gantry rotation, divided by the slice width. With a lower pitch value, there is greater overlap between spirals. This factor influences the treatment time. Modulation factor is defined as the maximum leaf opening time divided by the average opening time of all leaves. This value can range from 1.0 to 10 (typically using from 1.5 to 3.5). For a complex treatment requiring a lot of MLC motion, a high modulation factor is selected.

One of the most important differences between the HT system and other radiotherapy systems is that the HT system does not have a flattening filter. The main advantages of an absent flattening filter are an increased dose rate, reduced scatter, reduced leakage, and reduced out-of-field doses [40, 41]. The main reason for allowing the nonuniform profile is that HT is a dedicated IMRT system, without the need for a flat dose profile. If it is still desired, the MLC can be used to modulate the treatment field to produce a flat dose distribution [42].

**131**

target coverage.

**Figure 2.**

**3.4 CyberKnife**

radiographs generated by CT simulation [43].

treatment without the need to move the patient.

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

In treating spinal tumors, the major requirement is minimization of the dose to the spinal cord. The dose gradient should be increased to improve the conformity while allowing increased heterogeneity in the tumor volume coverage. In addition, the slice width and pitch parameters are considered to increase cord avoidance and

*Illustration of the helical tomotherapy delivery. Copyright © Journal of Medical Physics.*

CK is one of the representative delivery units of SBRT. As mentioned briefly in the above section, CK has uniquely different features compared with the common medical LINACs. The compact LINAC mounted on a computer-controlled six-axis robotic manipulator delivers radiation beams anywhere in the body with submillimeter accuracy. The integrated orthogonally positioned kV X-ray imaging system is utilized to monitor the patient position throughout the course of radiotherapy. Patients are positioned automatically or manually by a therapist by matching fiducial markers or bony anatomy from X-ray images to digital reconstructed

The robotic manipulator with six degrees of freedom can deliver the beam anywhere in space. Accordingly, the beam position and orientation can be adjusted by the robot to accommodate changes in target position and orientation during

The beam field size is controlled through various collimation types: 12 fixed cone collimators or an Iris variable collimator (Accuray) consisting of 12 tungsten leaves that produce beam diameters ranging from 5 to 60 mm (defined at 800 mm distance from the X-ray source) [44]. Furthermore, to compensate for the limit caused by the fixed field size, an MLC has recently been introduced for the CK [45]. The new MLC system consists of 41 leaf pairs, each with a width of 2.5 mm. The maximum field size is 12 × 10.25 cm. This new system allows the fields to be shaped matching the tumor shape and allows reduction of treatment time. In particular, using the MLC offers a dosimetric advantage for targets near OARs, as shown in **Figure 3** [46].

The unit delivers multiple isocentric or non-isocentric photon beams to a desired

target from many different angles through a robotic arm, as well as optic image guidance for motion management. The isocentric treatment planning is similar to

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques DOI: http://dx.doi.org/10.5772/intechopen.83515*

### **Figure 2.**

*Ionizing and Non-ionizing Radiation*

HT is a radiotherapy modality that combines helical CT scanning with an MV linear accelerator. A 6 MV LINAC rotates on a ring gantry at a source-axis distance (SAD) of 85 cm, and the beam passes through a primary collimator into a fan-beam shape. During treatment, the ring gantry continuously rotates, while the couch is continuously translated through the rotating beam plane. The dose is thus delivered in a helical fashion. The ring gantry also contains a detector system that is mounted opposite the accelerator and is used to collect data for megavoltage CT (MVCT) acquisition. A beam stopper is used to reduce room-shielding

The MVCT in HT is used as a tool to enhance image-guided daily treatment setup and positioning of the patient. Because SBRT usually requires a longer treatment period owing to the use of high-dose hypofraction, the patient must be fixed in place to limit the patient's movement during treatment. However, patients with vertebral metastases, in particular, often move involuntarily during treatment owing to back pain that cannot be controlled. Therefore, it is important to ensure the accuracy of high-dose delivery and to avoid side effects of OARs on intrafractional movement. A daily MVCT image scan is generated prior to treatment to ensure accurate delivery of each treatment according to the patient's anatomy on a particular day. This MVCT is integrated with the kilovoltage CT (kVCT) imaging

The fan-beam has an extension of 40 cm in the lateral direction and smaller or equal to 5 cm (typically 1.0, 2.5, and 5.0 cm) in the longitudinal direction at the isocenter. With the use of a compressed air-driven multi-leaf (64 leaves) binary collimator (MLC), radiation beams are shaped, and their intensities are modulated. The leaves are mounted on two opposite blocks, and each individual leaf is driven from open to closed state. The intensity modulation is achieved by controlling the length of time each leaf is open. Each leaf has a width of 6.25 mm (40 cm divided by 64 leaves) and rapid transitioning (about 20 ms); thus it can produce a sufficiently accurate shape even within a short rotation period. Therefore, HT offers a very useful treatment modality of spinal SBRT by implementing image-guided radiation

For the treatment planning of each rotation, a rotation is divided into 51 projections (360°/7° = 51). For each projection, each MLC leaf has a unique opening time as shown in **Figure 2** [39]. Unlike the usual LINAC radiotherapy, there are additional parameters: slice width, pitch factor, and modulation factor. These param-

Slice width (or field width) is the longitudinal extent (i.e., in the y-direction) of the treatment field. For planning purposes, a nominal 1.0, 2.5, or 5.0 cm is selected. Pitch is defined as distance traveled by the couch per gantry rotation, divided by the slice width. With a lower pitch value, there is greater overlap between spirals. This factor influences the treatment time. Modulation factor is defined as the maximum leaf opening time divided by the average opening time of all leaves. This value can range from 1.0 to 10 (typically using from 1.5 to 3.5). For a complex treatment

eters influence both treatment time and quality of the treatment plan.

requiring a lot of MLC motion, a high modulation factor is selected.

the treatment field to produce a flat dose distribution [42].

One of the most important differences between the HT system and other radiotherapy systems is that the HT system does not have a flattening filter. The main advantages of an absent flattening filter are an increased dose rate, reduced scatter, reduced leakage, and reduced out-of-field doses [40, 41]. The main reason for allowing the nonuniform profile is that HT is a dedicated IMRT system, without the need for a flat dose profile. If it is still desired, the MLC can be used to modulate

plan to provide a reference for patient setup and positioning [38].

therapy (IGRT) and IMRT techniques.

**3.3 Helical tomotherapy**

requirements [37].

**130**

*Illustration of the helical tomotherapy delivery. Copyright © Journal of Medical Physics.*

In treating spinal tumors, the major requirement is minimization of the dose to the spinal cord. The dose gradient should be increased to improve the conformity while allowing increased heterogeneity in the tumor volume coverage. In addition, the slice width and pitch parameters are considered to increase cord avoidance and target coverage.

### **3.4 CyberKnife**

CK is one of the representative delivery units of SBRT. As mentioned briefly in the above section, CK has uniquely different features compared with the common medical LINACs. The compact LINAC mounted on a computer-controlled six-axis robotic manipulator delivers radiation beams anywhere in the body with submillimeter accuracy. The integrated orthogonally positioned kV X-ray imaging system is utilized to monitor the patient position throughout the course of radiotherapy. Patients are positioned automatically or manually by a therapist by matching fiducial markers or bony anatomy from X-ray images to digital reconstructed radiographs generated by CT simulation [43].

The robotic manipulator with six degrees of freedom can deliver the beam anywhere in space. Accordingly, the beam position and orientation can be adjusted by the robot to accommodate changes in target position and orientation during treatment without the need to move the patient.

The beam field size is controlled through various collimation types: 12 fixed cone collimators or an Iris variable collimator (Accuray) consisting of 12 tungsten leaves that produce beam diameters ranging from 5 to 60 mm (defined at 800 mm distance from the X-ray source) [44]. Furthermore, to compensate for the limit caused by the fixed field size, an MLC has recently been introduced for the CK [45]. The new MLC system consists of 41 leaf pairs, each with a width of 2.5 mm. The maximum field size is 12 × 10.25 cm. This new system allows the fields to be shaped matching the tumor shape and allows reduction of treatment time. In particular, using the MLC offers a dosimetric advantage for targets near OARs, as shown in **Figure 3** [46].

The unit delivers multiple isocentric or non-isocentric photon beams to a desired target from many different angles through a robotic arm, as well as optic image guidance for motion management. The isocentric treatment planning is similar to

**Figure 3.**

*Dose-volume parameters in circular collimator and multi-leaf collimator (MLC) plans for 1–7 cm brain target volumes. (White bars indicate multi-leaf collimator (MLC) and gray indicate circular collimator.) Copyright © 2017, Oxford University Press.*

that of the Gammaknife (Elekta) and conventional LINACs, which have a fixed mechanical center of the gantry and collimator. The location of the isocenter is not limited, providing a great advantage over many other delivery units. However, this advantage can be overcome by using inverse planning; the final target dose distributions can be manipulated to a certain level by modifying the order of the targets as well as the contours and dose limits assigned to the target and critical organs.

In non-isocentric treatment planning, radiation beams are delivered to a specific portion of the tumor without couch repositioning. This technique makes the highdose isodose lines match the target shape and avoid nearby critical organs. Therefore, non-isocentric planning is very useful for treatment of irregularly shaped targets. CK, which is available with both plans, is advantageous for combining the rapid dose falloff of isocentric plans with the dose conformity of non-isocentric plans [1].

### **3.5 Planning considerations**

In spinal SBRT, the target volume includes the involved vertebral body and both left and right pedicles and the grossly visible tumor, if a paraspinal or epidural lesion is present. The target volume is generally delineated with no margin. However, depending on the treatment system, a beam aperture margin of 2–3 mm beyond the target volume is allowed to ensure adequate dose coverage of the target. This margin can be reduced to 0–1 mm in the area of the spinal cord to meet spinal cord dose constraints. The target volume may be selected at the discretion of the treating radiation oncologist based on the extent of tumor involvement. In any circumstance in which there is an epidural or paraspinal soft tissue tumor component, the visible epidural or paraspinal tumors are included in the target volume [24].

Normal tissue contouring is required starting at 10 cm above the target volume to 10 cm below the target. The treatment plan should be established according to the recommended maximum dose limit for several critical organs, as shown in **Table 1**.

**133**

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

the immediate vicinity outside of the target volume [24].

radiation through the lungs [2].

**4. Comparison of plan result**

volume (PTV).

volume.

volume [53].

validation metric [51].

Among the dose-limiting critical OARs, the spinal cord is a key concern. Because of the nature of radiosurgery with a rapid dose falloff, there is a radiation dose gradient within the diameter of the spinal cord. Therefore, a partial spinal cord volume defined as from 5 to 6 mm above to 5–6 mm below the target volume is used. The partial or absolute volume spinal cord constraints are applied to each treated spine level when the patient has multiple spine levels treated. Any spinal cord dose

Successful treatment planning requires 90% coverage of the target volume by the prescribed dose. Typically, the 80–90% isodose line is used as the prescription line, although the prescription isodose line may be different depending on the delivery system. Coverage of <90% of the target volume is an acceptable variation, and any coverage of <80% of the target volume is an unacceptable deviation. The treatment plan is acceptable as long as ≥90% of the target volume receives the prescribed dose. It should be noted, however, that owing to the irregular shape of the target volume and the location of the spinal cord, hot spots may be created in

Because of the characteristics of the spinal SBRT, in the case of a beam with a small size, the higher the beam energy, the larger the beam penumbra as a result of lateral electron transport in the medium. The commonly available 5 mm MLC leaf width has been found to be adequate for most applications, with negligible improvements using the 3 mm leaf width MLC for all but the smallest lesions (<3 cm in diameter). A 6 MV photon beam, available on most modern treatment machines, provides a reasonable compromise between the beam penetration and penumbra characteristics. Additionally, beam arrays should be placed mostly in the posterior direction to avoid entrance of the radiation beam through the lungs. In the case of arc rotation techniques, every effort should be used to limit the passage of

In Section 3, several spinal SBRT planning techniques were discussed. Because the planning technique should be selected depending on the patient's condition or situation, numerous studies have been performed to compare various planning techniques for treating spinal tumors. To evaluate the results of each plan for spinal

• Conformity index (CI): a measure of the dose coverage to the planned target

• Dice similarity coefficient (DSC): a spatial overlap index and a reproducibility

• Homogeneity index (HI): a measure of uniformity of the dose within the target

• High-dose spillage: The cumulative volume of all tissue outside the PTV receiving a dose >105% of prescription dose should be no more than 15% of the PTV

• PTV coverage: 100% of the PTV receiving the prescribed dose [52].

• Spinal cord dose: maximum dose to the spinal cord.

SBRT, the following quantitative parameters were used [22, 47–50].

exceeding this constraint is not acceptable and is a major deviation [24].

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

### *Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques DOI: http://dx.doi.org/10.5772/intechopen.83515*

*Ionizing and Non-ionizing Radiation*

that of the Gammaknife (Elekta) and conventional LINACs, which have a fixed mechanical center of the gantry and collimator. The location of the isocenter is not limited, providing a great advantage over many other delivery units. However, this advantage can be overcome by using inverse planning; the final target dose distributions can be manipulated to a certain level by modifying the order of the targets as well as the contours and dose limits assigned to the target and critical organs.

*Dose-volume parameters in circular collimator and multi-leaf collimator (MLC) plans for 1–7 cm brain target volumes. (White bars indicate multi-leaf collimator (MLC) and gray indicate circular collimator.) Copyright* 

In non-isocentric treatment planning, radiation beams are delivered to a specific portion of the tumor without couch repositioning. This technique makes the highdose isodose lines match the target shape and avoid nearby critical organs. Therefore, non-isocentric planning is very useful for treatment of irregularly shaped targets. CK, which is available with both plans, is advantageous for combining the rapid dose falloff of isocentric plans with the dose conformity of non-isocentric plans [1].

In spinal SBRT, the target volume includes the involved vertebral body and both left and right pedicles and the grossly visible tumor, if a paraspinal or epidural lesion is present. The target volume is generally delineated with no margin. However, depending on the treatment system, a beam aperture margin of 2–3 mm beyond the target volume is allowed to ensure adequate dose coverage of the target. This margin can be reduced to 0–1 mm in the area of the spinal cord to meet spinal cord dose constraints. The target volume may be selected at the discretion of the treating radiation oncologist based on the extent of tumor involvement. In any circumstance in which there is an epidural or paraspinal soft tissue tumor component, the visible epidural or paraspinal tumors are included in the target volume [24]. Normal tissue contouring is required starting at 10 cm above the target volume to 10 cm below the target. The treatment plan should be established according to the recommended maximum dose limit for several critical organs, as shown in **Table 1**.

**132**

**3.5 Planning considerations**

**Figure 3.**

*© 2017, Oxford University Press.*

Among the dose-limiting critical OARs, the spinal cord is a key concern. Because of the nature of radiosurgery with a rapid dose falloff, there is a radiation dose gradient within the diameter of the spinal cord. Therefore, a partial spinal cord volume defined as from 5 to 6 mm above to 5–6 mm below the target volume is used. The partial or absolute volume spinal cord constraints are applied to each treated spine level when the patient has multiple spine levels treated. Any spinal cord dose exceeding this constraint is not acceptable and is a major deviation [24].

Successful treatment planning requires 90% coverage of the target volume by the prescribed dose. Typically, the 80–90% isodose line is used as the prescription line, although the prescription isodose line may be different depending on the delivery system. Coverage of <90% of the target volume is an acceptable variation, and any coverage of <80% of the target volume is an unacceptable deviation. The treatment plan is acceptable as long as ≥90% of the target volume receives the prescribed dose. It should be noted, however, that owing to the irregular shape of the target volume and the location of the spinal cord, hot spots may be created in the immediate vicinity outside of the target volume [24].

Because of the characteristics of the spinal SBRT, in the case of a beam with a small size, the higher the beam energy, the larger the beam penumbra as a result of lateral electron transport in the medium. The commonly available 5 mm MLC leaf width has been found to be adequate for most applications, with negligible improvements using the 3 mm leaf width MLC for all but the smallest lesions (<3 cm in diameter). A 6 MV photon beam, available on most modern treatment machines, provides a reasonable compromise between the beam penetration and penumbra characteristics. Additionally, beam arrays should be placed mostly in the posterior direction to avoid entrance of the radiation beam through the lungs. In the case of arc rotation techniques, every effort should be used to limit the passage of radiation through the lungs [2].

### **4. Comparison of plan result**

In Section 3, several spinal SBRT planning techniques were discussed. Because the planning technique should be selected depending on the patient's condition or situation, numerous studies have been performed to compare various planning techniques for treating spinal tumors. To evaluate the results of each plan for spinal SBRT, the following quantitative parameters were used [22, 47–50].


• Intermediate-dose spillage (R50% and D2cm): the falloff gradient located outside of the PTV.

R50%: volume that received 50% of the prescribed dose/PTV volume

D2cm: maximum dose in terms of the percentage of the prescribed dose at 2 cm beyond the PTV in any direction


In addition, plans were evaluated by the treatment delivery time (beam irradiated time) or the target point dose for the phantom measured in the ion chamber.

Zach et al. compared VMAT to static beam IMRT for spinal SBRT. The plans were compared for conformity, homogeneity, treatment delivery time, spinal cord dose, and Dmax of the spinal cord and V 10 Gy, which is the volume of the spinal cord exposed to at least 10 Gy. The authors also compared the monitor units required in each plan to compute the net irradiated time.

All evaluated parameters were shown to favor the VMAT plans over the IMRT plans. Dmin for PTV in the IMRT was significantly lower than that in the VMAT plan. The DSC and treatment time were found to be significantly better for the VMAT plans than for the IMRT plans. A reduction of almost 50% in the net treatment time was calculated. The authors reported that VMAT provides better conformity, homogeneity, and spinal cord dose. They also suggested that the shorter treatment time is a major advantage and not only provides convenience for patients experiencing pain but also contributes to the precision of this high-dose radiotherapy [47].

In another study, Choi et al. compared the treatment planning performance of RapidArc (i.e., VMAT) and CK for spinal SBRT. The optimized dose priorities for both plans were similar for all patients. The highest priority was to provide sufficient dose coverage to the PTV while limiting the maximum dose to the spinal cord. Plan quality was evaluated with respect to PTV coverage, CI, highdose spillage, intermediate-dose spillage, and maximum dose to the spinal cord, which are criteria recommended by the RTOG 0631 spine and 0915 lung SBRT protocols.

The mean CI ± standard deviation (SD) values of the PTV were 1.11 ± 0.03 and 1.17 ± 0.10 for RapidArc and CK, respectively. On average, the maximum dose delivered to the spinal cord in CK plans was approximately 11.6% higher than that in RapidArc plans. High-dose spillages were 0.86 and 2.26% for RapidArc and CK, respectively. Intermediate-dose spillage characterized by D2cm was lower for RapidArc than for CK; however, R50% was not statistically different between the plans. Although both systems can create highly conformal volumetric dose distributions, the study of Choi et al. shows that RapidArc was associated with lower high- and intermediate-dose spillages than was CK. The authors also suggested that RapidArc plans for spinal SBRT may be superior to CK plans [48].

**135**

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

Sahgal et al. compared the treatment planning quality of the CK and Novalis (BrainLAB AG, Heimstetten, Germany) systems for vertebral body SBRT. Physical parameters and biological modeling parameters such as PTV dose coverage, dose conformity, EUD, integral BED, and a generalized BED were used to compare the

In the study, both the CK and Novalis treatment plans fulfilled the specified requirements with comparable PTV dose coverage and dose conformity. For the target volume, CK plans produced significantly higher values of all calculated parameters to the PTV. For OARs, CK plans produced a somewhat lower dose to

The authors reported that restricting the dose to a small volume of the spinal

In another study, Kim et al. compared the planning characteristics for hypofractionated spinal SBRT administered using three treatment techniques (IMRT, mARC, and HT). The factors evaluated for spinal SBRT planning were dose cover-

Target dose coverage was 82.74 ± 3.35, 80.92 ± 0.81, and 85.01 ± 7.27% for IMRT, mARC, and HT, respectively. The authors reported that HT was therefore a powerful technique with respect to target coverage. The spinal cord dose for HT (mean, 1763.96 cGy; SD, 164.48) was significantly different from those for mARC (mean, 1991.75 cGy; SD, 248.00) and IMRT (mean, 2053.24 cGy; SD, 164.48). In addition, the partial spinal cord volume at 2000 cGy for HT (mean, 0.12 cc; SD, 0.01) was significantly different from those for IMRT and mARC (0.50 ± 0.10 cc and 0.56 ± 0.25 cc, respectively). The CIs were 1.30 ± 0.12, 1.08 ± 0.05, and 1.36 ± 0.23 for IMRT, mARC, and HT planning, respectively. mARC showed the highest conformity. Regarding HI, HT (mean, 1763.96 cGy; SD, 164.48) differed statistically from both mARC (mean, 1991.75 cGy; SD, 248.00) and IMRT (mean, 2053.24 cGy;

HT used a narrow field fan-beam and exhibited remarkable improvement of target coverage and cord dose, offering an important benefit to spinal SBRT. mARC had the highest target conformity and showed more favorable high- and intermediate-dose spillage than did HT and IMRT. These three planning techniques have different advantages. The authors suggested utilizing different planning techniques according to the cases. In the case of spinal SBRT, HT should be used for cord avoidance. In some cases, such as for a short treatment duration when the patient is

Gallo et al. performed end-to-end (E2E) testing for a set of representative spinal targets planned and delivered using four different treatment planning systems and delivery systems, specifically HT, Vero, TrueBeam with flattening filter free (FFF) and flattened, and CK, to evaluate the various capabilities of each. An anthropomorphic E2E SBRT phantom was simulated and treated on each system to evaluate agreement between measured and planned doses. The phantom accepted 0.007 cm3 ion chambers in the thoracic region and radiochromic film in the lumbar region. Ion chamber measurements in the thoracic targets resulted in an overall average difference of 1.5% with planned doses. Specifically, measurements agreed with the treatment planning system to within 2.2, 3.2, 1.4, 3.1, and 3.0% for all three measureable cases on HT, Vero, TrueBeam (FFF), TrueBeam (flattened), and CK, respectively. Film measurements for the lumbar targets resulted in average global gamma index passing rates of 100 at 3%/3 mm, 96.9 at 2%/2 mm, and 61.8 at 1%/1 mm, with a 10% minimum threshold for all plans on all platforms. Local

considered to be in poor general condition, mARC can be used [22].

these structures for CK planning but at the expense of a larger volume of these

volumes of these structures to a low dose as compared to the Novalis plans.

cord and esophagus resulted in a modest decrease in the dose to 1 cm3

age, cord avoidance, target conformity, homogeneity, and dose spillage.

) of the spinal cord and esophagus but exposed larger

volume of

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

structures exposed to low-dose levels [49].

SD, 164.48) with respect to the spinal cord dose.

treatment plans.

small volumes (0.1–1 cm3

*Ionizing and Non-ionizing Radiation*

outside of the PTV.

beyond the PTV in any direction

• Intermediate-dose spillage (R50% and D2cm): the falloff gradient located

R50%: volume that received 50% of the prescribed dose/PTV volume

• Equivalent uniform dose (EUD): the absorbed dose that, if homogeneously delivered to a tumor, causes the same expected number of clonogens to survive

• Biological effective dose (BED): the dose producing equivalent biological effect

• Gamma index: the standard method for planar dose verification in IMRT QA; calculates the quantity γ for each point of interest using preselected dose difference (DD) and distance to agreement (DTA) criteria and then uses the γ

In addition, plans were evaluated by the treatment delivery time (beam irradiated time) or the target point dose for the phantom measured in the ion chamber. Zach et al. compared VMAT to static beam IMRT for spinal SBRT. The plans were compared for conformity, homogeneity, treatment delivery time, spinal cord dose, and Dmax of the spinal cord and V 10 Gy, which is the volume of the spinal cord exposed to at least 10 Gy. The authors also compared the monitor units

All evaluated parameters were shown to favor the VMAT plans over the IMRT plans. Dmin for PTV in the IMRT was significantly lower than that in the VMAT plan. The DSC and treatment time were found to be significantly better for the VMAT plans than for the IMRT plans. A reduction of almost 50% in the net treatment time was calculated. The authors reported that VMAT provides better conformity, homogeneity, and spinal cord dose. They also suggested that the shorter treatment time is a major advantage and not only provides convenience for patients experiencing pain but also contributes to the precision of this high-dose radio-

In another study, Choi et al. compared the treatment planning performance of RapidArc (i.e., VMAT) and CK for spinal SBRT. The optimized dose priorities for both plans were similar for all patients. The highest priority was to provide sufficient dose coverage to the PTV while limiting the maximum dose to the spinal cord. Plan quality was evaluated with respect to PTV coverage, CI, highdose spillage, intermediate-dose spillage, and maximum dose to the spinal cord, which are criteria recommended by the RTOG 0631 spine and 0915 lung SBRT

The mean CI ± standard deviation (SD) values of the PTV were 1.11 ± 0.03 and

1.17 ± 0.10 for RapidArc and CK, respectively. On average, the maximum dose delivered to the spinal cord in CK plans was approximately 11.6% higher than that in RapidArc plans. High-dose spillages were 0.86 and 2.26% for RapidArc and CK, respectively. Intermediate-dose spillage characterized by D2cm was lower for RapidArc than for CK; however, R50% was not statistically different between the plans. Although both systems can create highly conformal volumetric dose distributions, the study of Choi et al. shows that RapidArc was associated with lower high- and intermediate-dose spillages than was CK. The authors also suggested that

RapidArc plans for spinal SBRT may be superior to CK plans [48].

as does the actual nonhomogeneous absorbed dose distribution.

value to determine the outcome (pass-fail) of the IMRT QA [53].

regardless of dose uniformity or fractionations.

required in each plan to compute the net irradiated time.

D2cm: maximum dose in terms of the percentage of the prescribed dose at 2 cm

**134**

therapy [47].

protocols.

Sahgal et al. compared the treatment planning quality of the CK and Novalis (BrainLAB AG, Heimstetten, Germany) systems for vertebral body SBRT. Physical parameters and biological modeling parameters such as PTV dose coverage, dose conformity, EUD, integral BED, and a generalized BED were used to compare the treatment plans.

In the study, both the CK and Novalis treatment plans fulfilled the specified requirements with comparable PTV dose coverage and dose conformity. For the target volume, CK plans produced significantly higher values of all calculated parameters to the PTV. For OARs, CK plans produced a somewhat lower dose to small volumes (0.1–1 cm3 ) of the spinal cord and esophagus but exposed larger volumes of these structures to a low dose as compared to the Novalis plans.

The authors reported that restricting the dose to a small volume of the spinal cord and esophagus resulted in a modest decrease in the dose to 1 cm3 volume of these structures for CK planning but at the expense of a larger volume of these structures exposed to low-dose levels [49].

In another study, Kim et al. compared the planning characteristics for hypofractionated spinal SBRT administered using three treatment techniques (IMRT, mARC, and HT). The factors evaluated for spinal SBRT planning were dose coverage, cord avoidance, target conformity, homogeneity, and dose spillage.

Target dose coverage was 82.74 ± 3.35, 80.92 ± 0.81, and 85.01 ± 7.27% for IMRT, mARC, and HT, respectively. The authors reported that HT was therefore a powerful technique with respect to target coverage. The spinal cord dose for HT (mean, 1763.96 cGy; SD, 164.48) was significantly different from those for mARC (mean, 1991.75 cGy; SD, 248.00) and IMRT (mean, 2053.24 cGy; SD, 164.48). In addition, the partial spinal cord volume at 2000 cGy for HT (mean, 0.12 cc; SD, 0.01) was significantly different from those for IMRT and mARC (0.50 ± 0.10 cc and 0.56 ± 0.25 cc, respectively). The CIs were 1.30 ± 0.12, 1.08 ± 0.05, and 1.36 ± 0.23 for IMRT, mARC, and HT planning, respectively. mARC showed the highest conformity. Regarding HI, HT (mean, 1763.96 cGy; SD, 164.48) differed statistically from both mARC (mean, 1991.75 cGy; SD, 248.00) and IMRT (mean, 2053.24 cGy; SD, 164.48) with respect to the spinal cord dose.

HT used a narrow field fan-beam and exhibited remarkable improvement of target coverage and cord dose, offering an important benefit to spinal SBRT. mARC had the highest target conformity and showed more favorable high- and intermediate-dose spillage than did HT and IMRT. These three planning techniques have different advantages. The authors suggested utilizing different planning techniques according to the cases. In the case of spinal SBRT, HT should be used for cord avoidance. In some cases, such as for a short treatment duration when the patient is considered to be in poor general condition, mARC can be used [22].

Gallo et al. performed end-to-end (E2E) testing for a set of representative spinal targets planned and delivered using four different treatment planning systems and delivery systems, specifically HT, Vero, TrueBeam with flattening filter free (FFF) and flattened, and CK, to evaluate the various capabilities of each. An anthropomorphic E2E SBRT phantom was simulated and treated on each system to evaluate agreement between measured and planned doses. The phantom accepted 0.007 cm3 ion chambers in the thoracic region and radiochromic film in the lumbar region.

Ion chamber measurements in the thoracic targets resulted in an overall average difference of 1.5% with planned doses. Specifically, measurements agreed with the treatment planning system to within 2.2, 3.2, 1.4, 3.1, and 3.0% for all three measureable cases on HT, Vero, TrueBeam (FFF), TrueBeam (flattened), and CK, respectively. Film measurements for the lumbar targets resulted in average global gamma index passing rates of 100 at 3%/3 mm, 96.9 at 2%/2 mm, and 61.8 at 1%/1 mm, with a 10% minimum threshold for all plans on all platforms. Local

gamma analysis was also performed with similar results. While gamma passing rates were consistently accurate across all platforms through 2%/2 mm, treatment beam-on delivery times varied greatly among the platforms, with TrueBeam (FFF) the shortest, averaging 4.4 min, TrueBeam using flattened beam at 9.5 min, HT at 30.5 min, Vero at 19 min, and CK at 46.0 min.

In the study, despite the complexity of the representative targets and their proximity to the spinal cord, all treatment platforms were able to create plans that meet all RTOG 0631 dose constraints and produced exceptional agreement between calculated and measured doses. However, there were differences in the plan characteristics and significant differences in the beam-on delivery time between platforms. Thus, the authors stated that clinical judgment is required in each particular case to determine the most appropriate treatment planning/delivery platform [50].

### **5. Conclusion**

This chapter has described various planning techniques for spinal SBRT and summarized the studies comparing these techniques. The spine is a frequent site of tumor metastasis, but there are many important vessels and adjacent organs in the vicinity of the vertebrae. In particular, the spinal cord within the spine is part of the central nervous system. Radiotherapy is performed depending on the malignancy of the tumor or the difficulty of complete resection, considering potential spinal instability caused by the tumor destruction or complete resection. However, the major limitation of traditional radiotherapy is the tolerance dose of the spinal cord. If the spinal cord is irradiated with an overdose, toxicities such as radiation-induced myelopathy, vertebral compression fracture, or pain flare may occur. To overcome the limitation of conventional radiotherapy, SBRT has been proposed. The technique of SBRT delivers a higher BED, within the range of what is considered locally curative. A conformal high-dose beam in a few fractions should be used, and an intensity modulation technique is required for the sparing of normal organs surrounding the spinal lesion. Various planning technologies based on intensity modulation technology are available, including IMRT with fixed gantry, IMAT, HT, and CK. Different planning techniques have their distinct features and advantages. Therefore, it is important to use appropriate treatment planning depending on the patient's condition and situation.

### **Acknowledgements**

This research was supported by Advanced Institute for Radiation Fusion Medical Technology (AIRFMT) at the Catholic University of Korea.

**137**

**Author details**

, Yunji Seol1

, Hong Seok Jang2

1 The Catholic University of Korea, Seoul, Republic of Korea

\*Address all correspondence to: ynkang33@gmail.com

Jina Kim1

provided the original work is properly cited.

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques*

*DOI: http://dx.doi.org/10.5772/intechopen.83515*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

and Young-Nam Kang2

\*

### **Conflict of interest**

The authors report no conflicts of interest.

*Spinal Stereotactic Body Radiotherapy (SBRT) Planning Techniques DOI: http://dx.doi.org/10.5772/intechopen.83515*

*Ionizing and Non-ionizing Radiation*

**5. Conclusion**

patient's condition and situation.

**Acknowledgements**

**Conflict of interest**

30.5 min, Vero at 19 min, and CK at 46.0 min.

gamma analysis was also performed with similar results. While gamma passing rates were consistently accurate across all platforms through 2%/2 mm, treatment beam-on delivery times varied greatly among the platforms, with TrueBeam (FFF) the shortest, averaging 4.4 min, TrueBeam using flattened beam at 9.5 min, HT at

In the study, despite the complexity of the representative targets and their proximity to the spinal cord, all treatment platforms were able to create plans that meet all RTOG 0631 dose constraints and produced exceptional agreement between calculated and measured doses. However, there were differences in the plan characteristics and significant differences in the beam-on delivery time between platforms. Thus, the authors stated that clinical judgment is required in each particular case to determine the most appropriate treatment planning/delivery platform [50].

This chapter has described various planning techniques for spinal SBRT and summarized the studies comparing these techniques. The spine is a frequent site of tumor metastasis, but there are many important vessels and adjacent organs in the vicinity of the vertebrae. In particular, the spinal cord within the spine is part of the central nervous system. Radiotherapy is performed depending on the malignancy of the tumor or the difficulty of complete resection, considering potential spinal instability caused by the tumor destruction or complete resection. However, the major limitation of traditional radiotherapy is the tolerance dose of the spinal cord. If the spinal cord is irradiated with an overdose, toxicities such as radiation-induced myelopathy, vertebral compression fracture, or pain flare may occur. To overcome the limitation of conventional radiotherapy, SBRT has been proposed. The technique of SBRT delivers a higher BED, within the range of what is considered locally curative. A conformal high-dose beam in a few fractions should be used, and an intensity modulation technique is required for the sparing of normal organs surrounding the spinal lesion. Various planning technologies based on intensity modulation technology are available, including IMRT with fixed gantry, IMAT, HT, and CK. Different planning techniques have their distinct features and advantages. Therefore, it is important to use appropriate treatment planning depending on the

This research was supported by Advanced Institute for Radiation Fusion Medical

Technology (AIRFMT) at the Catholic University of Korea.

The authors report no conflicts of interest.

**136**

### **Author details**

Jina Kim1 , Yunji Seol1 , Hong Seok Jang2 and Young-Nam Kang2 \*

1 The Catholic University of Korea, Seoul, Republic of Korea

2 Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

\*Address all correspondence to: ynkang33@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[53] Bezjak A, Papiez L, Bradley J, Gore E, Gaspar L, Kong MF-MSP, et al. RTOG 0813 Seamless Phase I/II Study Of Stereotactic Lung Radiotherapy (SBRT) for Early Stage, Centrally Located, Non-Small Cell Lung Cancer (NSCLC) In Medically Inoperable Patients. 2009. Available from: https://www.rtog.org/ClinicalTrials/

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[47] Zach L, Tsvang L, Alezra D, Ben Ayun M, Harel R. Volumetric modulated arc therapy for spine radiosurgery: Superior treatment planning and delivery compared to static beam intensity modulated radiotherapy. BioMed Research International. 2016;**2016**:6

[48] Choi YE, Kwak J, Song SY, Choi EK, Do Ahn S, Cho B. Direct plan comparison of RapidArc and CyberKnife for spine stereotactic body radiation therapy. Journal of the Korean Physical Society. 2015;**67**(1):116-122

[49] Sahgal A, Chuang C, Hossain S, Petti P, Larson DA, Shrieve DC, et al. Comparisons of Novalis and CyberKnife® spinal stereotactic body radiotherapy treatment planning based on physical and biological modeling parameters. In: Radiosurgery. Switzerland: Karger Publishers; 2010;**7**:366-377

[50] Gallo JJ, Kaufman I, Powell R, Pandya S, Somnay A, Bossenberger T, et al. Single-fraction spine SBRT end-to-end testing on TomoTherapy, Vero, TrueBeam, and CyberKnife treatment platforms using a novel anthropomorphic phantom. Journal of Applied Clinical Medical Physics. 2015;**16**(1):170-182

[51] Zou KH, Warfield SK, Bharatha A, Tempany CM, Kaus MR, Haker SJ, et al. Statistical validation of image segmentation quality based on a spatial overlap index1: Scientific reports. Academic Radiology. 2004;**11**(2):178-189

[52] Krishnan J, Shetty J, Rao S, Hegde S, Shambhavi C. Comparison of rapid arc and intensity-modulated radiotherapy plans using unified dosimetry index and the impact of conformity index on unified dosimetry index evaluation. Journal of Medical Physics. 2017;**42**(1):14

[53] Bezjak A, Papiez L, Bradley J, Gore E, Gaspar L, Kong MF-MSP, et al. RTOG 0813 Seamless Phase I/II Study Of Stereotactic Lung Radiotherapy (SBRT) for Early Stage, Centrally Located, Non-Small Cell Lung Cancer (NSCLC) In Medically Inoperable Patients. 2009. Available from: https://www.rtog.org/ClinicalTrials/ ProtocolTable/StudyDetails. aspx?study=0813

Section 3

Radioactivity

143

Section 3 Radioactivity

Chapter 8

Markus Zehringer

Abstract

1. Introduction

nuclides.

145

Monitoring of Natural

are monitored for their content of natural radionuclides.

Radioactivity in Drinking Water

Alpha spectrometry is an indispensable technique in the radiology lab for the analysis of natural radionuclides. While the powerful ICP/MS is used more and more for the analysis of uranium and thorium, other radionuclides, such as 226Ra, are difficult to analyze with this technique due to their very high specific activities. The following chapter is introduced by a description of the problems, which may occur when working in the ultra-trace level. A description of the commonly used extraction and enrichment techniques for alpha nuclides and a short survey of the commonly applied detection techniques are given. The main application of alpha spectrometry in our laboratory is the monitoring of tap and mineral waters. Besides water, some specific food categories, such as fish, seafood, spices or healing earths,

Keywords: alpha spectrometry, mineral water, seafood, spices, healing earth

in minerals, such as pitch blend (uranium) or monazites (thorium).

Uranium and thorium are radionuclides with long half-lives. Their abundances in the earth's crust are 12–13 ppm rsp. 2.5 ppm for thorium and uranium. They exist

From the earth's crust, these elements migrate to the groundwater layers. There, they can be transferred to surface waters. Therefore, the consummation of water is a main direct source for the ingestion of alpha nuclides. In addition, they are taken up by aquatic organisms (fish, mussels) and enriched in these organisms (e.g. Po-210 (210Po) is enriched in the intestinal tract of mussels and fish). Alpha nuclides are enriched in farmland soils by irrigation and the application of phosphate fertilizers, which contain respectable amounts of uranium and thorium. The consummation of vegetables cultivated on such farmlands and the consummation of meat and meat products from these farms is another possibility for the intake of alpha

There exist three main decay series of natural radionuclides starting from the radionuclides uranium-238 (238U), thorium-232 (232Th) and uranium-235 (235U). The 238U decay chain produces several radionuclides, which are of radiological concern. These are 238U, 234U, radium-226 (226Ra), radon-222 (222Rn), lead-210

and Food with Emphasis on

Alpha-Emitting Radionuclides

### Chapter 8

## Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis on Alpha-Emitting Radionuclides

Markus Zehringer

### Abstract

Alpha spectrometry is an indispensable technique in the radiology lab for the analysis of natural radionuclides. While the powerful ICP/MS is used more and more for the analysis of uranium and thorium, other radionuclides, such as 226Ra, are difficult to analyze with this technique due to their very high specific activities. The following chapter is introduced by a description of the problems, which may occur when working in the ultra-trace level. A description of the commonly used extraction and enrichment techniques for alpha nuclides and a short survey of the commonly applied detection techniques are given. The main application of alpha spectrometry in our laboratory is the monitoring of tap and mineral waters. Besides water, some specific food categories, such as fish, seafood, spices or healing earths, are monitored for their content of natural radionuclides.

Keywords: alpha spectrometry, mineral water, seafood, spices, healing earth

### 1. Introduction

Uranium and thorium are radionuclides with long half-lives. Their abundances in the earth's crust are 12–13 ppm rsp. 2.5 ppm for thorium and uranium. They exist in minerals, such as pitch blend (uranium) or monazites (thorium).

From the earth's crust, these elements migrate to the groundwater layers. There, they can be transferred to surface waters. Therefore, the consummation of water is a main direct source for the ingestion of alpha nuclides. In addition, they are taken up by aquatic organisms (fish, mussels) and enriched in these organisms (e.g. Po-210 (210Po) is enriched in the intestinal tract of mussels and fish). Alpha nuclides are enriched in farmland soils by irrigation and the application of phosphate fertilizers, which contain respectable amounts of uranium and thorium. The consummation of vegetables cultivated on such farmlands and the consummation of meat and meat products from these farms is another possibility for the intake of alpha nuclides.

There exist three main decay series of natural radionuclides starting from the radionuclides uranium-238 (238U), thorium-232 (232Th) and uranium-235 (235U). The 238U decay chain produces several radionuclides, which are of radiological concern. These are 238U, 234U, radium-226 (226Ra), radon-222 (222Rn), lead-210

food at so-called emergency situations are included. For "planed exposition situations" (this means normal situations without any fallout event), no limit values at all are defined. Fortunately, limit values for radiocesium, an important beta-emitter in fallout, are regulated in the Ordinance on the Importation and the Placing on the Market of Food, which is contaminated following the Accident of the Nuclear Power Station of Chernobyl (Chernobyl Ordinance) [5] and the Ordinance on Food originating in or consigned from Japan (Fukushima Ordinance) [6]. Unfortunately, the limit

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

In Switzerland, a better legal basis exists only for drinking water. The Ordinance

Euratom

Bq/L 0.1 0.1

Bq/L 0.1 0.7 1

WHO guidance level

on Drinking Water and Water from Public Baths and Shower Facilities (TBDV) includes a limit value for uranium and guide values for tritium and radon and the parameter indicative dose [7]. This ordinance is based on the European Council Directive 2013/51/Euratom [8]. Fortunately, this council directive prescribes some

Lead-210 (210Pb) Bq/L 0.2 0.1

Radium-226 (226Ra) Bq/L 0.5 1 Radium-228 (228Ra) Bq/L 0.2 0.1 Radon (222Rn) Bq/L 100 100 — Thorium-228 (228Th) Bq/L 1 Thorium-230 (230Th) Bq/L 1 Thorium-232 (232Th) Bq/L 1 Uranium-238 (238U) Bq/L 3.0 10 Uranium-234 (234U) Bq/L 2.8 1

Carbon-14 (14C) Bq/L 240 100 Cesium-134 (134Cs) Bq/L 7.2 10 Cesium-137 (137Cs) Bq/L 11 10 Cobalt-60 (60Co) Bq/L 40 100 Iodine-131 (131I) Bq/L 6.2 6.2 10 Plutonium 239 + 240Pu Bq/L 0.6 1 Strontium-90 (90Sr) Bq/L 4.9 4.9 10

H) Bq/L 100 100 10,000

TBDV, Swiss ordinance on drinking water and water for public baths and shower facilities [7]; Euratom, council

Guidance levels for drinking water in EU and Switzerland compared to the WHO guidance levels.

Radionuclide TBDV Derived activity limits according to

values for radiocesium are different in each ordinance.

DOI: http://dx.doi.org/10.5772/intechopen.90166

Uranium\* μg/L 30 —

Indicative dose (ID) mSv 0.1 0.1

natural radionuclides

Polonium-210

Artificial radionuclides Americium-241

Tritium (3

\*

147

Table 1.

directive 2013/51/Euratom [8]; WHO [9].

uranium is calculated from the activity of 238U.

( 241Am)

( 210Po)

### Figure 1.

Natural decay series of uranium and thorium. Alpha decays are symbolized with a horizontal arrow. The small diagonal arrows indicate a beta decay. In the nuclide box, the half-life is given. All data from [1].

( 210Pb) and 210Po. The chain ends at the stable lead isotope 206Pb. The 232Th-decay chain comprises 232Th, radium-228 (228Ra), thorium-228 (228Th), radium-224 ( 224Ra) and radon-220 (220Rn), which are of radiological relevance. The chain stops at the stable lead isotope 208Pb. The Uranium-235 decay chain produces the following relevant radionuclides: 235U, protactinium-231 (231Pa), actinium-227 (227Ac), thorium-227 (227Th) and radium-223 (223Ra). The chain stops at the stable lead isotope lead-207 (207Pb). Figure 1 shows the decay paths of the three decay series.

Radionuclides with longer half-lives, more than days, are of interest. Nevertheless, all radionuclides in the three decay chains are of radiological concern. The short-lived radionuclides cannot be considered separately. Therefore, the long-lived radionuclides and their short-lived daughter nuclides are assessed together. The conversion factor of a specific radionuclide considers the radiation of the following short-lived daughter nuclides.

Radon nuclides are radionuclides of the decay chains, which are gaseous. Therefore, they can be translocated by outgassing from the soil. That means, the radon nuclide and its follower nuclides are transported away from the soil or other environmental matrices that contain radium isotopes. Consequently, radon nuclides can be dislocated from its point of origin. 222Rn can leave the soil due to its relatively long half-life of 3.8 days. One estimates that about 50% of the radon can leave the soil from a depth of 1 m [2]. In the air, the decay of the radon produces after several decay steps the longer-lived 210Pb, 210Bi and 210Po, which are transported on dust particles through the atmosphere and may reach again farmland and surface waters. For the two other decay chains, this effect can be neglected. 219Rn and 220Rn are disintegrated before they have left the soil. In addition, the decay of these two radon species produces only short-lived radionuclides.

### 2. EU and Swiss legislation for radionuclides

Since 2018, in Swiss legislation most limit values for radionuclides for food were deleted after the adaption of the ordinances to the legislation of the European Union. The Federal Ordinance on Contaminants and Constituents in Food from 1994 was expired [3], and a new Ordinance on Maximum Limits for Contaminants was put into force in May 1, 2017 [4]. In this new ordinance, limit values for radionuclides in Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

food at so-called emergency situations are included. For "planed exposition situations" (this means normal situations without any fallout event), no limit values at all are defined. Fortunately, limit values for radiocesium, an important beta-emitter in fallout, are regulated in the Ordinance on the Importation and the Placing on the Market of Food, which is contaminated following the Accident of the Nuclear Power Station of Chernobyl (Chernobyl Ordinance) [5] and the Ordinance on Food originating in or consigned from Japan (Fukushima Ordinance) [6]. Unfortunately, the limit values for radiocesium are different in each ordinance.

In Switzerland, a better legal basis exists only for drinking water. The Ordinance on Drinking Water and Water from Public Baths and Shower Facilities (TBDV) includes a limit value for uranium and guide values for tritium and radon and the parameter indicative dose [7]. This ordinance is based on the European Council Directive 2013/51/Euratom [8]. Fortunately, this council directive prescribes some


TBDV, Swiss ordinance on drinking water and water for public baths and shower facilities [7]; Euratom, council directive 2013/51/Euratom [8]; WHO [9]. \*

### uranium is calculated from the activity of 238U.

### Table 1.

Guidance levels for drinking water in EU and Switzerland compared to the WHO guidance levels.

(

Figure 1.

(

146

short-lived daughter nuclides.

Ionizing and Non-ionizing Radiation

species produces only short-lived radionuclides.

2. EU and Swiss legislation for radionuclides

210Pb) and 210Po. The chain ends at the stable lead isotope 206Pb. The 232Th-decay chain comprises 232Th, radium-228 (228Ra), thorium-228 (228Th), radium-224

Natural decay series of uranium and thorium. Alpha decays are symbolized with a horizontal arrow. The small

diagonal arrows indicate a beta decay. In the nuclide box, the half-life is given. All data from [1].

224Ra) and radon-220 (220Rn), which are of radiological relevance. The chain stops at the stable lead isotope 208Pb. The Uranium-235 decay chain produces the following relevant radionuclides: 235U, protactinium-231 (231Pa), actinium-227 (227Ac), thorium-227 (227Th) and radium-223 (223Ra). The chain stops at the stable lead isotope lead-207 (207Pb). Figure 1 shows the decay paths of the three decay series. Radionuclides with longer half-lives, more than days, are of interest. Nevertheless, all radionuclides in the three decay chains are of radiological concern. The short-lived radionuclides cannot be considered separately. Therefore, the long-lived radionuclides and their short-lived daughter nuclides are assessed together. The conversion factor of a specific radionuclide considers the radiation of the following

Radon nuclides are radionuclides of the decay chains, which are gaseous. Therefore, they can be translocated by outgassing from the soil. That means, the radon nuclide and its follower nuclides are transported away from the soil or other environmental matrices that contain radium isotopes. Consequently, radon nuclides can be dislocated from its point of origin. 222Rn can leave the soil due to its relatively long half-life of 3.8 days. One estimates that about 50% of the radon can leave the soil from a depth of 1 m [2]. In the air, the decay of the radon produces after several decay steps the longer-lived 210Pb, 210Bi and 210Po, which are transported on dust particles through the atmosphere and may reach again farmland and surface waters. For the two other decay chains, this effect can be neglected. 219Rn and 220Rn are disintegrated before they have left the soil. In addition, the decay of these two radon

Since 2018, in Swiss legislation most limit values for radionuclides for food were

deleted after the adaption of the ordinances to the legislation of the European Union. The Federal Ordinance on Contaminants and Constituents in Food from 1994 was expired [3], and a new Ordinance on Maximum Limits for Contaminants was put into force in May 1, 2017 [4]. In this new ordinance, limit values for radionuclides in more guidance limits, "derived activity limits", for artificial and natural radionuclides. Therefore, these activity limits are also applicable in Switzerland. Table 1 summarizes the actual valid guidance and limit values for drinking water existing in Europe and Switzerland.

Another important point is the choice of adequate sample containers. For metal trace analysis, no glass containers should be used. The active surface of glass bottles acts like an ion exchanger. SiOH groups are potent ligands for metal ions and may adsorb ions from the water sample. One possibility to omit these adsorptive effects is the conservation of the sample with mineral acid, such as nitric acid, hydrochloric acid or sulphuric acid. SiOH groups are then protonated, and the adsorption of cations is hindered. One can also add carrier ions to obtain the same effect. This is a commonly used technique in radiochemical analyses. Addition of stable isotopes of the analytes in higher concentrations prevents such adsorptive effects. Another possibility is to precipitate radio traces by adding carriers (co-precipitation). Another possibility is to catch and stabilize the analyte with a chelating agent, such as EDTA, to prevent absorptive losses. Samples may also be dried at 105°C for

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

To overcome the possibility of such losses of analytes, we recommend using plastic bottles of polyethylene, PVC or Teflon, whenever possible. Pyrex (borosilicate glass) or soda glass containers should be avoided [13, 15, 16]. The containers should be soaked in diluted acid and rinsed thoroughly with distilled water before use. Before the sampling, the bottles are rinsed several times with the sample water [12]. It is also advisable to stabilize samples with the addition of conc. Nitric or hydrochloric acid, if the applied procedure does allow this (pH should be below 1). A stabilization is necessary when samples cannot be analyzed immediately (losses or transformation by bacteria, co-precipitation with suspended matter, etc. must be

A special case is the sampling of the gaseous radon. Here, losses may occur when samples are collected under turbulences or bottles are not completely filled, leaving some headspace. Radon will outgas partially. Here, it is advisable to collect the water without turbulences in glass bottles under water, if possible. The bottles must be filled to the top without letting back any air bubbles. For sampling of water from taps or valves, a simple method is to let stream the water through a plastic tube connected to a funnel and to fill the bottle from the bottom up to the top without turbulences. Then, the bottle is closed with a glass stopper displacing the water in the bottleneck. Normally, the radon activities in water are in the Bq/L range, so loss effects by adsorption effects on glass walls may not be noticed. The bottles should be transported to the lab at low temperature, but a freezing of the sample should be avoided. The samples must

One should take special care to choose acids and other chemicals of high quality. They should be of sufficiently high purity. Concentrated mineral acid solutions (e.g. 65% nitric acid, 95% sulphuric acid) and other chemicals should be of the same quality used for ICP, AAS or XRF analysis. These are, for example, mineral acids of suprapur quality from Sigma-Aldrich, Merck, Roth, etc. For these products, specification data sheets with the declaration of minimum trace amounts of most metals are available. For every method, a careful check of the whole blank (chemicals used, demineralized water, glassware for sample preparation, etc.) is important and is a matter of course.

Alpha rays have a short reach due to its high mass and dual positive mass (two protons and two neutrons). Therefore, the matrix absorbs most alpha radiation. Alpha rays can leave the sample only from very thin surfaces. To detect alpha rays,

be analyzed within a week due to the fast disintegration of the radon [11].

3.3 Quality of standards and chemicals

4. Sample preparation techniques

149

conservation or by freeze-drying, for example, of milk.

DOI: http://dx.doi.org/10.5772/intechopen.90166

avoided) [11, 12, 16].

### 3. Collection and conservation of water samples

In this short chapter, important tips for a good analytical practice are given. Sample collection and storage can be the source of basic errors, which can no more be eliminated, even using a sophisticated analytical technique. At first, we must remember the concentration level we are working at.

### 3.1 Specific activity

When analyzing radio traces, one must keep in mind the very low chemical concentrations one is dealing with. Due to short half-lives (between hours and days), the specific activity of many species is very high. This means that very low, mostly non-weighable chemical concentrations correspond to measurable activities in the mBq range. Practical work with such traces requires the addition of inactive carriers. The following table illustrates this effect [10]. 232Th and 238U are exceptions. Both nuclides decay with half-lives of billion years. Therefore, common activities correspond to weighable chemical amounts (Table 2).

These very low concentrations must be kept in mind, when samples are collected and prepared for radio trace analyses. The problems, which can occur, are losses of the analytes or contaminations during collection, transport, conservation and preparation of samples.

### 3.2 Sample collection and storage

From natural waters, it is a major problem to obtain representative samples, e.g. out of a river. Trace element concentrations depend on depth, salinity and turbidity of a river or lake. Groundwater samples collected by using a pump should be taken some minutes after beginning of the pumping to avoid the collection of the standing water in the pipe. At this point, we cannot explicate profoundly the challenges for adequate sampling. We recommend consulting the relevant literature, e.g. [11–13].


Activity limits according to ordinance on drinking water and water for public baths and shower facilities (TBDV) [7].

### Table 2.

Specific activities of some dose-relevant natural radionuclides.

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

Another important point is the choice of adequate sample containers. For metal trace analysis, no glass containers should be used. The active surface of glass bottles acts like an ion exchanger. SiOH groups are potent ligands for metal ions and may adsorb ions from the water sample. One possibility to omit these adsorptive effects is the conservation of the sample with mineral acid, such as nitric acid, hydrochloric acid or sulphuric acid. SiOH groups are then protonated, and the adsorption of cations is hindered. One can also add carrier ions to obtain the same effect. This is a commonly used technique in radiochemical analyses. Addition of stable isotopes of the analytes in higher concentrations prevents such adsorptive effects. Another possibility is to precipitate radio traces by adding carriers (co-precipitation). Another possibility is to catch and stabilize the analyte with a chelating agent, such as EDTA, to prevent absorptive losses. Samples may also be dried at 105°C for conservation or by freeze-drying, for example, of milk.

To overcome the possibility of such losses of analytes, we recommend using plastic bottles of polyethylene, PVC or Teflon, whenever possible. Pyrex (borosilicate glass) or soda glass containers should be avoided [13, 15, 16]. The containers should be soaked in diluted acid and rinsed thoroughly with distilled water before use. Before the sampling, the bottles are rinsed several times with the sample water [12].

It is also advisable to stabilize samples with the addition of conc. Nitric or hydrochloric acid, if the applied procedure does allow this (pH should be below 1). A stabilization is necessary when samples cannot be analyzed immediately (losses or transformation by bacteria, co-precipitation with suspended matter, etc. must be avoided) [11, 12, 16].

A special case is the sampling of the gaseous radon. Here, losses may occur when samples are collected under turbulences or bottles are not completely filled, leaving some headspace. Radon will outgas partially. Here, it is advisable to collect the water without turbulences in glass bottles under water, if possible. The bottles must be filled to the top without letting back any air bubbles. For sampling of water from taps or valves, a simple method is to let stream the water through a plastic tube connected to a funnel and to fill the bottle from the bottom up to the top without turbulences. Then, the bottle is closed with a glass stopper displacing the water in the bottleneck. Normally, the radon activities in water are in the Bq/L range, so loss effects by adsorption effects on glass walls may not be noticed. The bottles should be transported to the lab at low temperature, but a freezing of the sample should be avoided. The samples must be analyzed within a week due to the fast disintegration of the radon [11].

### 3.3 Quality of standards and chemicals

One should take special care to choose acids and other chemicals of high quality. They should be of sufficiently high purity. Concentrated mineral acid solutions (e.g. 65% nitric acid, 95% sulphuric acid) and other chemicals should be of the same quality used for ICP, AAS or XRF analysis. These are, for example, mineral acids of suprapur quality from Sigma-Aldrich, Merck, Roth, etc. For these products, specification data sheets with the declaration of minimum trace amounts of most metals are available. For every method, a careful check of the whole blank (chemicals used, demineralized water, glassware for sample preparation, etc.) is important and is a matter of course.

### 4. Sample preparation techniques

Alpha rays have a short reach due to its high mass and dual positive mass (two protons and two neutrons). Therefore, the matrix absorbs most alpha radiation. Alpha rays can leave the sample only from very thin surfaces. To detect alpha rays,

more guidance limits, "derived activity limits", for artificial and natural radionuclides. Therefore, these activity limits are also applicable in Switzerland. Table 1 summarizes the actual valid guidance and limit values for drinking water existing in

In this short chapter, important tips for a good analytical practice are given. Sample collection and storage can be the source of basic errors, which can no more be eliminated, even using a sophisticated analytical technique. At first, we must

When analyzing radio traces, one must keep in mind the very low chemical concentrations one is dealing with. Due to short half-lives (between hours and days), the specific activity of many species is very high. This means that very low, mostly non-weighable chemical concentrations correspond to measurable activities in the mBq range. Practical work with such traces requires the addition of inactive carriers. The following table illustrates this effect [10]. 232Th and 238U are exceptions. Both nuclides decay with half-lives of billion years. Therefore, common

These very low concentrations must be kept in mind, when samples are collected and prepared for radio trace analyses. The problems, which can occur, are losses of the analytes or contaminations during collection, transport, conservation and prep-

From natural waters, it is a major problem to obtain representative samples, e.g. out of a river. Trace element concentrations depend on depth, salinity and turbidity of a river or lake. Groundwater samples collected by using a pump should be taken some minutes after beginning of the pumping to avoid the collection of the standing water in the pipe. At this point, we cannot explicate profoundly the challenges for adequate sampling. We recommend consulting the relevant literature, e.g. [11–13].

> Activity limits in tap water (Bq/L)\*

Corresponding concentration μg/L (ppb)

3. Collection and conservation of water samples

remember the concentration level we are working at.

activities correspond to weighable chemical amounts (Table 2).

MBq/kg

222Rn 3.8 d 5.7 10<sup>12</sup> 100 2 10<sup>11</sup> 210Po 138 d 1.66 10<sup>11</sup> 0.10 6 10<sup>10</sup> 210Pb 22.3 a 2.8 10<sup>9</sup> 0.20 4 10<sup>8</sup> 228Ra 5.75 a 1.0 1010 0.20 1 10<sup>7</sup> 226Ra 1600 a 3.4 10<sup>7</sup> 0.50 3 10<sup>6</sup> 238U 4.4 10<sup>9</sup> a 12.5 3 8.1 232Th 1.4 1010 a 4.06 1 24

Activity limits according to ordinance on drinking water and water for public baths and shower facilities (TBDV) [7].

Europe and Switzerland.

Ionizing and Non-ionizing Radiation

3.1 Specific activity

aration of samples.

\*

148

Table 2.

3.2 Sample collection and storage

Radionuclide Half-life Specific activity

Specific activities of some dose-relevant natural radionuclides.

one must eliminate the matrix without losing the alpha nuclides. The following survey is not a complete review of the commonly used techniques. It is more focused on the applied procedures at the state laboratory of Basel City. This focus allows us to report from our long-time experience in alpha spectrometry.

Many other extraction systems were published. For example, Leeuwen et al. published an overview on the selective extraction of radium with means of chelators

The use of some specific active surfaces, which are suitable for the adsorption of

Such selective phases can be made of pure metals, such as copper, nickel or silver. 210Po will auto adsorb on such a surface in an acidic, reductive milieu using ascorbic acid or hydroxylamine [38–41]. For recovery control of the adsorption process, polonium-208 (208Po) or polonium-209 (209Po) can be added as tracers. Manganese dioxide-coated surfaces adsorb radium nuclides selectively. Based on the work of Moore and Reid [42], Glöbel and Berlich [43] and Surbeck [44], robust procedures for the analysis of radium in water were developed by Eikenberg et al. and Surbeck [45, 46]. Ra disks are commercially available from nucfilm [47]. For uranium, there also exists a selective surface based on diphonix resin supported on polycarbonate [48]. Diphonix-coated disks are commercially available

radionuclides from aqueous solutions and are commercially available, was

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

from nucfilm [47]. They work well below activities of 1 Bq/L because of the restricted load capacity. For example, Surbeck suggests analyzing for uranium only

after the elimination of radium by adsorption with a MnO2 disk. Otherwise

uranium, thorium, radium, plutonium and other alpha nuclides [52, 53]. In our laboratory we have experiences in analyzing uranium and thorium in acid extract

solutions of spices [54]. Our method is based on working sheets from the Paul Scherrer Institute (PSI), which describes the production of a homemade electrodeposition unit and the application for the enrichment of uranium or thorium on stainless steel planchettes [51, 55–58]. Frindik et al. give a method for the determination of many alpha nuclides, including such as plutonium and

Alpha nuclides in a liquid milieu can be adsorbed electrolytically onto stainless steel disks (electroplating, electrodeposition). The Mitchell method describes the deposition of actinides (uranium, americium, polonium) in a HCl milieu [50]. The Talvitie method is used for the deposition of actinides (uranium, thorium) in the

For radium, micro-precipitation processes based on manganese dioxide are well used. Many alpha nuclides, such as americium or plutonium, are analyzable. To equalize losses of analytes in the precipitation step, the use of radioactive tracers (internal standards) is important [60]. Thorium, uranium, plutonium, americium

Radionuclides are collected on impregnated filters more or less selectively. Best examples are radium-specific filters from 3 M Empore (Radium Rad disks). 228Ra can be analyzed indirectly via its short-lived daughter 228Ac, which is built on the filter surface by the disintegration of the enriched 228Ra. This is a very interesting

<sup>2</sup> milieu [51]. Many applications were published for

overloading effects with radiumnuclides may be noticed [49].

/SO4

and curium species are analyzable [61, 62].

approach for the analysis of the dose-relevant 228Ra [63, 64].

[36, 37].

published.

presence of a HSO4

americium [59].

4.3.2 Filtration

151

4.3.1 Micro-precipitation

4.3 Adsorptive surfaces

DOI: http://dx.doi.org/10.5772/intechopen.90166

### 4.1 Oxidation of the matrix

There are several common techniques for the preparation of samples. For nonvolatile and thermal stable analytes, solid samples can be calcinated in an oven (dry ashing). For volatile analytes, e.g. 210Po, where losses are possible at temperatures over 200°C or radiocesium (400°C), the matrix can be oxidized with mineral acid/ peroxide in a microwave oven at moderate temperatures around 200°C.

In water samples, the analytes can be concentrated by evaporation or distillation of the water. Other procedures include direct evaporation of the sample on surfaces or by vacuum sublimation (e.g. Frisch-grid ionization chambers or gas proportional counters). The German DIN prescribes the evaporation of the water phase in the presence of barium as a carrier for the analysis of 226Ra. After a second precipitation with sulphate as a cleanup to remove thorium and polonium, the analyte can be measured [17].

### 4.2 Liquid-liquid extraction

Liquid samples can be water samples or aqueous extraction solutions of solid samples. They may be extracted with nuclide-specific, extractive cocktails. Jack McDowell et al. have developed a set of extractants/fluors for different alpha nuclides [18]. Some special applications with the photon electron rejection alpha liquid spectrometry (PERALS) system are described in [19–21]. For the extraction of uranium with the extractor/scintillator URAEX, several investigations to optimize analytical procedures were published [22–24]. Véronneau et al. [25] investigated the extraction of polonium with different extractors/scintillators. Our preferred system is PPBO<sup>1</sup> /TOPO<sup>2</sup> , commercially available as POLEX™. The PERALS system combined with a set of specific extractant/scintillator is a powerful analytical tool for the analysis of alpha nuclides (Table 3) [27].


### Table 3.

Extractant/fluor solutions for PERALS-α-spectrometry [26].

<sup>1</sup> 2-(4<sup>0</sup> -biphenylyl)-6-phenylbenzoxazole

<sup>2</sup> Trioctylphosphine oxide

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

Many other extraction systems were published. For example, Leeuwen et al. published an overview on the selective extraction of radium with means of chelators [36, 37].

### 4.3 Adsorptive surfaces

one must eliminate the matrix without losing the alpha nuclides. The following survey is not a complete review of the commonly used techniques. It is more focused on the applied procedures at the state laboratory of Basel City. This focus

There are several common techniques for the preparation of samples. For nonvolatile and thermal stable analytes, solid samples can be calcinated in an oven (dry ashing). For volatile analytes, e.g. 210Po, where losses are possible at temperatures over 200°C or radiocesium (400°C), the matrix can be oxidized with mineral acid/

In water samples, the analytes can be concentrated by evaporation or distillation of the water. Other procedures include direct evaporation of the sample on surfaces or by vacuum sublimation (e.g. Frisch-grid ionization chambers or gas proportional counters). The German DIN prescribes the evaporation of the water phase in the presence of barium as a carrier for the analysis of 226Ra. After a second precipitation with sulphate as a cleanup to remove thorium and polonium, the analyte can be

Liquid samples can be water samples or aqueous extraction solutions of solid samples. They may be extracted with nuclide-specific, extractive cocktails. Jack McDowell et al. have developed a set of extractants/fluors for different alpha nuclides [18]. Some special applications with the photon electron rejection alpha liquid spectrometry (PERALS) system are described in [19–21]. For the extraction of uranium with the extractor/scintillator URAEX, several investigations to optimize analytical procedures were published [22–24]. Véronneau et al. [25] investigated the extraction of polonium with different extractors/scintillators. Our

PERALS system combined with a set of specific extractant/scintillator is a powerful

Reagent Extractable radionuclides Literature data ALPHAEX U, Th, Pa, Hf, Zr, Pu (IV) 23, 28 POLEX Specific for 210Po, 237Np 25, 29, 30 RADONS Specific for 222Rn 31 RADAEX 226Ra (and daughters) 20, 21, 29, 32 STRONEX Specific for 90Sr 33 THOREX 228Th, 230Th, 232Th and Zr, Hf, U, Eu, In and other nuclides 34, 35 URAEX Specific for 234U and 238U 21, 23, 24

, commercially available as POLEX™. The

/TOPO<sup>2</sup>

analytical tool for the analysis of alpha nuclides (Table 3) [27].

Extractant/fluor solutions for PERALS-α-spectrometry [26].


allows us to report from our long-time experience in alpha spectrometry.

peroxide in a microwave oven at moderate temperatures around 200°C.

4.1 Oxidation of the matrix

Ionizing and Non-ionizing Radiation

measured [17].

4.2 Liquid-liquid extraction

preferred system is PPBO<sup>1</sup>

Table 3.

<sup>1</sup> 2-(4<sup>0</sup>

150

<sup>2</sup> Trioctylphosphine oxide

The use of some specific active surfaces, which are suitable for the adsorption of radionuclides from aqueous solutions and are commercially available, was published.

Such selective phases can be made of pure metals, such as copper, nickel or silver. 210Po will auto adsorb on such a surface in an acidic, reductive milieu using ascorbic acid or hydroxylamine [38–41]. For recovery control of the adsorption process, polonium-208 (208Po) or polonium-209 (209Po) can be added as tracers.

Manganese dioxide-coated surfaces adsorb radium nuclides selectively. Based on the work of Moore and Reid [42], Glöbel and Berlich [43] and Surbeck [44], robust procedures for the analysis of radium in water were developed by Eikenberg et al. and Surbeck [45, 46]. Ra disks are commercially available from nucfilm [47].

For uranium, there also exists a selective surface based on diphonix resin supported on polycarbonate [48]. Diphonix-coated disks are commercially available from nucfilm [47]. They work well below activities of 1 Bq/L because of the restricted load capacity. For example, Surbeck suggests analyzing for uranium only after the elimination of radium by adsorption with a MnO2 disk. Otherwise overloading effects with radiumnuclides may be noticed [49].

Alpha nuclides in a liquid milieu can be adsorbed electrolytically onto stainless steel disks (electroplating, electrodeposition). The Mitchell method describes the deposition of actinides (uranium, americium, polonium) in a HCl milieu [50]. The Talvitie method is used for the deposition of actinides (uranium, thorium) in the presence of a HSO4 /SO4 <sup>2</sup> milieu [51]. Many applications were published for uranium, thorium, radium, plutonium and other alpha nuclides [52, 53]. In our laboratory we have experiences in analyzing uranium and thorium in acid extract solutions of spices [54]. Our method is based on working sheets from the Paul Scherrer Institute (PSI), which describes the production of a homemade electrodeposition unit and the application for the enrichment of uranium or thorium on stainless steel planchettes [51, 55–58]. Frindik et al. give a method for the determination of many alpha nuclides, including such as plutonium and americium [59].

### 4.3.1 Micro-precipitation

For radium, micro-precipitation processes based on manganese dioxide are well used. Many alpha nuclides, such as americium or plutonium, are analyzable. To equalize losses of analytes in the precipitation step, the use of radioactive tracers (internal standards) is important [60]. Thorium, uranium, plutonium, americium and curium species are analyzable [61, 62].

### 4.3.2 Filtration

Radionuclides are collected on impregnated filters more or less selectively. Best examples are radium-specific filters from 3 M Empore (Radium Rad disks). 228Ra can be analyzed indirectly via its short-lived daughter 228Ac, which is built on the filter surface by the disintegration of the enriched 228Ra. This is a very interesting approach for the analysis of the dose-relevant 228Ra [63, 64].

### 5. Measurement equipment

For a general survey, we recommend the Handbook of Radioactivity Analyses [65]. Another somewhat older standard book is Radiation Detection and Measurement from Knoll [66]. In this chapter, we describe the most used analytical techniques for alpha nuclides as we know.

### 5.1 Alpha particle spectrometry

Passivated implanted planar silicon detectors (PIPS) or silicon barrier detectors are widely used in analyzing alpha nuclides. It is necessary to obtain thin, homogenous alpha sources. Thick sources show broad peaks due to some degradation cause by self-adsorption. High-resolution alpha spectrometry needs thin sources. For this purpose, stainless steel plates or adsorptive surfaces are ideal. Very thin micro precipitates are also suitable. Most alpha nuclides are energy resolved, with one exception. The alpha energies of plutonium-239 (239Pu) and plutonium-240 (240Pu) differ only 10 keV. They may not be resolved in the alpha spectrum and therefore often given as the activity sum of both nuclides.

Detector systems are available from Ortec [67] and Mirion (former Canberra) [68]. They are available as multichamber systems to handle the long counting times (e.g. 24 hours) in the daily routine. In our laboratory, we use PIPS detectors to detect alpha nuclides of polonium, radium, uranium and thorium (Figure 2).

### 5.2 Liquid alpha scintillation techniques

Liquid scintillation techniques (LSC) with an alpha/beta discrimination possibility are often used [69]. An example is the analyses of radon. Very sensitive analyses of radon in water samples are possible, when the large beta background of the radon daughters 214Bi and 214Pb is discriminated. The consecutive alpha decays of 222Rn, 218Po and 214Po are counted (cross alpha counting) [70]. Three main procedures for the analysis of radon with LSC are possible. The "direct" method consists in mixing of the water with a water immiscible cocktail. The mixture is then counted with LSC. In the indirect method, radon is transferred from the water into the cocktail phase and then analyzed. The third method uses a purging of the radon into a cocktail phase. The simplest and most precise method is the direct method, because only one step in the sample preparation is necessary. Low detection limits are achievable with a small effort in sample preparation (detection limit of about 0.2 Bq/L).

A special alpha scintillation technique is commercially available from ORDELA [26]. The PERALS called alpha spectrometric technique is based on the following procedure. The analyte is extracted with a selective extracting agent, which contains a specific fluor. With the help of the fluor, α-, β- and γ-rays are converted into photons. The β- and γ-photons of the extract solution are discriminated by the use of a pulse shape discriminator. The discrimination is based on the longer relaxation times of alpha decays. The discriminator eliminates the fast-relaxing β- and γ-induced photons. As resolution of the emissions is much poorer than PIPS detectors, nuclide-specific extractions systems must be used. Methods are available for the analysis of polonium, radon, radium, uranium, thorium and other alpha nuclides [18], see 4.2 (Figure 2).

precipitates can be counted. Methods exist for polonium and other alpha emitters. It is also possible to extract and analyze alpha and beta nuclides, e.g. 210Pb and 210Po.

Common equipment for alpha spectrometry. A, PIPS alpha spectrometer with eight counting cells; B, PERALS alpha liquid scintillation counters; C, alpha spectrum of radium in mineral water; D, PERALS spectrum of uranium in san Pellegrino mineral water; E, PIPS alpha spectrum of polonium in a mineral water; F, PERALS

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

DOI: http://dx.doi.org/10.5772/intechopen.90166

Track detectors are used since many years for the measurement of 222Rn in air.

The tracks on an exposed foil produced by alpha particles are counted with a

5.4 Track detectors

spectrum of thorium in a mineral water.

Figure 2.

153

microscope after chemical etching of the foil.

### 5.3 Gas proportional counting

Gas proportional counting is a suitable analyzing technique when equipped with the possibility to separate alpha from beta rays. Loaded planchettes or disks and thin Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

Figure 2.

5. Measurement equipment

Ionizing and Non-ionizing Radiation

niques for alpha nuclides as we know.

often given as the activity sum of both nuclides.

5.2 Liquid alpha scintillation techniques

5.3 Gas proportional counting

152

5.1 Alpha particle spectrometry

For a general survey, we recommend the Handbook of Radioactivity Analyses [65]. Another somewhat older standard book is Radiation Detection and Measurement from Knoll [66]. In this chapter, we describe the most used analytical tech-

Passivated implanted planar silicon detectors (PIPS) or silicon barrier detectors are widely used in analyzing alpha nuclides. It is necessary to obtain thin, homogenous alpha sources. Thick sources show broad peaks due to some degradation cause by self-adsorption. High-resolution alpha spectrometry needs thin sources. For this purpose, stainless steel plates or adsorptive surfaces are ideal. Very thin micro precipitates are also suitable. Most alpha nuclides are energy resolved, with one exception. The alpha energies of plutonium-239 (239Pu) and plutonium-240 (240Pu) differ only 10 keV. They may not be resolved in the alpha spectrum and therefore

Detector systems are available from Ortec [67] and Mirion (former Canberra) [68]. They are available as multichamber systems to handle the long counting times (e.g. 24 hours) in the daily routine. In our laboratory, we use PIPS detectors to detect alpha nuclides of polonium, radium, uranium and thorium (Figure 2).

Liquid scintillation techniques (LSC) with an alpha/beta discrimination possibility are often used [69]. An example is the analyses of radon. Very sensitive analyses of radon in water samples are possible, when the large beta background of the radon daughters 214Bi and 214Pb is discriminated. The consecutive alpha decays of 222Rn, 218Po and 214Po are counted (cross alpha counting) [70]. Three main procedures for the analysis of radon with LSC are possible. The "direct" method consists in mixing of the water with a water immiscible cocktail. The mixture is then counted with LSC. In the indirect method, radon is transferred from the water into the cocktail phase and then analyzed. The third method uses a purging of the radon into a cocktail phase. The simplest and most precise method is the direct method, because only one step in the sample preparation is necessary. Low detection limits are achievable with

a small effort in sample preparation (detection limit of about 0.2 Bq/L).

A special alpha scintillation technique is commercially available from ORDELA [26]. The PERALS called alpha spectrometric technique is based on the following procedure. The analyte is extracted with a selective extracting agent, which contains a specific fluor. With the help of the fluor, α-, β- and γ-rays are converted into photons. The β- and γ-photons of the extract solution are discriminated by the use of a pulse shape discriminator. The discrimination is based on the longer relaxation times of alpha decays. The discriminator eliminates the fast-relaxing β- and γ-induced photons. As resolution of the emissions is much poorer than PIPS detectors, nuclide-specific extractions systems must be used. Methods are available for the analysis of polonium, radon, radium, uranium, thorium and other alpha nuclides [18], see 4.2 (Figure 2).

Gas proportional counting is a suitable analyzing technique when equipped with the possibility to separate alpha from beta rays. Loaded planchettes or disks and thin

Common equipment for alpha spectrometry. A, PIPS alpha spectrometer with eight counting cells; B, PERALS alpha liquid scintillation counters; C, alpha spectrum of radium in mineral water; D, PERALS spectrum of uranium in san Pellegrino mineral water; E, PIPS alpha spectrum of polonium in a mineral water; F, PERALS spectrum of thorium in a mineral water.

precipitates can be counted. Methods exist for polonium and other alpha emitters. It is also possible to extract and analyze alpha and beta nuclides, e.g. 210Pb and 210Po.

### 5.4 Track detectors

Track detectors are used since many years for the measurement of 222Rn in air. The tracks on an exposed foil produced by alpha particles are counted with a microscope after chemical etching of the foil.

### 5.5 Gamma-ray spectrometry

Gamma-ray spectrometry is only suitable for the analyses of alpha nuclides in samples, where the analytes are present in higher activities (soil, sediments, etc.). Uranium, for example, is only detectable via its daughter nuclides (e.g. 234Th for 238U). Therefore, it is important to render data plausible according to the individual decay time within the decay chains. Radionuclides, which are in secular equilibrium, should show equal activities. Interferences may pretend excessive activities.

Radionuclide Half-life Alpha energies (MeV), %

DOI: http://dx.doi.org/10.5772/intechopen.90166

231Pa 3.28 104 y 4.762,5 (1,8)

224Ra 3.66 d 5.547,9 (5,3)

226Ra 1600 y 4.684,0 (5,95)

228Th 1.91 y 5.520 (73,4)

230Th 7.54 104 y 4.620,5 (23,4)

234U 2.45 105 y 4.804,5 (28,4)

235U 7.04 10<sup>8</sup> y 4.441,7 (18,8)

238U 4.47 109 y 4.220,2 (22,3)

239Pu 2.41 104 y 5.192,8 (11,9)

240Pu 6561 y 5.210,5 (27,2)

241Am 432.4 y 5.479,3 (1,7)

244Cm 18.1 y 5.858,9 (23,3)

Radionuclide decay energies and common detection methods.

Taken from: [1].

Table 4.

155

y

232Th 1.41 1010

branching

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

210Pb 22.3 y beta LSC

210Po 138.4 d 5.407,5 (100) LSC: PERALS

4.795,4 (1,2) 4.819,8 (8,4) 4.939,1 (1,4) 5.023,0 (2,9)

5.788,9 (94,7)

4.870,5 (94,0)

228Ra 5.75 y beta LSC

220Rn 55.6 s 6.404,7 (100) PIPS: PERALS 222Rn 3.83 d 5.590,3 (100) LSC: several specific methods

5.436 (26,0)

4.687,0 (76,3)

4017,8 (21,0) 4081,6 (78,9)

4.857,6 (71,4)

4.474,0 (7,25)

4.269,7 (77,5)

5.231,5 (17,1) 5.244,5 (70,8)

5.255,8 (72,7)

5.534,9 (13,2) 5.578,3 (84,5)

5.901,7 (76,7)

Common methods comments

Gas prop. Counter: indirect via 210Bi Gamma spectrometry: weak line at 46.5 keV

PIPS: Ag and Cu disk

PIPS: electrodeposition Gamma spectrometry

LSC: PERALS PIPS: electrodeposition PIPS: MnO2 disk Gamma spectrometry

LSC: PERALS PIPS: electrodeposition PIPS: MnO2 disk Gamma spectrometry: interfering line at 86 keV

Gamma spectrometry: via 228Ac

LSC: PERALS B: electrodeposition

LSC: PERALS PIPS: electrodeposition

LSC: PERALS PIPS: electrodeposition

LSC: PERALS and others PIPS Gamma spectrometry (indirect)

> LSC: PERALS and others Gamma spectrometry

LSC: PERALS and others PIPS Gamma spectrometry (indirect)

> LSC: PERALS PIPS

> > PIPS

LSC: PERALS PIPS Gamma spectrometry

> LSC: PERALS PIPS

A second challenge is the weak photon emissions of alpha nuclides. In addition, these emissions are in the lower keV range, and the correlation to a specific radionuclide is often doubtful because of interferences. 232Th is such a radionuclide with a main emission line at 63.8 keV. It can easily be mixed with 234Th (63.3 keV). Such lines of weak intensity need counting times of days to get reasonable signals [71]. In drinking water analysis, there are two important radionuclides, 228Ra and 210Pb, which are beta emitters and cause dominant dose contributions. 228Ra can be analyzed indirectly via its short-lived beta daughter 228Ac. 210Pb shows only a very weak line at 46.5 keV. The analysis is only suitable with a germanium detector equipped with a beryllium or carbon window that allows the transmission of lowenergy lines. For both radionuclides, counting times are days or weeks.

226Ra can be analyzed directly with its emission line at 186.21 keV (3.56% emission probability) but which interferes with a more intensive gamma line of 235U (185.72 keV, 57.2%). Here, it is advisable to quantify 226Ra via its daughter nuclides ( 214Bi and 214Pb), after the radioactive equilibrium is established. 228Th and 224Ra are alpha nuclides of the 232Th decay chain. Their activities are calculated via the daughter nuclides (212Pb, 212Bi). 238U may be analyzed via its daughter 234Th. As mentioned before, these radionuclides are only quantifiable in samples, which show relatively high activities (e.g. soil samples) [71]. In Table 4, radionuclide decay energies and common detection methods are listed. Passivated implanted planar silicon detectors (PIPS), liquid scintillation alpha/beta-counting and PERALS are commonly used analytical methods.

### 6. Applications

In this chapter, some few applications of alpha spectrometry for the examination of drinking water and food samples are described. In our laboratory, the main application of alpha spectrometry is for the routine control of water samples, e.g. tap water or mineral waters. Fish and seafood, spices and healing earths are food categories, which may have incorporated relevant quantities of alpha nuclides.

### 6.1 Monitoring of mineral waters from the Swiss market

Natural mineral water should be water of good microbiological quality. It is collected in groundwater layers or rock formations. This water reaches the surface by one or several naturally or artificially built exit points and can be collected there. Mineral waters are classified according to their mineral contents (from very low mineral content to high mineral content) or specified for a dominant constituent (e.g. rich in magnesium, iron, fluoride). Another classification respects the content of carbonic acid (non-carbonated water, sparkling water, etc.). In all cases, minimum or maximum concentrations are defined in the Swiss Ordinance on Beverages [72] and other ordinances. Radionuclide activities in mineral waters may vary in a wide range and are caused by complex solubility and transport processes in the aquifer. The hydrogeological conditions, the uranium and thorium content of the


### Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

### Table 4.

Radionuclide decay energies and common detection methods.

5.5 Gamma-ray spectrometry

Ionizing and Non-ionizing Radiation

commonly used analytical methods.

6. Applications

(

154

Gamma-ray spectrometry is only suitable for the analyses of alpha nuclides in samples, where the analytes are present in higher activities (soil, sediments, etc.). Uranium, for example, is only detectable via its daughter nuclides (e.g. 234Th for 238U). Therefore, it is important to render data plausible according to the individual decay time within the decay chains. Radionuclides, which are in secular equilibrium, should show equal activities. Interferences may pretend excessive activities. A second challenge is the weak photon emissions of alpha nuclides. In addition, these emissions are in the lower keV range, and the correlation to a specific radionuclide is often doubtful because of interferences. 232Th is such a radionuclide with a main emission line at 63.8 keV. It can easily be mixed with 234Th (63.3 keV). Such lines of weak intensity need counting times of days to get reasonable signals [71]. In drinking water analysis, there are two important radionuclides, 228Ra and 210Pb, which are beta emitters and cause dominant dose contributions. 228Ra can be analyzed indirectly via its short-lived beta daughter 228Ac. 210Pb shows only a very weak line at 46.5 keV. The analysis is only suitable with a germanium detector equipped with a beryllium or carbon window that allows the transmission of low-

energy lines. For both radionuclides, counting times are days or weeks.

226Ra can be analyzed directly with its emission line at 186.21 keV (3.56% emission probability) but which interferes with a more intensive gamma line of 235U (185.72 keV, 57.2%). Here, it is advisable to quantify 226Ra via its daughter nuclides

214Bi and 214Pb), after the radioactive equilibrium is established. 228Th and 224Ra are alpha nuclides of the 232Th decay chain. Their activities are calculated via the daughter nuclides (212Pb, 212Bi). 238U may be analyzed via its daughter 234Th. As mentioned before, these radionuclides are only quantifiable in samples, which show relatively high activities (e.g. soil samples) [71]. In Table 4, radionuclide decay energies and common detection methods are listed. Passivated implanted planar silicon detectors (PIPS), liquid scintillation alpha/beta-counting and PERALS are

In this chapter, some few applications of alpha spectrometry for the examination

of drinking water and food samples are described. In our laboratory, the main application of alpha spectrometry is for the routine control of water samples, e.g. tap water or mineral waters. Fish and seafood, spices and healing earths are food categories, which may have incorporated relevant quantities of alpha nuclides.

Natural mineral water should be water of good microbiological quality. It is collected in groundwater layers or rock formations. This water reaches the surface by one or several naturally or artificially built exit points and can be collected there. Mineral waters are classified according to their mineral contents (from very low mineral content to high mineral content) or specified for a dominant constituent (e.g. rich in magnesium, iron, fluoride). Another classification respects the content of carbonic acid (non-carbonated water, sparkling water, etc.). In all cases, minimum or maximum concentrations are defined in the Swiss Ordinance on Beverages [72] and other ordinances. Radionuclide activities in mineral waters may vary in a wide range and are caused by complex solubility and transport processes in the aquifer. The hydrogeological conditions, the uranium and thorium content of the

6.1 Monitoring of mineral waters from the Swiss market

rock formations, solubility behaviour and other chemical characteristics of the radionuclides are crucial for their presence in the water phase.

Besides tap water, mineral waters are the most consumed beverage in Switzerland. Nearly one billion liters are consumed yearly. Today, about 57% of the mineral waters are from Swiss production. 43% are originated from European countries, such as Italy, France, Germany and others [73]. The consummation of such high quantities of water requires rigorous monitoring. However, the law prescribes the declaration of the mineral contents only. Besides a microbiological survey, the focus is on contaminants from agriculture, industry and other productions. In past years, contaminations were detected sporadically. For example, traces of benzene in a French mineral water, E. coli bacteria in a mineral water infiltrated by contaminated seawater or high amounts of radium or uranium in French and Portuguese products gave reason for small scandals and violations of the law. Increased uranium activities in groundwater, originating from the intensive use of phosphate fertilizers, gave reason for the establishing of a monitoring programme for drinking water plants in Germany.

Natural and artificial radio contaminants were first monitored systematically in the USA and Germany [74].<sup>3</sup> In Switzerland, first investigations of mineral waters are from 1990. The Federal Office of Public Health mandated the Swiss Paul Scherrer Institute to analyze mineral waters available from the Swiss market [75]. In 2006 and 2007, the state laboratory of Basel City analyzed mineral waters in collaboration with the Office for food safety and veterinary affairs of the state of Basel-Country with the focus on uranium, tritium, radon and heavy metals [76, 77].

In 2018, our laboratory analyzed 46 mineral waters from the Swiss market. It was a complete investigation of natural and artificial radionuclides according to the TBDV [7]. Since 2018, the food law has changed. The former Ordinance of Food Contaminants and Constituents (FIV) was invalidated [3]. Therefore, no more limits exist for radionuclides in mineral waters. Consequently, it was necessary to validate the results according to the guide and limit values of the Swiss drinking water ordinance (Table 1).

Mineral water samples were collected at stores of the city of Basel. 21 products were Swiss mineral waters, followed by 12 mineral waters from Italy, 3 from Serbia and 2 each from Germany and France. Other countries were Fiji islands, Spain, Portugal, Norway, Kosovo and Croatia. The samples were analyzed by using the following sample preparation/measurement scheme (Table 5).

The aim of such investigations is always to estimate internal doses by consumption of the analyzed food category. Therefore, all dose-relevant radionuclides must be analyzed. These are natural radionuclides and anthropogenic radionuclides, such as <sup>3</sup> H, 40K or 241Am. According to TBDV, the total dose is the sum of the individual doses of all natural radionuclides, with the exception of potassium-40 (40K), tritium ( 3 H) and 222Rn with its short-lived daughters. So, uranium, radium, polonium, thorium and lead nuclides are the main nuclides which contribute to the dose. The doses due to the ingestion of individual radionuclides were calculated as follows:

$$\mathbf{D}\_{\mathbf{i}} = \mathbf{c}\_{\mathbf{i}}^{\star} \mathbf{e}\_{\text{ing},\mathbf{i}}{}^{\star} \mathbf{U} \,, \tag{1}$$

ci: Activity concentration of the radionuclide i eing,i: Ingestion factor of radionuclide i [78]

Radionuclide Sample preparation Sample

DOI: http://dx.doi.org/10.5772/intechopen.90166

234U, 238U Extraction with 5 mL of URAEX 500 mL PERALS-α-

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

224Ra, 226Ra Adsorption on MnO2 disk 200 mL PIPS-α-

210Po Adsorption on Ag disk 100 mL PIPS-α-

Extraction with 5 mL of THOREX

LLT cocktail

STRONEX

H Mix with 12 mL of Ultima Gold

90Sr Extraction with 8 ml of

228Ra No sample preparation 1000 mL γ-spectrometry

210Pb Adsorption on Ni disk 200 mL b-gas proportional

222Rn 1:1 mix with Maxilight cocktail 10 mL α-counting with

cients are listed in Table 6.

in Table 7.

157

228Th, 230Th, 232Th

60Co,131I,134Cs 137Cs, 241Am

laboratory of Basel City.

3

Table 5.

U: Consummation rate (720 L for adult persons and year)

The sum of these individual doses is defined as indicative dose. The dose coeffi-

Sample preparation and analyzing techniques used for the investigation of mineral waters at the state

volume

Analytical technique

spectrometry

spectrometry

(via 228Ac)

spectrometry

counter

spectrometry

LSC

LSC

LSC

500 mL PERALS-α-

8 mL β-counting with

1000 mL β-counting with

No sample preparation 1000 mL γ-spectrometry 0.05–0.1 Bq/L

Quantification limit

4 mBq/L

2 mBq/L

50 mBq/L

5 mBq/L

50 mBq/L

2 mBq/L

0.4 Bq/L

2 Bq/L

0.05 Bq/L

Results of the monitoring of mineral water in Switzerland in 2018 are presented

Uranium was detectable in 45 of 46 mineral waters. The mean activities were

concentration was 1.9 2.0 μg U/L, fulfilling the limit value of 30 μg/L. The ratio of 238U/234U of 1.04 shows an undisturbed equilibrium between the two uranium nuclides. The Italian mineral waters San Pellegrino and Varanina contained 183 and

0.02 0.02 rsp. 0.02 0.03 for 234U and 238U. The corresponding chemical

269 mBq/L of both uranium nuclides, corresponding to 7.0 rsp. 10.6 μg/L. 228Ra is the dominant radionuclide of the radium species. Eleven samples showed activities of 228Ra with a mean of 0.07 0.05 Bq/L. 224Ra and 226Ra were only found in traces (mean 0.04 Bq/L for 226Ra) with one exception. Pedras Salgadas, a mineral water from Portugal, showed an activity of 1.4 Bq/L of 226Ra. Here, the guide value of 0.5 Bq/l was violated. Before 2017, this mineral water was banned from the Swiss market due to the then existing limit value of 1 Bq/L for liquid food. 224Ra was only detected in two samples (<0.002–0.10 Bq/L). 210Pb and 210Po are built at the end of the decay chain of 238U. 210Pb has a relatively long half-life of 22.3 years and is the mother nuclide of 210Bi and 210Po. It is a beta nuclide and commits to the indicative dose. 210Po is an alpha nuclide with a high alpha energy of 5.3 MeV and a half-life of 138 days. Therefore, it is also doserelevant. Fourteen mineral water samples showed a measurable activity of 210Pb.

with

<sup>3</sup> Federal ministry for the environmental conservation, construction and nuclear security (2017). Guidelines on compliance with the requirements of the Drinking Water Ordinance in the testing and evaluation of radioactive substances in drinking water. Drinking water is tested for its concentrations of radioactive substances nationwide.


Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

### Table 5.

rock formations, solubility behaviour and other chemical characteristics of the

Besides tap water, mineral waters are the most consumed beverage in Switzerland. Nearly one billion liters are consumed yearly. Today, about 57% of the mineral waters are from Swiss production. 43% are originated from European countries, such as Italy, France, Germany and others [73]. The consummation of such high quantities of water requires rigorous monitoring. However, the law prescribes the declaration of the mineral contents only. Besides a microbiological survey, the focus is on contaminants from agriculture, industry and other productions. In past years, contaminations were detected sporadically. For example, traces of benzene in a French mineral water, E. coli bacteria in a mineral water infiltrated by contaminated seawater or high amounts of radium or uranium in French and Portuguese products gave reason for small scandals and violations of the law. Increased uranium activities in groundwater, originating from the intensive use of phosphate fertilizers, gave reason for the establishing of a monitoring programme for drinking water

Natural and artificial radio contaminants were first monitored systematically in the USA and Germany [74].<sup>3</sup> In Switzerland, first investigations of mineral waters are from 1990. The Federal Office of Public Health mandated the Swiss Paul Scherrer Institute to analyze mineral waters available from the Swiss market [75]. In 2006 and 2007, the state laboratory of Basel City analyzed mineral waters in collaboration with the Office for food safety and veterinary affairs of the state of Basel-Country with the focus on uranium, tritium, radon and heavy metals [76, 77]. In 2018, our laboratory analyzed 46 mineral waters from the Swiss market. It was a complete investigation of natural and artificial radionuclides according to the TBDV [7]. Since 2018, the food law has changed. The former Ordinance of Food Contaminants and Constituents (FIV) was invalidated [3]. Therefore, no more limits exist for radionuclides in mineral waters. Consequently, it was necessary to validate the results according to the guide and limit values of the Swiss drinking

Mineral water samples were collected at stores of the city of Basel. 21 products were Swiss mineral waters, followed by 12 mineral waters from Italy, 3 from Serbia and 2 each from Germany and France. Other countries were Fiji islands, Spain, Portugal, Norway, Kosovo and Croatia. The samples were analyzed by using the

The aim of such investigations is always to estimate internal doses by consumption of the analyzed food category. Therefore, all dose-relevant radionuclides must be analyzed. These are natural radionuclides and anthropogenic radionuclides, such

H, 40K or 241Am. According to TBDV, the total dose is the sum of the individual doses of all natural radionuclides, with the exception of potassium-40 (40K), tritium

Di ¼ ci\*eing;i\*U, (1)

H) and 222Rn with its short-lived daughters. So, uranium, radium, polonium, thorium and lead nuclides are the main nuclides which contribute to the dose. The doses due to the ingestion of individual radionuclides were calculated as follows:

<sup>3</sup> Federal ministry for the environmental conservation, construction and nuclear security (2017). Guidelines on compliance with the requirements of the Drinking Water Ordinance in the testing and evaluation of radioactive substances in drinking water. Drinking water is tested for its concentrations of

following sample preparation/measurement scheme (Table 5).

radionuclides are crucial for their presence in the water phase.

plants in Germany.

Ionizing and Non-ionizing Radiation

water ordinance (Table 1).

as <sup>3</sup>

with

radioactive substances nationwide.

( 3

156

Sample preparation and analyzing techniques used for the investigation of mineral waters at the state laboratory of Basel City.

ci: Activity concentration of the radionuclide i

eing,i: Ingestion factor of radionuclide i [78]

U: Consummation rate (720 L for adult persons and year)

The sum of these individual doses is defined as indicative dose. The dose coefficients are listed in Table 6.

Results of the monitoring of mineral water in Switzerland in 2018 are presented in Table 7.

Uranium was detectable in 45 of 46 mineral waters. The mean activities were 0.02 0.02 rsp. 0.02 0.03 for 234U and 238U. The corresponding chemical concentration was 1.9 2.0 μg U/L, fulfilling the limit value of 30 μg/L. The ratio of 238U/234U of 1.04 shows an undisturbed equilibrium between the two uranium nuclides. The Italian mineral waters San Pellegrino and Varanina contained 183 and 269 mBq/L of both uranium nuclides, corresponding to 7.0 rsp. 10.6 μg/L.

228Ra is the dominant radionuclide of the radium species. Eleven samples showed activities of 228Ra with a mean of 0.07 0.05 Bq/L. 224Ra and 226Ra were only found in traces (mean 0.04 Bq/L for 226Ra) with one exception. Pedras Salgadas, a mineral water from Portugal, showed an activity of 1.4 Bq/L of 226Ra. Here, the guide value of 0.5 Bq/l was violated. Before 2017, this mineral water was banned from the Swiss market due to the then existing limit value of 1 Bq/L for liquid food. 224Ra was only detected in two samples (<0.002–0.10 Bq/L).

210Pb and 210Po are built at the end of the decay chain of 238U. 210Pb has a relatively long half-life of 22.3 years and is the mother nuclide of 210Bi and 210Po. It is a beta nuclide and commits to the indicative dose. 210Po is an alpha nuclide with a high alpha energy of 5.3 MeV and a half-life of 138 days. Therefore, it is also doserelevant. Fourteen mineral water samples showed a measurable activity of 210Pb.


The mean was 0.10 0.06 Bq/L. The Pedras Salgadas mineral water contained 0.3 Bq/L and therefore was over the guidance value of 0.2 Bq/L. Fourteen mineral water samples contained 210Po in low activities (mean: 0.04 0.06 Bq/L). In an Italian mineral water, the guidance limit of 0.1 Bq/L was overridden (0.23 Bq/L). Thorium nuclides were found in low activities but in almost all mineral waters.

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

The mean sum of the three nuclides was 0.01 Bq/L. These low activities are explained with the insolubility of thorium in water. Thorium species bind mainly on particles or co-precipitate with minerals and are therefore removed from the

222Rn was found in 27 of the 46 samples with a low, mean activity of

radon is constantly produced by the disintegration of 226Ra.

Artificial radionuclides, such as <sup>3</sup>

DOI: http://dx.doi.org/10.5772/intechopen.90166

the detection limits in the groundwater phase.

these higher doses (Figure 3).

6.2 Analysis of healing earths

1.3 1.4 Bq/L (0.4–4.4 Bq/L). Most of the radon is lost during the production and transport of the mineral waters, except the Portuguese Pedras Salgadas, where

Eight samples contained 0.01 0.01 Bq/L 137Cs. One sample showed traces of 90Sr

and radiostrontium are the main components of the global fallout and fallout from NPP accidents (Chernobyl). Their migration into the soil is a slow process. Therefore, disintegration may be fast enough to reduce the activities to amounts below

The calculated internal doses of the mineral waters (indicative doses) were 0.06 0.60 mSv/a. Most samples fulfilled the guidance value of 0.1 mSv/a. The indicative dose of five mineral waters was over the guidance value. The highest dose was calculated for the Portuguese product Pedras Salgadas. We calculated a dose of 0.46 mSv/a for adult persons. Four other mineral waters showed doses between 0.12 and 0.27 mSv/a. Elevated activities of 226Ra, 228Ra and 210Pb were the cause for

Siliceous earths are widely used in the food industry as a food supplement. They are deposits of the silica shells of diatoms (main constituent of marine phytoplankton). These layers are extracted in mines. Siliceous earths incorporate foreign atoms in the crystal lattice, such as radionuclides of the natural decay series

Results from the investigation of mineral waters on the Swiss market 2018. All data in mBq/L, except indicative

dose (μSv). n: Number of samples with activities over the detection limit (given as ">x mBq/L").

H was detectable in only two samples 1.2 0.9 Bq/L. Radiocesium

H, 90Sr and 137Cs, were detectable in traces.

water phase.

(0.05 Bq/L). <sup>3</sup>

Figure 3.

159

### Table 6.

Ingestion factors of the Swiss radiological protection ordinance [78] based on the ICRP concept. All data in μSv/Bq.


### Table 7.

Results from the monitoring of mineral water in Switzerland.

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

The mean was 0.10 0.06 Bq/L. The Pedras Salgadas mineral water contained 0.3 Bq/L and therefore was over the guidance value of 0.2 Bq/L. Fourteen mineral water samples contained 210Po in low activities (mean: 0.04 0.06 Bq/L). In an Italian mineral water, the guidance limit of 0.1 Bq/L was overridden (0.23 Bq/L).

Thorium nuclides were found in low activities but in almost all mineral waters. The mean sum of the three nuclides was 0.01 Bq/L. These low activities are explained with the insolubility of thorium in water. Thorium species bind mainly on particles or co-precipitate with minerals and are therefore removed from the water phase.

222Rn was found in 27 of the 46 samples with a low, mean activity of 1.3 1.4 Bq/L (0.4–4.4 Bq/L). Most of the radon is lost during the production and transport of the mineral waters, except the Portuguese Pedras Salgadas, where radon is constantly produced by the disintegration of 226Ra.

Artificial radionuclides, such as <sup>3</sup> H, 90Sr and 137Cs, were detectable in traces. Eight samples contained 0.01 0.01 Bq/L 137Cs. One sample showed traces of 90Sr (0.05 Bq/L). <sup>3</sup> H was detectable in only two samples 1.2 0.9 Bq/L. Radiocesium and radiostrontium are the main components of the global fallout and fallout from NPP accidents (Chernobyl). Their migration into the soil is a slow process. Therefore, disintegration may be fast enough to reduce the activities to amounts below the detection limits in the groundwater phase.

The calculated internal doses of the mineral waters (indicative doses) were 0.06 0.60 mSv/a. Most samples fulfilled the guidance value of 0.1 mSv/a. The indicative dose of five mineral waters was over the guidance value. The highest dose was calculated for the Portuguese product Pedras Salgadas. We calculated a dose of 0.46 mSv/a for adult persons. Four other mineral waters showed doses between 0.12 and 0.27 mSv/a. Elevated activities of 226Ra, 228Ra and 210Pb were the cause for these higher doses (Figure 3).

### 6.2 Analysis of healing earths

Siliceous earths are widely used in the food industry as a food supplement. They are deposits of the silica shells of diatoms (main constituent of marine phytoplankton). These layers are extracted in mines. Siliceous earths incorporate foreign atoms in the crystal lattice, such as radionuclides of the natural decay series

### Figure 3.

Radionuclide Infants (1–2 years) Children > 10 years Adult persons Americium-241 (241Am) 0.37 0.22 0.20 Lead-210 (210Pb) 3.6 1.9 0.69 Cesium-134 (134Cs) 0.016 0.014 0.019 Cesium-137 (137Cs) 0.012 0.010 0.013 Iodine-131 (131I) 0.180 0.052 0.022 Cobalt-60 (60Co) 0.027 0.011 0.003 Polonium-210 (210Po) 8.8 2.6 1.2 Radium-224 (224Ra) 0.66 0.26 0.065 Radium-226 (226Ra) 0.96 0.80 0.28 Radium-228 (228Ra) 1.70 1.70 1.70 Radon (222Rn) 0.02 0.02 0.01 Strontium-90 (90Sr) 0.073 0.06 0.028 Thorium-228 (228Th) 0.37 0.14 0.072 Thorium-230 (230Th) 0.41 0.24 0.21 Thorium-232 (232Th) 0.45 0.29 0.23

H) 4.8E 11 2.3E 11 1.8E 11

Strontium-90 (90Sr) 0.073 0.06 0.028 Uranium-238 (238U) 0.12 0.068 0.045 Uranium-234 (234U) 0.13 0.074 0.049

Ingestion factors of the Swiss radiological protection ordinance [78] based on the ICRP concept. All data in

Radionuclide Mean s.d. Min Max n 234U Bq/L 0.02 0.02 0.002 0.14 45 238U Bq/L 0.02 0.03 0.002 0.13 45 natU <sup>μ</sup>g/L 1.9 2.0 0.1 10.6 45 224Ra Bq/L 0.003 0.02 0.002 0.11 <sup>2</sup> 226Ra Bq/L 0.04 0.21 0.002 1.4 <sup>23</sup> 228Ra Bq/L 0.07 0.05 0.05 0.44 11 222Rn Bq/L 1.3 1.4 0.4 4.4 <sup>27</sup> 210Po Bq/L 0.04 0.06 0.01 0.23 14 210Pb Bq/L 0.10 0.06 0.05 0.27 14 228Th Bq/L 0.003 0.002 0.002 0.01 22 230Th Bq/L 0.002 0.002 0.002 0.01 12 232Th Bq/L 0.003 0.004 0.002 0.02 20

s.d., standard deviation; n, number of positive samples from a total of 46 samples.

Results from the monitoring of mineral water in Switzerland.

Tritium (3

Ionizing and Non-ionizing Radiation

Table 6.

μSv/Bq.

Table 7.

158

Results from the investigation of mineral waters on the Swiss market 2018. All data in mBq/L, except indicative dose (μSv). n: Number of samples with activities over the detection limit (given as ">x mBq/L").


s.d.: standard deviation.

\* Number of positive samples/total of samples.

All data in Bq/kg dry weight and from [78, 79].

### Table 8.

Investigation of healing earths on the Swiss market.

of uranium and thorium. In 2008, the state laboratory of Basel City analyzed siliceous earth products on the Swiss market with α- and γ-spectrometry. In two products, the limit values for 226Ra and 210Po were exceeded (>50Bq/kg). Furthermore, the annual dose by regular consummation of one product from California, USA, reached 0.5 mSv, half of the permitted yearly dose (1mSv). Consequently, this product was withdrawn from the Swiss market [79]. In 2010, a second inspection of the healing earths on the Swiss market showed that two products from German production slightly exceeded the limit values of 226Ra and 228Ra. The calculated, annual doses of these products when regularly consumed reached 0.1mSv/year [80]. Finally, we noted that healing earths can lead to doses up to 0.5 mSv. At last, materials based on silica for industrial use (e.g. as adsorbents or filter media in a chemical laboratories) can lead to the contamination of the environment when such materials are disposed or burnt (Table 8).

### 6.3 Radiological investigation of spices

Radionuclides from the uranium and thorium series may be enriched in plants and therefore also in spices. Until 2017, Swiss legislation included limit values for natural radionuclides in spices. For radionuclides of the group I (224Ra, 228Th, 234U, 235U, 238U), a cumulative limit value of 500 Bq/kg was given in the Ordinance of Contaminants and Constituents in Food [3]. For group II (210Pb, 210Po, 226Ra, 228Ra, 230Th, 232Th and 231Pa), a cumulative limit value of 50 Bq/kg was defined.

reached 10–32% of the limit value (500 Bq/kg). The cumulated activity of the radionuclides of group II, especially 226Ra and 228Ra, reached 10–26% of the limit value (50 Bq/kg) (Table 9). The consummation of 100 g of pepper in a year leads to

Radionuclide Mean s.d. Samples\* Min Max

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

224Ra 8.2 6.0 5/8 2.0 <sup>16</sup> 226Ra 3.4 0.89 5/8 2.0 4.0 228Ra 9.7 7.1 6/8 3.3 <sup>23</sup> 228Th 0.9 0.37 3/3 0.51 1.25 230Th 3.0 0.72 1/3 3.0 3.0 232Th 3.0 3.1 2/3 0.77 5.3

224Ra 2.0 0.5 1/12 2.0 2.0 226Ra 2.1 0.61 3/12 1.6 2.8

228Th 1.1 0.85 5/5 0.27 2.4 230Th 0.3 0.08 1/5 0.33 0.33 232Th 1.1 0.79 5/5 0.37 2.5

226Ra 3.1 1.7 3/11 2.0 5.0 228Ra 3.3 1.7 1/11 3.3 3.3 228Th 1.3 0.8 6/11 0.32 2.5 230Th 0.4 0.17 3/11 0.21 0.52 232Th 1.0 0.52 6/11 0.23 1.8

Natural radionuclides cause the main radio contamination of fish and seafood. Mussels and molluscs may enrich 210Po in the intestinal tract, whereas the mother nuclide 210Pb is not enriched [82]. Activity concentrations of 210Po range from 20 to

In 1998, we investigated the contamination of 210Po in sea fish and mussels. The 210Po was extracted with acid and microwaves at temperatures below 200°C. Then, the analytes (210Po and internal standard 209Po) were adsorbed onto silver disks by autodeposition in an alkaline milieu. The disks were counted with alpha PIPS

We had to declare objections for 12 mussel and 2 fish samples (sardines). Sardines showed elevated activity of 210Po. They are consumed as the whole fish, the

100 Bq/kg. In fish, the 210Po level is much lower (1–20 Bq/kg) [83].

a dose of about 1–2 μSv [54, 81].

Pepper

Paprika

Curries

s.d.: Standard deviation.

All data from [53, 80].

\*

161

Table 9.

228Ra <2

DOI: http://dx.doi.org/10.5772/intechopen.90166

224Ra <2

Number of positive samples/total of samples

Investigation of spices on the Swiss market.

6.4 Analysis of seafood and fish

detectors for 24 hours (Table 10).

A total of 50 spice samples from Spain, South Africa, Asian countries, Turkey and India were collected on the Swiss market and analyzed with gamma-ray spectrometry. After reaching equilibrium between 226Ra and 222Rn (20 days), 226Ra was determined via its daughter nuclides 214Bi and 214Pb. 224Ra is in equilibrium with its daughters 212Pb and 212Bi. 228Ra was analyzed via its daughter nuclide 228Ac. The thorium nuclides 228Th, 230Th and 232Th were analyzed with alpha spectrometry using PIPS detectors. The sources were prepared by deposition of the thorium species from acid microwave extracts onto steel disks with electrodeposition.

Pepper samples contained increased amounts of the radium and thorium nuclides. The cumulated activity of the radionuclides from group I, especially 224Ra,


Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

s.d.: Standard deviation.

\* Number of positive samples/total of samples

All data from [53, 80].

### Table 9.

of uranium and thorium. In 2008, the state laboratory of Basel City analyzed siliceous earth products on the Swiss market with α- and γ-spectrometry. In two products, the limit values for 226Ra and 210Po were exceeded (>50Bq/kg). Furthermore, the annual dose by regular consummation of one product from California, USA, reached 0.5 mSv, half of the permitted yearly dose (1mSv). Consequently, this product was withdrawn from the Swiss market [79]. In 2010, a second inspection of the healing earths on the Swiss market showed that two products from German production slightly exceeded the limit values of 226Ra and 228Ra. The calculated, annual doses of these products when regularly consumed reached 0.1mSv/year [80]. Finally, we noted that healing earths can lead to doses

Radionuclide Mean s.d. Samples\* Min Max 224Ra 25.3 21.5 30/32 1.7 <sup>63</sup> 226Ra 42.1 33.6 30/32 2.9 <sup>133</sup> 228Ra 27.2 23.5 30/32 2.0 <sup>67</sup> 234U 56.9 29.1 18/26 15.4 <sup>115</sup> 235U 4.0 2.1 07/26 1.5 6.9 238U 75.4 56.7 22/26 6.5 <sup>227</sup> 227Th 2.6 1.8 17/29 0.7 6.0 210Pb <sup>183</sup> <sup>152</sup> 6/24 <sup>49</sup> <sup>428</sup> 210Po 11.0 9.0 22/24 2.0 <sup>42</sup>

up to 0.5 mSv. At last, materials based on silica for industrial use (e.g. as adsorbents or filter media in a chemical laboratories) can lead to the

230Th, 232Th and 231Pa), a cumulative limit value of 50 Bq/kg was defined.

(Table 8).

160

s.d.: standard deviation.

Number of positive samples/total of samples. All data in Bq/kg dry weight and from [78, 79].

Ionizing and Non-ionizing Radiation

Investigation of healing earths on the Swiss market.

\*

Table 8.

6.3 Radiological investigation of spices

contamination of the environment when such materials are disposed or burnt

Radionuclides from the uranium and thorium series may be enriched in plants and therefore also in spices. Until 2017, Swiss legislation included limit values for natural radionuclides in spices. For radionuclides of the group I (224Ra, 228Th, 234U, 235U, 238U), a cumulative limit value of 500 Bq/kg was given in the Ordinance of Contaminants and Constituents in Food [3]. For group II (210Pb, 210Po, 226Ra, 228Ra,

A total of 50 spice samples from Spain, South Africa, Asian countries, Turkey and India were collected on the Swiss market and analyzed with gamma-ray spectrometry. After reaching equilibrium between 226Ra and 222Rn (20 days), 226Ra was determined via its daughter nuclides 214Bi and 214Pb. 224Ra is in equilibrium with its daughters 212Pb and 212Bi. 228Ra was analyzed via its daughter nuclide 228Ac. The thorium nuclides 228Th, 230Th and 232Th were analyzed with alpha spectrometry using PIPS detectors. The sources were prepared by deposition of the thorium species from acid microwave extracts onto steel disks with electrodeposition. Pepper samples contained increased amounts of the radium and thorium nuclides. The cumulated activity of the radionuclides from group I, especially 224Ra, Investigation of spices on the Swiss market.

reached 10–32% of the limit value (500 Bq/kg). The cumulated activity of the radionuclides of group II, especially 226Ra and 228Ra, reached 10–26% of the limit value (50 Bq/kg) (Table 9). The consummation of 100 g of pepper in a year leads to a dose of about 1–2 μSv [54, 81].

### 6.4 Analysis of seafood and fish

Natural radionuclides cause the main radio contamination of fish and seafood. Mussels and molluscs may enrich 210Po in the intestinal tract, whereas the mother nuclide 210Pb is not enriched [82]. Activity concentrations of 210Po range from 20 to 100 Bq/kg. In fish, the 210Po level is much lower (1–20 Bq/kg) [83].

In 1998, we investigated the contamination of 210Po in sea fish and mussels. The 210Po was extracted with acid and microwaves at temperatures below 200°C. Then, the analytes (210Po and internal standard 209Po) were adsorbed onto silver disks by autodeposition in an alkaline milieu. The disks were counted with alpha PIPS detectors for 24 hours (Table 10).

We had to declare objections for 12 mussel and 2 fish samples (sardines). Sardines showed elevated activity of 210Po. They are consumed as the whole fish, the


All data from [83, 84].

### Table 10.

Investigation of fish and seafood.

intestinal tract included, similar to the consummation of mussels. This explains the higher contamination level in sardines and anchovies. In 2010, the state laboratory of Basel City undertook a second investigation with similar results. Because since 1990 the limit value for 210Po in fish and seafood was raised from 10 to 150 Bq/kg (indeed, the rate of fish and seafood consummation in Switzerland is of minor relevance), no more objections had to be raised [85, 86].

### 7. Conclusions

In the radiation laboratory, where food and environmental samples are investigated, alpha spectrometry is a mandatory part of the instrumentation. Wellestablished analytical procedures exist for the analysis of polonium, radium, uranium, thorium and transuranium nuclides. Suitable radioactive sources are prepared either by co-precipitation, selective extraction or adsorption onto active surfaces. The alpha spectrometric equipment at choice are PIPS detectors, gas proportional detectors and liquid scintillation counters. Drinking water is the most important food. Periodical survey for radioactive contaminants is important to guarantee a secure consummation. Because drinking water sources may underlie seasonal variations of their activity concentrations, they must be reexamined from time to time. The dose-relevant radionuclides in our investigation of mineral waters and tap water were 210Pb, 226Ra and 228Ra.

Author details

Markus Zehringer

163

State-Laboratory Basel-City, Basel, Switzerland

provided the original work is properly cited.

\*Address all correspondence to: markus.zehringer@bs.ch

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis…

DOI: http://dx.doi.org/10.5772/intechopen.90166

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Additionally, there are some food categories, which may show elevated activities of alpha nuclides. Mussels and fish may enrich 210Po in the gastrointestinal tract. When consuming whole fish, such as sardines or anchovies, higher amounts of 210Po are taken up. This can lead to relevant doses, especially in countries where consummation of fish and seafood is a main part of the nutrition. Healing earths may contain higher amounts of 226Ra and 228Ra. In spices, radium species are dominant, while pepper can contain higher amounts of thorium nuclides.

Monitoring of Natural Radioactivity in Drinking Water and Food with Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.90166

### Author details

intestinal tract included, similar to the consummation of mussels. This explains the higher contamination level in sardines and anchovies. In 2010, the state laboratory of Basel City undertook a second investigation with similar results. Because since 1990 the limit value for 210Po in fish and seafood was raised from 10 to 150 Bq/kg (indeed, the rate of fish and seafood consummation in Switzerland is of minor

Radionuclide Mean s.d. Samples\* Min Max

210Po 0.004 0.005 21/ 0.002 0.02 226Ra 3.2 6.3 54/140 0.20 <sup>43</sup> 228Ra 1.3 0.87 22/100 0.40 4.5

210Po 0.02 0.03 18/19 0.001 0.11 226Ra 1.7 1.4 5/19 0.62 4.1 228Ra 0.71 0.44 6/19 0.30 1.3

210Po 0.005 0.013 11/27 0.001 0.05 226Ra 2.0 1.7 12/27 0.30 5.4 228Ra 1.2 0.10 3/27 1.1 1.2

In the radiation laboratory, where food and environmental samples are investi-

Additionally, there are some food categories, which may show elevated activities of alpha nuclides. Mussels and fish may enrich 210Po in the gastrointestinal tract. When consuming whole fish, such as sardines or anchovies, higher amounts of 210Po are taken up. This can lead to relevant doses, especially in countries where consummation of fish and seafood is a main part of the nutrition. Healing earths may contain higher amounts of 226Ra and 228Ra. In spices, radium species are dominant, while pepper can contain higher amounts of thorium nuclides.

gated, alpha spectrometry is a mandatory part of the instrumentation. Wellestablished analytical procedures exist for the analysis of polonium, radium, uranium, thorium and transuranium nuclides. Suitable radioactive sources are prepared either by co-precipitation, selective extraction or adsorption onto active surfaces. The alpha spectrometric equipment at choice are PIPS detectors, gas proportional detectors and liquid scintillation counters. Drinking water is the most important food. Periodical survey for radioactive contaminants is important to guarantee a secure consummation. Because drinking water sources may underlie seasonal variations of their activity concentrations, they must be reexamined from time to time. The dose-relevant radionuclides in our investigation of mineral waters

relevance), no more objections had to be raised [85, 86].

and tap water were 210Pb, 226Ra and 228Ra.

7. Conclusions

162

Fish

Seafood

\*

Table 10.

s.d.: Standard deviation.

All data from [83, 84].

Investigation of fish and seafood.

Number of positive samples/total of samples.

Sardines, anchovies

Ionizing and Non-ionizing Radiation

Markus Zehringer State-Laboratory Basel-City, Basel, Switzerland

\*Address all correspondence to: markus.zehringer@bs.ch

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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pp. 239-243. ISBN: 0-8493-3594-9. Ch. 8

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CRC Taylor & Francis; 2007.

Experiences of the food control authority of Basel-city since the Chernobyl accident. In: Monteiro W, editor. Radiation Effects in Materials. Croatia: InTech; 2016: 132-160. Available from: http://dx.doi.org/

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Wiley & Sons; 1999. ISBN: 0-471-

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[75] Aellen T, Ch W, Görlich W, Umbricht O. Natürliche Radionuklide der Uran- und Thorium Zerfallsreihe in Mineralwässern. In: Federal Office of Public Health, editor. Environmental Radioactivity and Radiation Doses in Switzerland. 1990. Bern: Office of Public Health, B.3.5.10.-16. ISBN: 3-905235-04-8; Available from: https:// www.bag.admin.ch/bag/de/home/dasbag/publikationen/taetigkeitsberich te/jahresberichte-umweltradioaktiviaet.

html [Accessed: May 25, 2019]

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micropollutants, heavy metals and radioactivity in mineral waters. In: Annual Report of the State-Laboratory of Basel-City. 2007. pp. 70-72. Available from: https://www.kantonslabor.bs.ch/ berichte/jahresberichte.html [Accessed

[78] Swiss Federal Council. Radiological protection ordinance (RPO); April 26,

2017. Status: February 1, 2019

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May 25, 2019]

pp. 83-86

May 25, 2019]

May 25, 2019]

[67] Ortec. Available from: http:// www.ortec-online.com/ [Accessed:

[68] Mirion (former Canberra).

Available from: http://www.canberra.c om/products/detectors/ [Accessed:

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[70] Frenzel E, Kossert K, Oikari T, Otto R, Wisser S. Die Messung von 89Sr/90Sr und 90Sr/90Y mittels TDCR-Cerenkov-Zählung.

Strahlenschutzpraxis. 2013;1:26-33

spectrometry and the investigation of environmental and food samples. In: Maghraby A, editor. New Insights on Gamma Rays. Croatia: InTech; 2017. pp. 3-27. ISBN 978-953-51-3162-5

[72] The Federal Department of Home Affairs. Ordinance on Beverages; 2016.

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Trinkwasserverordnung. Empfehlungen von BMUB, BMG, BfS, UBA und den zuständigen Landesbehörden sowie DVGW und BDEW. Available from: h ttps://doris.bfs.de/jspui/bitstream/urn:

(BMUB). 2017. Leitfaden zur Untersuchung und Bewertung von radioaktiven Stoffen im Trinkwasser

nbn:de:0221-2017020114224/5/

bei der Umsetzung der

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Status: May 1, 2017

2019]

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81504-7

May 21, 2019]

May 21, 2019]

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[83] Froidevaux P, Dell D, Tossell P. Radionuclides in foodstuffs and food raw material. In: Pöschl M, Nollet L, editors. Radionuclide Concentrations in Food and the Environment. New York: CRC Taylor & Francis; 2007. pp. 239-243. ISBN: 0-8493-3594-9. Ch. 8

[84] Zehringer M. Radioactivity in food: Experiences of the food control authority of Basel-city since the Chernobyl accident. In: Monteiro W, editor. Radiation Effects in Materials. Croatia: InTech; 2016: 132-160. Available from: http://dx.doi.org/ 10.5772/62460

[85] Zehringer M. Gamma nuclides, polonium-210 and heavy metal traces in fish and seafood. In: Annual Report of the State-Laboratory of Basel-City. 2010. pp. 57-59. Available from: https:// www.kantonslabor.bs.ch/berichte/jahre sberichte.html [Accessed May 25, 2019]

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**171**

wild mice

**Chapter 9**

**Abstract**

with the FDNPP accident.

Analysis of Radioactive Elements

in Testes of Large Japanese

Fukushima Accident

Field Mice Using an Electron

Probe Micro-Analyser after the

*Yohei Fujishima, Valerie Swee Ting Goh, Kosuke Kasai,* 

*Kentaro Ariyoshi, Akifumi Nakata, Yusuke Urushihara,* 

*Masatoshi Suzuki, Atsushi Takahasi, Yoshinaka Shimizu,* 

*Hisashi Shinoda, Mitsuaki A. Yoshida, Manabu Fukumoto,* 

The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. The large Japanese field mice (*Apodemus speciosus*) are rodents endemic to, and distributed throughout, Japan. This wild rodent live in and around the ex-evacuation zone on the ground surface and/or underground. In this study, we evaluated the effect of chronic radiation exposure associated with FDNPP accident on the testes of large Japanese field mice. Morphological analysis and electron-prove X-ray microanalysis (EPMA) was undertaken on the testes. Morphological analysis of testes based on H&E staining showed that the spermatogenesis was observed normally in the breeding season of wild mice in the heavily contaminated area. However, caesium (Cs) was not detected in all testes of wild mice from FDNPP ex-evacuation zone. In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, we could not detect radiation effects on the spermatogenesis and Cs in the examined large Japanese field mice testes following chronic radiation exposure associated

**Keywords:** EPMA analysis, Fukushima nuclear power plant accident, testis,

*Kazuma Koarai, Yasushi Kino, Tsutomu Sekine,* 

*Hideaki Yamashiro and Tomisato Miura*

*Takuya Ohdaira, Kanna Meguro, Kazuki Komatsu, Rina Syoji,* 

### **Chapter 9**

## Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe Micro-Analyser after the Fukushima Accident

*Takuya Ohdaira, Kanna Meguro, Kazuki Komatsu, Rina Syoji, Yohei Fujishima, Valerie Swee Ting Goh, Kosuke Kasai, Kentaro Ariyoshi, Akifumi Nakata, Yusuke Urushihara, Kazuma Koarai, Yasushi Kino, Tsutomu Sekine, Masatoshi Suzuki, Atsushi Takahasi, Yoshinaka Shimizu, Hisashi Shinoda, Mitsuaki A. Yoshida, Manabu Fukumoto, Hideaki Yamashiro and Tomisato Miura*

### **Abstract**

The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. The large Japanese field mice (*Apodemus speciosus*) are rodents endemic to, and distributed throughout, Japan. This wild rodent live in and around the ex-evacuation zone on the ground surface and/or underground. In this study, we evaluated the effect of chronic radiation exposure associated with FDNPP accident on the testes of large Japanese field mice. Morphological analysis and electron-prove X-ray microanalysis (EPMA) was undertaken on the testes. Morphological analysis of testes based on H&E staining showed that the spermatogenesis was observed normally in the breeding season of wild mice in the heavily contaminated area. However, caesium (Cs) was not detected in all testes of wild mice from FDNPP ex-evacuation zone. In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, we could not detect radiation effects on the spermatogenesis and Cs in the examined large Japanese field mice testes following chronic radiation exposure associated with the FDNPP accident.

**Keywords:** EPMA analysis, Fukushima nuclear power plant accident, testis, wild mice

### **1. Introduction**

The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. We have established an archive system composed of livestock and wild animals within a 20 km radius from FDNPP, that is, the ex-evacuation zone of the FDNPP accident [1–13]. This system provides critical information for the understanding of environmental pollution, biodistribution, radionuclide metabolism, dose evaluation, and the biological effects of internal and external exposure to radiation caused by nuclear disasters. In particular, experimental studies of low-dose rate (LDR) radiation exposure induced effects on spermatogenesis, along with indications from the nuclear disaster in Fukushima, will provide a more comprehensive radiobiological understanding of response mechanisms leading to improved accuracy in the estimation of human reproduction and health risk [14].

The large Japanese field mice (*Apodemus speciosus*) are rodents endemic to, and distributed throughout, Japan [15]. This wild rodent is appropriate for use as a reference animal of the ecosystem. Large Japanese field mice live in and around the ex-evacuation zone on the ground surface and/or underground. Hence, they are exposed to high levels of external radiation. Furthermore, they eat contaminated food and drink contaminated water. Consequently, they are directly affected by radioactive substances. Therefore, these mice can serve as a model to study the effect of radiation exposure, while also serving as a reference animal for the surrounding ecosystem.

Electron probe X-ray microanalysis (EPMA) is a powerful tool used to detect trace amounts of chemical elements in single cells and tissues [16]. This method measures the characteristic X-ray spectra of specific elements in samples using an accelerated electron beam. We previously investigated the effect of chronic LDR exposure to 134Cs and 137Cs on the testis of euthanised bulls, boars, and inobutas from the evacuation zone [3, 7].

Discharge of 134Cs and 137Cs that emit γ- and β-rays is of primary concern, because they were released in a large amount and have a long half-life. In this study, we evaluated the heavy contamination levels of LDR effects of 134Cs and 137Cs (between 4848 and 70,200 Bq/kg) on the large Japanese field mice after the FDNPP accident.

### **2. Materials and methods**

### **2.1 Collections of large Japanese field mice**

The study protocol followed laboratory animal care guidelines, and all procedures were conducted in accordance with the guideline of the Ethics Committee for Care and Use of Laboratory Animals for Research of Niigata University, Japan (approval number: H2611). Large Japanese field mice were captured using Sherman traps (H.B. Sherman Traps, Inc., Tallahassee, FL, USA) at three sites, Akogi, Ide, and Omaru of Namie town in the ex-evacuation zone of the FDNPP accident in November 2012, April 2013, and April 2016 (**Figure 1**). Control large Japanese mice were captured using Sherman traps in May 2012, November 2015, and April 2016 in Aomori Prefecture, and April and May 2016 in Niigata Prefecture. The ambient dose rate was measured at the sampling sites using NaI (Tl) scintillation survey meter TCS-171B (Hitachi Aloka Medical, Ltd., Tokyo, Japan) at the height of 1 m. The measurements were expressed as micrograys per hour at 1 m above the ground.

**173**

staining.

**Figure 1.**

*Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe…*

Radioactivities of the organ samples were determined via gamma-ray spectrometry using high-purity germanium (HPGe) detector (GEM40P4-83, Ortec Co., Oak Ridge, TN, USA) as described previously [10]. The duration of the measurement varied from 110,600 to 663,400 s, depending on the radioactivity of the sample. Absolute efficiency of the detector was determined with the standard point sources of 137Cs (10 kBq, CS402) and 152Eu (10 kBq, EU402, Japan Isotope Association, Tokyo, Japan). The samples were placed in a small space (1 mm thick and 6 mm diameter) which is the same size as the standard point sources. A nuclide was identified when its characteristic photopeak 3σ above the baseline observed in the spectrum. The activities due to decay were corrected to the sampling dates.

*Sampling site of in Namie town, Niigata and Aomori. Akogi, Ide and Omaru of Namie town in the* 

The testes were fixed in Bouin's solution, embedded in paraffin, and stained using haematoxylin and eosin (H&E), according to standard protocols, as described by Takino et al. [11]. Subsequently, the testes were briefly dehydrated in different concentrations of alcohol. The testes were made transparent by using toluene, and then, then they were embedded in paraffin and cut into 5 μm-thick sections before

Qualitative analysis: An analytical method was used to investigate the composi-

tion of analytical crystal to be used. The analysis conditions were as follows: voltage was set to 15 kV, beam current was 100 nA, beam size was minimum, sample

Elements analysis: Chemical trace analyses of caesium (Cs), sulphur (S), and nitrogen (N) in the testes were performed using a Shimadzu 1720HT electron probe micro-analyser (Shimadzu Corporation, Tokyo, Japan) equipped for X-ray spectrometry and specifically adapted for the examination of ultrathin sections. Accordingly, 3 μm of each testis section was placed on the carbon plate, and

B to 92U can be measured with a combina-

*DOI: http://dx.doi.org/10.5772/intechopen.84634*

**2.2 Measurement of radioactivity**

*ex-evacuation zone of the FDNPP accident is shown in yellow.*

**2.3 Morphological assessment of testes cells**

**2.4 Electron probe X-ray microanalysis**

tion of the sample to be analysed. From <sup>6</sup>

current was 92.8 nA, and time 30 ms/point (**Figure 2**).

*Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe… DOI: http://dx.doi.org/10.5772/intechopen.84634*

**Figure 1.**

*Ionizing and Non-ionizing Radiation*

The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. We have established an archive system composed of livestock and wild animals within a 20 km radius from FDNPP, that is, the ex-evacuation zone of the FDNPP accident [1–13]. This system provides critical information for the understanding of environmental pollution, biodistribution, radionuclide metabolism, dose evaluation, and the biological effects of internal and external exposure to radiation caused by nuclear disasters. In particular, experimental studies of low-dose rate (LDR) radiation exposure induced effects on spermatogenesis, along with indications from the nuclear disaster in Fukushima, will provide a more comprehensive radiobiological understanding of response mechanisms leading to improved accuracy in the estimation of human reproduction

The large Japanese field mice (*Apodemus speciosus*) are rodents endemic to, and distributed throughout, Japan [15]. This wild rodent is appropriate for use as a reference animal of the ecosystem. Large Japanese field mice live in and around the ex-evacuation zone on the ground surface and/or underground. Hence, they are exposed to high levels of external radiation. Furthermore, they eat contaminated food and drink contaminated water. Consequently, they are directly affected by radioactive substances. Therefore, these mice can serve as a model to study the effect of radiation exposure, while also serving as a reference animal for the sur-

Electron probe X-ray microanalysis (EPMA) is a powerful tool used to detect trace amounts of chemical elements in single cells and tissues [16]. This method measures the characteristic X-ray spectra of specific elements in samples using an accelerated electron beam. We previously investigated the effect of chronic LDR exposure to 134Cs and 137Cs on the testis of euthanised bulls, boars, and inobutas

Discharge of 134Cs and 137Cs that emit γ- and β-rays is of primary concern, because they were released in a large amount and have a long half-life. In this study, we evaluated the heavy contamination levels of LDR effects of 134Cs and 137Cs (between 4848 and 70,200 Bq/kg) on the large Japanese field mice after the FDNPP

The study protocol followed laboratory animal care guidelines, and all procedures were conducted in accordance with the guideline of the Ethics Committee for Care and Use of Laboratory Animals for Research of Niigata University, Japan (approval number: H2611). Large Japanese field mice were captured using Sherman traps (H.B. Sherman Traps, Inc., Tallahassee, FL, USA) at three sites, Akogi, Ide, and Omaru of Namie town in the ex-evacuation zone of the FDNPP accident in November 2012, April 2013, and April 2016 (**Figure 1**). Control large Japanese mice were captured using Sherman traps in May 2012, November 2015, and April 2016 in Aomori Prefecture, and April and May 2016 in Niigata Prefecture. The ambient dose rate was measured at the sampling sites using NaI (Tl) scintillation survey meter TCS-171B (Hitachi Aloka Medical, Ltd., Tokyo, Japan) at the height of 1 m. The measurements were expressed as micrograys per

**1. Introduction**

and health risk [14].

rounding ecosystem.

accident.

from the evacuation zone [3, 7].

**2. Materials and methods**

hour at 1 m above the ground.

**2.1 Collections of large Japanese field mice**

**172**

*Sampling site of in Namie town, Niigata and Aomori. Akogi, Ide and Omaru of Namie town in the ex-evacuation zone of the FDNPP accident is shown in yellow.*

### **2.2 Measurement of radioactivity**

Radioactivities of the organ samples were determined via gamma-ray spectrometry using high-purity germanium (HPGe) detector (GEM40P4-83, Ortec Co., Oak Ridge, TN, USA) as described previously [10]. The duration of the measurement varied from 110,600 to 663,400 s, depending on the radioactivity of the sample. Absolute efficiency of the detector was determined with the standard point sources of 137Cs (10 kBq, CS402) and 152Eu (10 kBq, EU402, Japan Isotope Association, Tokyo, Japan). The samples were placed in a small space (1 mm thick and 6 mm diameter) which is the same size as the standard point sources. A nuclide was identified when its characteristic photopeak 3σ above the baseline observed in the spectrum. The activities due to decay were corrected to the sampling dates.

### **2.3 Morphological assessment of testes cells**

The testes were fixed in Bouin's solution, embedded in paraffin, and stained using haematoxylin and eosin (H&E), according to standard protocols, as described by Takino et al. [11]. Subsequently, the testes were briefly dehydrated in different concentrations of alcohol. The testes were made transparent by using toluene, and then, then they were embedded in paraffin and cut into 5 μm-thick sections before staining.

### **2.4 Electron probe X-ray microanalysis**

Qualitative analysis: An analytical method was used to investigate the composition of the sample to be analysed. From <sup>6</sup> B to 92U can be measured with a combination of analytical crystal to be used. The analysis conditions were as follows: voltage was set to 15 kV, beam current was 100 nA, beam size was minimum, sample current was 92.8 nA, and time 30 ms/point (**Figure 2**).

Elements analysis: Chemical trace analyses of caesium (Cs), sulphur (S), and nitrogen (N) in the testes were performed using a Shimadzu 1720HT electron probe micro-analyser (Shimadzu Corporation, Tokyo, Japan) equipped for X-ray spectrometry and specifically adapted for the examination of ultrathin sections. Accordingly, 3 μm of each testis section was placed on the carbon plate, and

**Figure 2.** *Result of qualitative analysis by EPMA.*

subsequently, each section was carbon coated for the electrification of samples (Biopathology Institute Co., Ltd., Oita, Japan). For the analysis, the voltage of the electron microscope was set to 15 kV, and the electron beam rate was set to 100 nA. Other parameters were beam size minimum × region (260 × 195 μm) and time (30 ms/point). The sections were viewed as secondary electron images, and chemical elemental mapping was performed. We performed EPMA analysis duplicate including test analysis.

### **3. Results and discussion**

To date, low-dose radiation effects on physiological processes including spermatogenesis remain unclear. Further studies are required to confirm these low-dose radiation effects [14].

In the present study, we examined the effects of LDR exposure associated with the FDNPP accident on the testes of large Japanese field mice from different contaminated areas in the ex-evacuation zone, at Namie town in Fukushima. The ambient dose rate at Akogi was 26.9 μGy/h in November 2012, and 15.2 μGy/h in April 2013. The dose rate at Omaru was 12.3 μGy/h in April 2016. The dose rate at Ide was 16.4 μGy/h in April 2013, and 5.3 μGy/h in April 2016 (**Table 1**).

The 134Cs and 137Cs radioactivity concentrations (Bq/kg) in large Japanese field mice organ samples were detected via gamma-ray spectrometry by using an HPGe detector (**Table 1**). The total radioactivity concentrations of 134Cs and 137Cs in large Japanese field mice organ samples from Omaru were 2510, 2750, 3860, and 37,630 Bq/kg. Those from Ide were 10,820 and 16,550 Bq/kg, and this level is highly contaminated for the large Japanese field mice in the ex-evacuation zone.

Okano et al. [17] reported that, although the concentrations of 134Cs and 137Cs in wild mice from Fukushima exceeded 4000 Bq/kg, there were no significant differences in the frequencies of apoptotic cells or morphologically abnormal sperm when compared with wild mice from the non-contaminated control area. However, Kawagoshi et al. [18] reported that the average frequencies of chromosomal aberrations in splenic lymphocytes of animals living in the heavily contaminated (approximately 3 mGy/day) area of Fukushima were higher than those of animals from the non-contaminated, slightly contaminated (approximately 0.03 mGy/day), and moderately contaminated (approximately 1 mGy/day) areas. Moreover, the

**175**

large Japanese field mice.

*Individual information for large Japanese field mice.*

Aomori (control)

Niigata (control)

**Table 1.**

Akogi were normally observed (**Figure 3D**).

and membranes (**Figure 3A**–**D**: images 6).

*Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe…*

**No. ID Site 134Cs** 

Fukushima 1 215 Akogi 11/6/2012 26.9 23.5 – – –

**dose rate (μGy/h)**

 260 19/04/2013 15.2 32.4 – – – 572 Omaru 12/4/2016 12.3 36.2 580 2880 3460 575 12/4/2016 12.3 29.2 500 2250 2750 590 12/4/2016 12.3 10.8 690 3170 3860 594 12/4/2016 12.3 28.1 460 2050 2510 595 12/4/2016 12.3 44.5 6360 31,270 37,630 257 Ide 19/04/2013 16.4 30.2 – – – 596 12/4/2016 5.3 50.1 1960 8860 10,820 597 12/4/2016 5.3 43.5 2990 13,560 16,550

11 150 Hirosaki 29/05/2012 – 37 – – –

12 2721 Kakuta 20/11/2015 – 34.2 – – –

**Body weight (g)**

**(Bq/kg)**

**Radioactive concentration of 134Cs and 137Cs**

**137Cs (Bq/kg)**

**Total (Bq/kg)**

aberration frequency in individual wild mice tended to increase with the estimated dose rates and accumulated doses. Takino et al. [11] reported that enhanced spermatogenesis occurred in large Japanese field mice living in and around the exevacuation zone of FDNPP. It remains to be elucidated whether the phenomenon, which is attributable to chronic LDR exposure, has a beneficial or adverse effect on

13 2811 18/04/2016 43.8

Morphological analysis of testes based on H&E staining showed that the stages of the seasonal reproductive cycle were classified into reproductive, non-reproductive, and transition periods (**Figure 3A**–**D**; 1). During the reproductive seasons of the large Japanese field mice from Ide, spermatogonia, primary spermatocyte, secondary spermatocyte, and sperm were observed (**Figure 3B**). Interestingly, spermatogenesis was also observed normally in the breeding season of wild mice in the heavily contaminated area of Omaru (**Figure 3C**). Moreover, it was confirmed that the regression of sperm and seminiferous tubules during the non-breeding season of the wild mice in the most heavily contaminated area of

**Figure 3A**–**D** (images 4–6) presents the phase maps obtained using the EPMA indicating micro-constituent concentrations namely, Cs, S and N. Colour imaging rapidly and effectively facilitates the overall analysis of the composite structure; specifically, decreasing levels of metal distribution are indicated from red to blue. Cs was not detected in all testes of wild mice from Ide, Akogi, and Omaru (**Figure 3A**–**D**: images 4). In the breeding samples, sulphur was detected inside seminiferous tubules, especially in sperm and was detected around the seminiferous tubules in the non-breeding seasons (**Figure 3A**–**D**: images 5). Nitrogen was detected inside both the seminiferous tubules

In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, there were no significant radiation effects on the

*DOI: http://dx.doi.org/10.5772/intechopen.84634*

**Area Large Japanese field mice Sampling date Ambient** 

*Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe… DOI: http://dx.doi.org/10.5772/intechopen.84634*


**Table 1.**

*Ionizing and Non-ionizing Radiation*

duplicate including test analysis.

*Result of qualitative analysis by EPMA.*

**3. Results and discussion**

radiation effects [14].

**Figure 2.**

subsequently, each section was carbon coated for the electrification of samples (Biopathology Institute Co., Ltd., Oita, Japan). For the analysis, the voltage of the electron microscope was set to 15 kV, and the electron beam rate was set to 100 nA. Other parameters were beam size minimum × region (260 × 195 μm) and time (30 ms/point). The sections were viewed as secondary electron images, and chemical elemental mapping was performed. We performed EPMA analysis

To date, low-dose radiation effects on physiological processes including spermatogenesis remain unclear. Further studies are required to confirm these low-dose

In the present study, we examined the effects of LDR exposure associated with the FDNPP accident on the testes of large Japanese field mice from different contaminated areas in the ex-evacuation zone, at Namie town in Fukushima. The ambient dose rate at Akogi was 26.9 μGy/h in November 2012, and 15.2 μGy/h in April 2013. The dose rate at Omaru was 12.3 μGy/h in April 2016. The dose rate at

The 134Cs and 137Cs radioactivity concentrations (Bq/kg) in large Japanese field mice organ samples were detected via gamma-ray spectrometry by using an HPGe detector (**Table 1**). The total radioactivity concentrations of 134Cs and 137Cs in large Japanese field mice organ samples from Omaru were 2510, 2750, 3860, and 37,630 Bq/kg. Those from Ide were 10,820 and 16,550 Bq/kg, and this level is highly

Okano et al. [17] reported that, although the concentrations of 134Cs and 137Cs in

wild mice from Fukushima exceeded 4000 Bq/kg, there were no significant differences in the frequencies of apoptotic cells or morphologically abnormal sperm when compared with wild mice from the non-contaminated control area. However,

Kawagoshi et al. [18] reported that the average frequencies of chromosomal aberrations in splenic lymphocytes of animals living in the heavily contaminated (approximately 3 mGy/day) area of Fukushima were higher than those of animals from the non-contaminated, slightly contaminated (approximately 0.03 mGy/day), and moderately contaminated (approximately 1 mGy/day) areas. Moreover, the

Ide was 16.4 μGy/h in April 2013, and 5.3 μGy/h in April 2016 (**Table 1**).

contaminated for the large Japanese field mice in the ex-evacuation zone.

**174**

*Individual information for large Japanese field mice.*

aberration frequency in individual wild mice tended to increase with the estimated dose rates and accumulated doses. Takino et al. [11] reported that enhanced spermatogenesis occurred in large Japanese field mice living in and around the exevacuation zone of FDNPP. It remains to be elucidated whether the phenomenon, which is attributable to chronic LDR exposure, has a beneficial or adverse effect on large Japanese field mice.

Morphological analysis of testes based on H&E staining showed that the stages of the seasonal reproductive cycle were classified into reproductive, non-reproductive, and transition periods (**Figure 3A**–**D**; 1). During the reproductive seasons of the large Japanese field mice from Ide, spermatogonia, primary spermatocyte, secondary spermatocyte, and sperm were observed (**Figure 3B**). Interestingly, spermatogenesis was also observed normally in the breeding season of wild mice in the heavily contaminated area of Omaru (**Figure 3C**). Moreover, it was confirmed that the regression of sperm and seminiferous tubules during the non-breeding season of the wild mice in the most heavily contaminated area of Akogi were normally observed (**Figure 3D**).

**Figure 3A**–**D** (images 4–6) presents the phase maps obtained using the EPMA indicating micro-constituent concentrations namely, Cs, S and N. Colour imaging rapidly and effectively facilitates the overall analysis of the composite structure; specifically, decreasing levels of metal distribution are indicated from red to blue. Cs was not detected in all testes of wild mice from Ide, Akogi, and Omaru (**Figure 3A**–**D**: images 4). In the breeding samples, sulphur was detected inside seminiferous tubules, especially in sperm and was detected around the seminiferous tubules in the non-breeding seasons (**Figure 3A**–**D**: images 5). Nitrogen was detected inside both the seminiferous tubules and membranes (**Figure 3A**–**D**: images 6).

In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, there were no significant radiation effects on the

### **Figure 3.**

*Elements analysis of large Japanese field mice testis. A. Control (ID 2811), B. Ide (ID 596), C. Akogi (ID 215), and D. Omaru (ID 595). (1) H & E staining images of testis. (2) Stereo-microscopy images. (3) Composite backscattered microscopy images. (4) Colour map images of Cs (caesium). (5) Colour map images of S (sulphur). (6) Colour map images of N (nitrogen).*

spermatogenesis and Cs in the examined large Japanese field mice testes following chronic LDR radiation exposure associated with the FDNPP accident.

### **Acknowledgements**

This work was supported by the Japan Society for the Promotion of Science, and entrusted to the Japan Atomic Energy Agency (JAEA) by the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT).

**177**

provided the original work is properly cited.

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe…*

, Kazuki Komatsu1

, Manabu Fukumoto10, Hideaki Yamashiro1

1 Graduate School of Science and Technology, Niigata University, Niigata, Japan

3 Institute of Radiation Emergency Medicine, Hirosaki University, Aomori, Japan

7 Institute for Excellence in Higher Education, Tohoku University, Sendai, Japan

10 Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan

8 Institute for Disaster Reconstruction and Regeneration Research, Tohoku

2 Graduate School of Health Sciences, Hirosaki University, Aomori, Japan

4 Faculty of Pharmacy, Hokkaido University of Science, Hokkaido, Japan

5 Graduate School of Medicine, Tohoku University, Sendai, Japan

6 Graduate School of Chemistry, Tohoku University, Sendai, Japan

9 Graduate School of Dentistry, Tohoku University, Sendai, Japan

\*Address all correspondence to: hyamashiro@agr.niigata-u.ac.jp

, Yasushi Kino6

, Kentaro Ariyoshi3

, Yoshinaka Shimizu9

, Rina Syoji1

, Yohei Fujishima<sup>2</sup>

,

,

, Akifumi Nakata4

, Hisashi Shinoda9

, Tsutomu Sekine6,7,

\*

,

*DOI: http://dx.doi.org/10.5772/intechopen.84634*

, Kanna Meguro1

, Kosuke Kasai<sup>2</sup>

, Kazuma Koarai6

, Atsushi Takahasi9

**Author details**

Takuya Ohdaira1

Valerie Swee Ting Goh<sup>2</sup>

Yusuke Urushihara5

Mitsuaki A. Yoshida3

and Tomisato Miura2,3\*

University, Sendai, Japan

and tomisato@hirosaki-u.ac.jp

Masatoshi Suzuki8

*Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe… DOI: http://dx.doi.org/10.5772/intechopen.84634*

### **Author details**

*Ionizing and Non-ionizing Radiation*

**176**

**Figure 3.**

**Acknowledgements**

*(sulphur). (6) Colour map images of N (nitrogen).*

spermatogenesis and Cs in the examined large Japanese field mice testes following

*Elements analysis of large Japanese field mice testis. A. Control (ID 2811), B. Ide (ID 596), C. Akogi (ID 215), and D. Omaru (ID 595). (1) H & E staining images of testis. (2) Stereo-microscopy images. (3) Composite backscattered microscopy images. (4) Colour map images of Cs (caesium). (5) Colour map images of S* 

This work was supported by the Japan Society for the Promotion of Science, and entrusted to the Japan Atomic Energy Agency (JAEA) by the Ministry of Education,

chronic LDR radiation exposure associated with the FDNPP accident.

Culture, Sports, Science, and Technology of Japan (MEXT).

Takuya Ohdaira1 , Kanna Meguro1 , Kazuki Komatsu1 , Rina Syoji1 , Yohei Fujishima<sup>2</sup> , Valerie Swee Ting Goh<sup>2</sup> , Kosuke Kasai<sup>2</sup> , Kentaro Ariyoshi3 , Akifumi Nakata4 , Yusuke Urushihara5 , Kazuma Koarai6 , Yasushi Kino6 , Tsutomu Sekine6,7, Masatoshi Suzuki8 , Atsushi Takahasi9 , Yoshinaka Shimizu9 , Hisashi Shinoda9 , Mitsuaki A. Yoshida3 , Manabu Fukumoto10, Hideaki Yamashiro1 \* and Tomisato Miura2,3\*

1 Graduate School of Science and Technology, Niigata University, Niigata, Japan

2 Graduate School of Health Sciences, Hirosaki University, Aomori, Japan

3 Institute of Radiation Emergency Medicine, Hirosaki University, Aomori, Japan

4 Faculty of Pharmacy, Hokkaido University of Science, Hokkaido, Japan

5 Graduate School of Medicine, Tohoku University, Sendai, Japan

6 Graduate School of Chemistry, Tohoku University, Sendai, Japan

7 Institute for Excellence in Higher Education, Tohoku University, Sendai, Japan

8 Institute for Disaster Reconstruction and Regeneration Research, Tohoku University, Sendai, Japan

9 Graduate School of Dentistry, Tohoku University, Sendai, Japan

10 Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan

\*Address all correspondence to: hyamashiro@agr.niigata-u.ac.jp and tomisato@hirosaki-u.ac.jp

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[2] Isogai E, Kino Y, Abe Y, Yamashiro H, Shinoda H, Fukuda T, et al. Distribution of radioactive cesium in ostrich (*Struthio Camelus*) after the Fukushima Daiichi nuclear power plant accident. Radiation Emergency Medicine. 2013;**2**:68-71

[3] Yamashiro H, Abe Y, Fukuda T, Kino Y, Kawaguchi I, Kuwahara Y, et al. Effects of radioactive caesium on bull testes after the Fukushima nuclear plant accident. Scientific Reports. 2013;**3**:2850

[4] Hosoda M, Tokonami S, Tazoe H, Sorimachi A, Monzen S, Osanai M, et al. Activity concentrations of environmental samples collected in Fukushima Prefecture immediately after the Fukushima nuclear accident. Scientific Reports. 2013;**3**:2283

[5] Fukuda T, Kino Y, Abe Y, Yamashiro H, Kobayashi J, Shimizu Y, et al. Cesium radioactivity in peripheral blood is linearly correlated to that in skeletal muscle: Analyses of cattle within the evacuation zone of the Fukushima Daiichi nuclear power plant. Animal Science Journal. 2015;**86**:120-124

[6] Takahashi S, Inoue K, Urushihara Y, Hayashi G, Kino Y, Sekine T, et al. A comprehensive dose evaluation project concerning animals affected by the Fukushima Daiichi nuclear power plant accident: Its setup and progress. Journal of Radiation Research. 2015;**56**(S1):i36-i41

[7] Yamashiro H, Abe Y, Hayashi G, Urushihara Y, Kuwahara Y, Suzuki M, et al. Electron probe X-ray microanalysis of boar and inobuta testes after the Fukushima accident. Journal of Radiation Research. 2015;**56**(S1):i42-i47

[8] Fukuda T, Hiji M, Kino Y, Abe Y, Yamashiro H, Kobayashi J, et al. Software development for estimating the cesium radioactivity in skeletal muscle from that in blood of cattle. Animal Science Journal. 2016;**87**:842-847

[9] Koarai K, Kino Y, Takahashi A, Suzuki T, Shimizu Y, Chiba M, et al. 90Sr in teeth of cattle abandoned in evacuation zone: Record of pollution from the Fukushima-Daiichi nuclear power plant accident. Scientific Reports. 2016;**6**:24077

[10] Urushihara Y, Kawasumi K, Endo S, Tanaka K, Hirakawa Y, Hayashi G, et al. Analysis of plasma protein concentrations and enzyme activities in cattle within the ex-evacuation zone of the Fukushima Daiichi nuclear plant accident. PLoS One. 2016;**11**:e0155069

[11] Takino S, Yamashiro H, Sugano Y, Fujishima Y, Nakata A, Kasai K, et al. Analysis of the effect of chronic and low-dose radiation exposure on spermatogenic cells of male large Japanese field mice (*Apodemus speciosus*) after the Fukushima Daiichi nuclear power plant accident. Radiation Research. 2017;**187**:161-168

[12] Koarai K, Kino Y, Takahashi A, Suzuki T, Shimizu Y, Chiba M, et al. 90Sr specific activity of teeth of abandoned cattle after the Fukushima accident— Teeth as an indicator of environmental pollution. Journal of Environmental Radioactivity. 2018;**183**:1-6

[13] Ariyoshi K, Miura T, Kasai K, Akifumi N, Fujishima Y, Yoshida MA. Radiation-induced bystander effect in large Japanese field mouse (*Apodemus speciosus*) embryonic cells. Radiation and Environmental Biophysics. 2018;**57**:223-231

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[15] Suzuki H, Yasuda SP, Sakaizumi M, Wakana S, Motokawa M, Tsuchiya K. Differential geographic patterns of mitochondrial DNA variation in two sympatric species of Japanese wood mice, *Apodemus speciosus* and *A. argenteus*. Genes & Genetic Systems.

[16] Pogorelov AG, Budantsev AY, Pogorelova VN. Quantitative electron probe microanalysis of

acetylcholinesterase activity in rat brain sections. Journal of Histochemistry and Cytochemistry. 1993;**41**:1795-1800

[17] Okano T, Ishiniwa H, Onuma M, Shindo J, Yokohata Y, Tamaoki M. Effects of environmental radiation on testes and spermatogenesis in wild large Japanese field mice (*Apodemus speciosus*) from Fukushima. Scientific Reports.

[18] Kawagoshi T, Shiomi N, Takahashi H, Watanabe Y, Fuma S, Doi K, et al. Chromosomal aberrations in large Japanese field mice (*Apodemus speciosus*) captured near Fukushima Dai-ichi nuclear power plant.

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[14] Fukunaga H, Butterworth KT, Yokoya A, Ogawa T, Prise KM. Lowdose radiation-induced risk in

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[14] Fukunaga H, Butterworth KT, Yokoya A, Ogawa T, Prise KM. Lowdose radiation-induced risk in spermatogenesis. International Journal of Radiation Biology. 2017;**93**:1291-1298

[15] Suzuki H, Yasuda SP, Sakaizumi M, Wakana S, Motokawa M, Tsuchiya K. Differential geographic patterns of mitochondrial DNA variation in two sympatric species of Japanese wood mice, *Apodemus speciosus* and *A. argenteus*. Genes & Genetic Systems. 2004;**79**:165-176

[16] Pogorelov AG, Budantsev AY, Pogorelova VN. Quantitative electron probe microanalysis of acetylcholinesterase activity in rat brain sections. Journal of Histochemistry and Cytochemistry. 1993;**41**:1795-1800

[17] Okano T, Ishiniwa H, Onuma M, Shindo J, Yokohata Y, Tamaoki M. Effects of environmental radiation on testes and spermatogenesis in wild large Japanese field mice (*Apodemus speciosus*) from Fukushima. Scientific Reports. 2016;**6**:23601

[18] Kawagoshi T, Shiomi N, Takahashi H, Watanabe Y, Fuma S, Doi K, et al. Chromosomal aberrations in large Japanese field mice (*Apodemus speciosus*) captured near Fukushima Dai-ichi nuclear power plant. Environmental Science & Technology. 2017;**51**:4632-4641

**178**

2015;**56**(S1):i36-i41

*Ionizing and Non-ionizing Radiation*

H, Kuwahara Y, Nihei H, et al.

in the abandoned cattle in the evacuation zone of the Fukushima Daiichi nuclear power plant. PLoS One.

[1] Fukuda T, Kino Y, Abe Y, Yamashiro

after the Fukushima accident. Journal of Radiation Research. 2015;**56**(S1):i42-i47

Software development for estimating the cesium radioactivity in skeletal muscle from that in blood of cattle. Animal Science Journal. 2016;**87**:842-847

[9] Koarai K, Kino Y, Takahashi A, Suzuki T, Shimizu Y, Chiba M, et al. 90Sr in teeth of cattle abandoned in evacuation zone: Record of pollution from the Fukushima-Daiichi nuclear power plant accident. Scientific Reports. 2016;**6**:24077

[10] Urushihara Y, Kawasumi K, Endo S, Tanaka K, Hirakawa Y, Hayashi G, et al. Analysis of plasma protein concentrations and enzyme activities in cattle within the ex-evacuation zone of the Fukushima Daiichi nuclear plant accident. PLoS One.

[11] Takino S, Yamashiro H, Sugano Y, Fujishima Y, Nakata A, Kasai K, et al. Analysis of the effect of chronic and low-dose radiation exposure on spermatogenic cells of male large

Japanese field mice (*Apodemus speciosus*) after the Fukushima Daiichi nuclear power plant accident. Radiation Research. 2017;**187**:161-168

[12] Koarai K, Kino Y, Takahashi A, Suzuki T, Shimizu Y, Chiba M, et al. 90Sr specific activity of teeth of abandoned cattle after the Fukushima accident— Teeth as an indicator of environmental pollution. Journal of Environmental

Radioactivity. 2018;**183**:1-6

2018;**57**:223-231

[13] Ariyoshi K, Miura T, Kasai K, Akifumi N, Fujishima Y, Yoshida MA. Radiation-induced bystander effect in large Japanese field mouse (*Apodemus speciosus*) embryonic cells. Radiation and Environmental Biophysics.

2016;**11**:e0155069

[8] Fukuda T, Hiji M, Kino Y, Abe Y, Yamashiro H, Kobayashi J, et al.

Distribution of artificial radionuclides

[2] Isogai E, Kino Y, Abe Y, Yamashiro H, Shinoda H, Fukuda T, et al. Distribution of radioactive cesium in ostrich (*Struthio Camelus*) after the Fukushima Daiichi nuclear power plant accident. Radiation Emergency Medicine. 2013;**2**:68-71

[3] Yamashiro H, Abe Y, Fukuda T, Kino Y, Kawaguchi I, Kuwahara Y, et al. Effects of radioactive caesium on bull testes after the Fukushima nuclear plant accident. Scientific Reports. 2013;**3**:2850

[4] Hosoda M, Tokonami S, Tazoe H, Sorimachi A, Monzen S, Osanai M, et al. Activity concentrations of environmental samples collected in Fukushima Prefecture immediately after the Fukushima nuclear accident.

Scientific Reports. 2013;**3**:2283

[5] Fukuda T, Kino Y, Abe Y, Yamashiro H, Kobayashi J, Shimizu Y, et al. Cesium radioactivity in peripheral blood is linearly correlated to that in skeletal muscle: Analyses of cattle within the evacuation zone of the Fukushima Daiichi nuclear power plant. Animal Science Journal. 2015;**86**:120-124

[6] Takahashi S, Inoue K, Urushihara Y, Hayashi G, Kino Y, Sekine T, et al. A comprehensive dose evaluation project concerning animals affected by the Fukushima Daiichi nuclear power plant accident: Its setup and progress. Journal of Radiation Research.

[7] Yamashiro H, Abe Y, Hayashi G, Urushihara Y, Kuwahara Y, Suzuki M,

microanalysis of boar and inobuta testes

et al. Electron probe X-ray

**References**

2013;**8**, e54312

Chapter 10

Abstract

Environmental Radiation: Natural

People are continuously exposed to ionizing radiation from many sources, including natural radioactive substances that are produced in the atmosphere and on Earth, in addition to radionuclides manufactured for various applications. Exposures vary among different places depending on many parameters. There are regions with considerably high natural background radiation while most places classified as low to medium levels. This noticeable interest pronounced worldwide is radioactivity monitoring and wide surveys by many countries. This is useful for the assessment of public as well as creating baseline if changes in the levels due to activities and practices take place. Good management of protecting the environment is to establish baseline data of high quality with efficient measurements. Natural radioactivity monitoring in view of radiation and environmental protection is presented in this chapter. It will shed the light on rapid methods describing the measurement of radionuclides and assessment of exposure to human. It presents a summary of methods of radiation dose calculations that individual may be exposed with some numerical examples. The chapter also presents methods for predicting the spatial distribution of radiological quantities using geographical information system. Environmental measurements may be costly and time-consuming practices;

Radioactivity Monitoring

hence, thoughts to reduce time force itself in this chapter.

ambient dose, absorbed dose, GIS, geostatistics

1. Introduction

181

Keywords: environmental radioactivity, monitoring, gamma spectrometry,

Our planet, the earth, is a wonderful place and has been suitable to live on its surface for thousands of years; it obliges us to preserve and nurture it. As investment volumes continue to grow in the globalized economy, environmental shadows are intersecting more and more on this planet. The concept of sustainable development, which generally means meeting the needs of the present without assaulting the rights of future generations, is addressed and implemented by many countries to manage the environment in an equal manner. However, there are some nations that achieve growth for their economies without regard to the adverse effects on the open environment. Nuclear and related applications became available everywhere to solve many problems of humanity. These applications, if not managed correctly, may lead to adverse effects of contaminating our environment by adding radioactive materials to already existing radioactivity of natural origin. So that our future generations and we will not be the victims of the various contaminations with

Isam Salih Mohamed Musa

### Chapter 10

## Environmental Radiation: Natural Radioactivity Monitoring

Isam Salih Mohamed Musa

### Abstract

People are continuously exposed to ionizing radiation from many sources, including natural radioactive substances that are produced in the atmosphere and on Earth, in addition to radionuclides manufactured for various applications. Exposures vary among different places depending on many parameters. There are regions with considerably high natural background radiation while most places classified as low to medium levels. This noticeable interest pronounced worldwide is radioactivity monitoring and wide surveys by many countries. This is useful for the assessment of public as well as creating baseline if changes in the levels due to activities and practices take place. Good management of protecting the environment is to establish baseline data of high quality with efficient measurements. Natural radioactivity monitoring in view of radiation and environmental protection is presented in this chapter. It will shed the light on rapid methods describing the measurement of radionuclides and assessment of exposure to human. It presents a summary of methods of radiation dose calculations that individual may be exposed with some numerical examples. The chapter also presents methods for predicting the spatial distribution of radiological quantities using geographical information system. Environmental measurements may be costly and time-consuming practices; hence, thoughts to reduce time force itself in this chapter.

Keywords: environmental radioactivity, monitoring, gamma spectrometry, ambient dose, absorbed dose, GIS, geostatistics

### 1. Introduction

Our planet, the earth, is a wonderful place and has been suitable to live on its surface for thousands of years; it obliges us to preserve and nurture it. As investment volumes continue to grow in the globalized economy, environmental shadows are intersecting more and more on this planet. The concept of sustainable development, which generally means meeting the needs of the present without assaulting the rights of future generations, is addressed and implemented by many countries to manage the environment in an equal manner. However, there are some nations that achieve growth for their economies without regard to the adverse effects on the open environment. Nuclear and related applications became available everywhere to solve many problems of humanity. These applications, if not managed correctly, may lead to adverse effects of contaminating our environment by adding radioactive materials to already existing radioactivity of natural origin. So that our future generations and we will not be the victims of the various contaminations with

hazards, we must preserve our environment. Many models arise when large companies offer their products without paying attention to long-term effects on human health or environmental stability. Some states allow the export of banned products or remainders inside the country because they are not safe in domestic use. In that regard, there are some talk about agreements to bury dangerous waste (e.g., radioactive waste in deserts). We recognize this by developing appropriate solutions and standards to perform the required tasks. These procedures often require the availability of accurate information and must be much easier to facilitate making decisions. The environmental radiation monitoring, for example, requires a variety of measurements, so it needs development of equipment capable of performing fast and accurate measurements on demand in addition to training of people that deals with radioactive materials.

for evaluating isotopes in the environment in efficient manner. Depending on the isotope, the analytical technique is selected (alpha, beta, or gamma emitter). Gamma radiation emitted from naturally occurring radioisotopes, also called terrestrial background radiation, represents the main external source of irradiation of the human body. Natural environmental radioactivity and the associated external exposure due to gamma radiation depend primarily on the geological and geographical conditions, as reported at different levels in the soils of different regions around the world [11–13]. The specific levels of terrestrial environmental radiation are related to the geological composition of each lithologically separated area and to the content in thorium (Th), uranium (U), and potassium (K) of the rock from

This topic received some interests by many researchers in the field. Regardless of

the general situation of safety and exposures, there are a number of conceptual issues, which remain open. That may include better revision of the protection concepts to cope with conditions of long-term chronic exposure resulting from natural sources. Developing real-world methodologies for the assessment and regulation of situations where there is a potential of exposure and addressing long-term safety aspects of radioactive waste of natural origin deem necessary. For decades, several studies have been conducted on the behavior of radionuclides in the environment and their transfer to humans through ecological and food chains. Most research focused on the contamination of the food chain release to the environment and development of mathematical models to describe environmental transport and assessment of general exposure. Continuing basic biological research is of particular importance to progress in protecting human, animal, and the environment from the hazards of radiation, so it should be strongly supported. However, it is also important to allow epidemiology, especially studies of low-dose populations, and to improve understanding of environmental phenomena as they relate to radiation

Many practices nowadays may increase the risk of surface contamination by radioactivity which needs control, such as oil exploration leading to NORMs, phosphate fertilizers, and illegal disposal of radioactive wastes in remote areas. Environmental monitoring can afford valuable means for understanding the distribution of natural worries of the ecological system. It is therefore importantly needed to increase our knowledge of the system by better means and offer adequate information to regulators, decision-makers, and the public. Authorities and investigators make baseline data such as risk maps to identify areas with low or high concentra-

Environmental sample includes anything on the earth (soil, rocks, plants, water, sediments, air, etc.). It is important that samples taken from any place have to be representative to that place and care necessity be taken not to cross-contaminate samples. These precautions include also storing samples in a safe place to prevent conditions that could change the properties of the sample. Samples shall be kept sealed during long-term storing or transport. Before sampling a protocol, sampling strategy has to be set and all records of field sampling are written in a certain logbook. Simple logbook contains basic information of samples and sampling (date/ time, coordinates, climate conditions, dose rate readings, etc.) It may contain additional information such as where and how samples are taken. As an example, soil

which the soils originate in each area.

2.1 Radiation protection from natural sources

Environmental Radiation: Natural Radioactivity Monitoring

DOI: http://dx.doi.org/10.5772/intechopen.85115

protection, so as not to throw our hands at risk.

tions of certain radioactive and nonradioactive elements.

2.2 Environmental samples and sampling

183

### 2. Natural radioactivity

In nature, there are important components that cast a shadow over the existing development of humankind such as uranium, which contributed greatly to the generation of electricity around the world. This element, in addition to other natural radionuclides, believed to be originated during the supernova explosion millions of years ago and/or alien to the earth where it was formed in the fusion of neutron stars, eventually makes its way into the earth crust. Natural radioactivity is a term used to describe the levels of naturally occurring radionuclides in different environmental compartments, originated either from cosmic (e.g., 14C and <sup>3</sup> H) or terrestrial radiation. In addition to radioactive potassium (40K), the terrestrial radionuclides include those contained in four known decays series, namely, uranium, thorium, actinium, and neptunium, which start with 238U, 232Th, 235U, and 237Np, respectively. They comprise 18, 11, 16, and 12 radionuclides, respectively. The most abundant in significant levels in our environment are those from 238U and 232Th series. It is believed that in the history of the earth, the crust was enriched in uranium in the beginning; then, the rise of oxygen had oxidized uranium leading to the transfer of huge amount to the oceans and by some natural processes back to the mantle [1, 2]. The processes involved led to spatial distribution of uranium and its decay products. No matter how these theories and assumptions are exact, they give a picture of the approach we can only prove their validity by experiments.

Natural environmental radioactivity arises primarily not only from uranium, as mentioned above, but includes also other nuclides, such as thorium series and potassium, which occur at trace levels in all formations. These radionuclides are believed to be formed by the process of nucleosynthesis in stars and are characterized by half-lives that are comparable to the age of the earth.

It has been recognized that there are some places with large inhabitants that encompass high levels of background radiation in environmental compartments. Great interest given worldwide for the study of naturally occurring radionuclides has led to the performance of broad investigations in many countries [3–10]. Investigators attempted to correlate the distributions of natural radionuclides with some settings such as geology, soil characteristics, etc. Such surveys can be useful for both the assessment of dose rates and the exploit of epidemiological studies, as well as to keep reference-data histories and to determine possible changes in the environmental radioactivity due to nuclear, industrial, or any other practices. What matters to us is to deal with the current reality of taking advantage of natural resources without disruption and tampering with our environment. The accurate determination of isotopes in environmental media presents a significant contest. Thanks to the technology that offered today many nuclear and related techniques

Environmental Radiation: Natural Radioactivity Monitoring DOI: http://dx.doi.org/10.5772/intechopen.85115

hazards, we must preserve our environment. Many models arise when large companies offer their products without paying attention to long-term effects on human health or environmental stability. Some states allow the export of banned products or remainders inside the country because they are not safe in domestic use. In that regard, there are some talk about agreements to bury dangerous waste (e.g., radioactive waste in deserts). We recognize this by developing appropriate solutions and standards to perform the required tasks. These procedures often require the availability of accurate information and must be much easier to facilitate making decisions. The environmental radiation monitoring, for example, requires a variety of measurements, so it needs development of equipment capable of performing fast and accurate measurements on demand in addition to training of people that deals

In nature, there are important components that cast a shadow over the existing development of humankind such as uranium, which contributed greatly to the generation of electricity around the world. This element, in addition to other natural radionuclides, believed to be originated during the supernova explosion millions of years ago and/or alien to the earth where it was formed in the fusion of neutron stars, eventually makes its way into the earth crust. Natural radioactivity is a term used to describe the levels of naturally occurring radionuclides in different envi-

H) or ter-

ronmental compartments, originated either from cosmic (e.g., 14C and <sup>3</sup>

restrial radiation. In addition to radioactive potassium (40K), the terrestrial radionuclides include those contained in four known decays series, namely, uranium, thorium, actinium, and neptunium, which start with 238U, 232Th, 235U, and 237Np, respectively. They comprise 18, 11, 16, and 12 radionuclides, respectively. The most abundant in significant levels in our environment are those from 238U and 232Th series. It is believed that in the history of the earth, the crust was enriched in uranium in the beginning; then, the rise of oxygen had oxidized uranium leading to the transfer of huge amount to the oceans and by some natural processes back to the mantle [1, 2]. The processes involved led to spatial distribution of uranium and its decay products. No matter how these theories and assumptions are exact, they give

a picture of the approach we can only prove their validity by experiments.

ized by half-lives that are comparable to the age of the earth.

mentioned above, but includes also other nuclides, such as thorium series and potassium, which occur at trace levels in all formations. These radionuclides are believed to be formed by the process of nucleosynthesis in stars and are character-

Natural environmental radioactivity arises primarily not only from uranium, as

It has been recognized that there are some places with large inhabitants that encompass high levels of background radiation in environmental compartments. Great interest given worldwide for the study of naturally occurring radionuclides has led to the performance of broad investigations in many countries [3–10]. Investigators attempted to correlate the distributions of natural radionuclides with some settings such as geology, soil characteristics, etc. Such surveys can be useful for both the assessment of dose rates and the exploit of epidemiological studies, as well as to keep reference-data histories and to determine possible changes in the environmental radioactivity due to nuclear, industrial, or any other practices. What matters to us is to deal with the current reality of taking advantage of natural resources without disruption and tampering with our environment. The accurate determination of isotopes in environmental media presents a significant contest. Thanks to the technology that offered today many nuclear and related techniques

with radioactive materials.

Ionizing and Non-ionizing Radiation

2. Natural radioactivity

182

for evaluating isotopes in the environment in efficient manner. Depending on the isotope, the analytical technique is selected (alpha, beta, or gamma emitter).

Gamma radiation emitted from naturally occurring radioisotopes, also called terrestrial background radiation, represents the main external source of irradiation of the human body. Natural environmental radioactivity and the associated external exposure due to gamma radiation depend primarily on the geological and geographical conditions, as reported at different levels in the soils of different regions around the world [11–13]. The specific levels of terrestrial environmental radiation are related to the geological composition of each lithologically separated area and to the content in thorium (Th), uranium (U), and potassium (K) of the rock from which the soils originate in each area.

### 2.1 Radiation protection from natural sources

This topic received some interests by many researchers in the field. Regardless of the general situation of safety and exposures, there are a number of conceptual issues, which remain open. That may include better revision of the protection concepts to cope with conditions of long-term chronic exposure resulting from natural sources. Developing real-world methodologies for the assessment and regulation of situations where there is a potential of exposure and addressing long-term safety aspects of radioactive waste of natural origin deem necessary. For decades, several studies have been conducted on the behavior of radionuclides in the environment and their transfer to humans through ecological and food chains. Most research focused on the contamination of the food chain release to the environment and development of mathematical models to describe environmental transport and assessment of general exposure. Continuing basic biological research is of particular importance to progress in protecting human, animal, and the environment from the hazards of radiation, so it should be strongly supported. However, it is also important to allow epidemiology, especially studies of low-dose populations, and to improve understanding of environmental phenomena as they relate to radiation protection, so as not to throw our hands at risk.

Many practices nowadays may increase the risk of surface contamination by radioactivity which needs control, such as oil exploration leading to NORMs, phosphate fertilizers, and illegal disposal of radioactive wastes in remote areas. Environmental monitoring can afford valuable means for understanding the distribution of natural worries of the ecological system. It is therefore importantly needed to increase our knowledge of the system by better means and offer adequate information to regulators, decision-makers, and the public. Authorities and investigators make baseline data such as risk maps to identify areas with low or high concentrations of certain radioactive and nonradioactive elements.

### 2.2 Environmental samples and sampling

Environmental sample includes anything on the earth (soil, rocks, plants, water, sediments, air, etc.). It is important that samples taken from any place have to be representative to that place and care necessity be taken not to cross-contaminate samples. These precautions include also storing samples in a safe place to prevent conditions that could change the properties of the sample. Samples shall be kept sealed during long-term storing or transport. Before sampling a protocol, sampling strategy has to be set and all records of field sampling are written in a certain logbook. Simple logbook contains basic information of samples and sampling (date/ time, coordinates, climate conditions, dose rate readings, etc.) It may contain additional information such as where and how samples are taken. As an example, soil

samples can be taken using auger with depths up to 20 cm (after removing the top 2–3 cm). Locations of samples have to be pre-defined on approximate map, and from each location, a set of triplicate samples (as shown in Figure 1) could be taken. Samples are then prepared for measurements in standard procedures (drying, grinding, sieving, etc.). Details about sample preparation are described elsewhere such as the IAEA Technical Report Series No. 295 [14].

2.4 Gamma ray laboratory

spectrum taken for environmental sample.

Environmental Radiation: Natural Radioactivity Monitoring

DOI: http://dx.doi.org/10.5772/intechopen.85115

2.5 In situ ambient dose measurement

A typical gamma measurement spectrum obtained using HPGe system.

accurate, and precise.

Figure 2.

185

Gamma spectrometry is a system that is equipped with various types of detectors (HPGe, BEGe, LEGe, NaI, etc.), which characterized its specifications for radioactivity measurements. Germanium detectors are powerful systems used to measure the radioactivity in environmental samples. They have many advantages compared to other techniques as, for example, they distinguish many radionuclides in one single measurement without destruction or chemical modification of the sample. Simultaneous identification of many radionuclides with specific gamma energy and high-energy resolution of the germanium detectors allows measurements of complex combinations of gamma emitters. Figure 2 shows typical gamma

It is important to know what counting statistics is used to optimize counting times in view of the influence of background. Depending on detector characteristics, the minimum detectable activity (MDA) at specific energy E is an important parameter to be calculated for field measurements; this may be given using Eq. (1):

where R(E), B(E), and ε(E) are resolution of the detector (keV), background

Measurements are generally carried out using various radiation survey meters that can have different detection abilities. The choice of field measuring devices usually depends on how sensitive these devices are to different energies of different concentrations of radionuclides in the environment. Quality control has to be conducted by researcher and investigators to make sure these devices are reliable,

An example of the reliability of field, compared to the laboratory measurements, will be given here. In a recent survey, a portable dose rate meter device (Radiogem2000 with probe [16]) was set to measure dose rates, DF (μSv/h) at 1 meter above the ground while at the same time taking soil samples from the same

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi R Eð ÞB Eð Þ <sup>p</sup>

<sup>ε</sup>ð Þ <sup>E</sup> , (1)

MDA ¼

(counts/keV), and total efficiency at the specific energy E, respectively.

### 2.3 Gamma radiation monitoring

Among other types of radiation, gamma rays are the most penetrating radiation that are emitted from natural and manufactured sources. This property made gamma rays easy to detect and measure. Measurements can be made in two manners: total measurements that record gamma rays emitted at different energies from various sources. These modes are generally used to evaluate the gross levels of the gamma radiation in fields and to detect the presence of abnormalities in the environment. Laboratory analyses, on the other hand, measure both the intensity and energy of radiation, which enables identification of the source of the radiation.

Gamma radiation monitoring is applied in several fields of science including geological, geochemical, and mineral exploration, related epidemiological studies, and environmental science. It allows the interpretation of regional features over large areas. The monitoring is useful to estimate and assess the terrestrial radiation dose to the human population and to recognize regions of probable natural radiation hazard. Radioactive potassium and the uranium and thorium decay series are relatively abundant in the natural environment. They produce gamma rays of sufficient energies and intensities to be detected by a simple gamma ray spectrometry. Average crustal abundances of these elements quoted in the literature are in the range 2–2.5%, 2–3 ppm, and 8–12 ppm for potassium, uranium, and thorium, respectively [12].

Regional monitoring provides a base against which contamination from artificial sources be estimated. For example, regular measurements are conducted around nuclear facilities such as power plants, hospitals, and mining, industrial, and even radiowaste sites to provide a baseline against which any unintentional release of radioactive material can be detected. The gamma ray techniques have been fruitfully applied to mapping the fallout from nuclear accidents [15].

Figure 1. Part of soil sampling area where triplicate samples are found from each location in the area.

### 2.4 Gamma ray laboratory

samples can be taken using auger with depths up to 20 cm (after removing the top 2–3 cm). Locations of samples have to be pre-defined on approximate map, and from each location, a set of triplicate samples (as shown in Figure 1) could be taken. Samples are then prepared for measurements in standard procedures (drying, grinding, sieving, etc.). Details about sample preparation are described elsewhere

Among other types of radiation, gamma rays are the most penetrating radiation

that are emitted from natural and manufactured sources. This property made gamma rays easy to detect and measure. Measurements can be made in two manners: total measurements that record gamma rays emitted at different energies from various sources. These modes are generally used to evaluate the gross levels of the gamma radiation in fields and to detect the presence of abnormalities in the environment. Laboratory analyses, on the other hand, measure both the intensity and energy of radiation, which enables identification of the source of the radiation. Gamma radiation monitoring is applied in several fields of science including geological, geochemical, and mineral exploration, related epidemiological studies, and environmental science. It allows the interpretation of regional features over large areas. The monitoring is useful to estimate and assess the terrestrial radiation dose to the human population and to recognize regions of probable natural radiation hazard. Radioactive potassium and the uranium and thorium decay series are relatively abundant in the natural environment. They produce gamma rays of sufficient energies and intensities to be detected by a simple gamma ray spectrometry. Average crustal abundances of these elements quoted in the literature are in the range 2–2.5%, 2–3 ppm, and 8–12 ppm for potassium, uranium, and thorium, respectively [12]. Regional monitoring provides a base against which contamination from artificial sources be estimated. For example, regular measurements are conducted around nuclear facilities such as power plants, hospitals, and mining, industrial, and even radiowaste sites to provide a baseline against which any unintentional release of radioactive material can be detected. The gamma ray techniques have been fruit-

fully applied to mapping the fallout from nuclear accidents [15].

Part of soil sampling area where triplicate samples are found from each location in the area.

such as the IAEA Technical Report Series No. 295 [14].

2.3 Gamma radiation monitoring

Ionizing and Non-ionizing Radiation

Figure 1.

184

Gamma spectrometry is a system that is equipped with various types of detectors (HPGe, BEGe, LEGe, NaI, etc.), which characterized its specifications for radioactivity measurements. Germanium detectors are powerful systems used to measure the radioactivity in environmental samples. They have many advantages compared to other techniques as, for example, they distinguish many radionuclides in one single measurement without destruction or chemical modification of the sample. Simultaneous identification of many radionuclides with specific gamma energy and high-energy resolution of the germanium detectors allows measurements of complex combinations of gamma emitters. Figure 2 shows typical gamma spectrum taken for environmental sample.

It is important to know what counting statistics is used to optimize counting times in view of the influence of background. Depending on detector characteristics, the minimum detectable activity (MDA) at specific energy E is an important parameter to be calculated for field measurements; this may be given using Eq. (1):

$$\text{MDA} = \frac{\sqrt{R(E)B(E)}}{\varepsilon(E)},\tag{1}$$

where R(E), B(E), and ε(E) are resolution of the detector (keV), background (counts/keV), and total efficiency at the specific energy E, respectively.

### 2.5 In situ ambient dose measurement

Measurements are generally carried out using various radiation survey meters that can have different detection abilities. The choice of field measuring devices usually depends on how sensitive these devices are to different energies of different concentrations of radionuclides in the environment. Quality control has to be conducted by researcher and investigators to make sure these devices are reliable, accurate, and precise.

An example of the reliability of field, compared to the laboratory measurements, will be given here. In a recent survey, a portable dose rate meter device (Radiogem2000 with probe [16]) was set to measure dose rates, DF (μSv/h) at 1 meter above the ground while at the same time taking soil samples from the same

A typical gamma measurement spectrum obtained using HPGe system.

locations for laboratory analyses of 238U, 232Th, and 40K in the collected samples. Ambient dose rates (DC) are calculated from the measurements using Eq. (2):

$$\mathbf{D(nGy/h)} = \mathbf{0.4 \, 61A\_U + 0.623A\_{Th} + 0.0414A\_K} \tag{2}$$

2.7 Geographical information system (GIS) for radioactivity monitoring

Environmental Radiation: Natural Radioactivity Monitoring

DOI: http://dx.doi.org/10.5772/intechopen.85115

designed to acquire, store, manipulate, display, and report geographically

kriging.

2.7.1 Inverse distance weighting (IDW)

predicted and actual values.

semivariogram γ(h) function is given by Eq. (3):

<sup>γ</sup>ð Þ¼ <sup>h</sup> <sup>1</sup>

primary and secondary variables are correlated [17, 18].

<sup>2</sup>N hð Þ <sup>∑</sup> N i¼1

2.7.2 Kriging method

187

In a simple form, GIS is defined as a set of computer hardware and software

referenced information for a particular purpose in space. The space is presented by geographic coordinate systems. Therefore, GIS defines the relationships between various database information and geographical locations within the location system. Together with geostatistical tools, GIS is useful to interpolate scatter data by converting measured points into continuous surfaces. There are several methods available, the choice of which depends on the data itself. Among these methods it is worth to mention two methods, namely, inverse distance weighting (IDW) and

In this interpolator, the data points are weighted during process so that the impact of points relative to each other is a function of inverse distance. Weighting is calculated to data via the use of a weighting power and the radius object. Larger power means that the adjacent points have the larger influence. Searching radius could be fixed or variable (with typical values of power around two). This flexibility allows controlling the interpolation, which may depend on the number of samples and how they are spatially distributed. One of the drawbacks using this method is that maxima and minima are always among data points since the inverse distance weighted interpolation is a smoothing technique by definition. On the other hand, it is a powerful interpolation technique which leads to reasonable predictions with no problem with results exceeding the range of meaningful values. Simple or advance GIS software could be employed to interpolate and validate the results. Validations are normally expressed as root mean squares error in the correlation between the

This is an advance method that makes a surface from scattered points. It is sometimes called weighted moving averaging method because it is derived from regionalized variable theory. It assumes that the variation of a parameter is statistically correlated all over the area. Kriging derives weights from semivariogram functions that depict the degree of spatial correlation between data points as a function of distance and directions between points. The semivariogram adjusts the way kriging weights are allocated to each data point during interpolation. The

q

where xi + h and xi are sampling position separated by a vector h, Z(xi) is a random variable at fixed position xi, and N(h) is the number of data pairs separated by a vector h. Ordinary kriging is a type of kriging that uses the sampled main variable to estimate values at unsampled locations. Cokriging, on the other hand, allows secondary variables to be incorporated in the model assuming that both

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ½ � Z xð Þ� <sup>i</sup> <sup>þ</sup> <sup>h</sup> Z xi ð Þ <sup>2</sup>

(3)

where AU, ATh, and AK are the activity concentrations (Bq/kg) of 238U, 232Th, and 40K, respectively [11].

As shown in Figure 3, a very good linear relationship between field and laboratory measurements (calculated absorbed dose) was clearly perceived for about 100 data points with moderate dose rates (DC ≈ 0.7DF, R2 = 0.97). Of course, this result could be validated with more measurements. The most important outcome of that investigation is that at normal situations where the absorbed dose is up to 300 nGy/ h, the field measurements have good agreement with laboratory measurements. It is therefore safe to rely on the portable devices for routine monitoring. The implication of that is that many measurements could be performed in a field mission (as the measurement takes only few minutes long). If levels are high, then sampling and laboratory measurements force itself.

### 2.6 Real-time radiation monitoring in the environment

The level of background radiation can be used as a consideration in remedial actions if contamination occurs. If measured constantly, it gives info about the trends with time and impact of man-made activities. Hence, it is important to carry out systematic investigations on ambient gamma dose throughout to establish a baseline database for future control assessment where it acts as early warning system.

The early warning system is composed of detectors installed at different locations and connected to central server over available communication system. Any type of detector or survey meters could be installed and used to fulfill the requirements. The advantage of this system is that the authority can create a national radiation map, showing environmental radiation levels (gross count of the radioactivity) throughout certain area updated in real time. It allows the citizen (or anyone) to see what radiation levels are within that specific area at any instance.

Figure 3. Relationship between field (ambient dose) and laboratory measurements (absorbed dose).

### 2.7 Geographical information system (GIS) for radioactivity monitoring

In a simple form, GIS is defined as a set of computer hardware and software designed to acquire, store, manipulate, display, and report geographically referenced information for a particular purpose in space. The space is presented by geographic coordinate systems. Therefore, GIS defines the relationships between various database information and geographical locations within the location system. Together with geostatistical tools, GIS is useful to interpolate scatter data by converting measured points into continuous surfaces. There are several methods available, the choice of which depends on the data itself. Among these methods it is worth to mention two methods, namely, inverse distance weighting (IDW) and kriging.

### 2.7.1 Inverse distance weighting (IDW)

locations for laboratory analyses of 238U, 232Th, and 40K in the collected samples. Ambient dose rates (DC) are calculated from the measurements using Eq. (2):

where AU, ATh, and AK are the activity concentrations (Bq/kg) of 238U, 232Th,

As shown in Figure 3, a very good linear relationship between field and laboratory measurements (calculated absorbed dose) was clearly perceived for about 100 data points with moderate dose rates (DC ≈ 0.7DF, R2 = 0.97). Of course, this result could be validated with more measurements. The most important outcome of that investigation is that at normal situations where the absorbed dose is up to 300 nGy/ h, the field measurements have good agreement with laboratory measurements. It is therefore safe to rely on the portable devices for routine monitoring. The implication of that is that many measurements could be performed in a field mission (as the measurement takes only few minutes long). If levels are high, then sampling and

The level of background radiation can be used as a consideration in remedial actions if contamination occurs. If measured constantly, it gives info about the trends with time and impact of man-made activities. Hence, it is important to carry out systematic investigations on ambient gamma dose throughout to establish a baseline database for future control assessment where it acts as early warning

The early warning system is composed of detectors installed at different locations and connected to central server over available communication system. Any type of detector or survey meters could be installed and used to fulfill the requirements. The advantage of this system is that the authority can create a national radiation map, showing environmental radiation levels (gross count of the radioactivity) throughout certain area updated in real time. It allows the citizen (or anyone) to see

and 40K, respectively [11].

Ionizing and Non-ionizing Radiation

laboratory measurements force itself.

system.

Figure 3.

186

2.6 Real-time radiation monitoring in the environment

what radiation levels are within that specific area at any instance.

Relationship between field (ambient dose) and laboratory measurements (absorbed dose).

D nGy=<sup>h</sup> <sup>¼</sup> <sup>0</sup>:4 61AU <sup>þ</sup> <sup>0</sup>:623ATh <sup>þ</sup> <sup>0</sup>:0414AK (2)

In this interpolator, the data points are weighted during process so that the impact of points relative to each other is a function of inverse distance. Weighting is calculated to data via the use of a weighting power and the radius object. Larger power means that the adjacent points have the larger influence. Searching radius could be fixed or variable (with typical values of power around two). This flexibility allows controlling the interpolation, which may depend on the number of samples and how they are spatially distributed. One of the drawbacks using this method is that maxima and minima are always among data points since the inverse distance weighted interpolation is a smoothing technique by definition. On the other hand, it is a powerful interpolation technique which leads to reasonable predictions with no problem with results exceeding the range of meaningful values. Simple or advance GIS software could be employed to interpolate and validate the results. Validations are normally expressed as root mean squares error in the correlation between the predicted and actual values.

### 2.7.2 Kriging method

This is an advance method that makes a surface from scattered points. It is sometimes called weighted moving averaging method because it is derived from regionalized variable theory. It assumes that the variation of a parameter is statistically correlated all over the area. Kriging derives weights from semivariogram functions that depict the degree of spatial correlation between data points as a function of distance and directions between points. The semivariogram adjusts the way kriging weights are allocated to each data point during interpolation. The semivariogram γ(h) function is given by Eq. (3):

$$\chi(h) = \frac{1}{2N(h)} \sum\_{i=1}^{N} \sqrt{\left[ Z(\mathbf{x}\_i + h) - Z(\mathbf{x}i) \right]^2} \tag{3}$$

where xi + h and xi are sampling position separated by a vector h, Z(xi) is a random variable at fixed position xi, and N(h) is the number of data pairs separated by a vector h. Ordinary kriging is a type of kriging that uses the sampled main variable to estimate values at unsampled locations. Cokriging, on the other hand, allows secondary variables to be incorporated in the model assuming that both primary and secondary variables are correlated [17, 18].

### 2.7.3 Example of prediction

Figure 4 shows a typical example to predict unsampled places from randomly scattered data points of measured ambient dose (figure to the left). Both interpolator methods IDW and kriging were used to create continuous surface of this parameter as shown in middle and right figures, respectively. These maps (easy to visualize if there are trends) could be used as a guide for any future studies; it can be improved and updated.

per sievert] and genetic defects). For people living in a certain area, the annual

E mSv=<sup>y</sup> <sup>¼</sup> D nGy=<sup>h</sup> � 24 h � <sup>365</sup>:25 d � <sup>0</sup>:<sup>2</sup> � <sup>0</sup>:7 Sv=Gy (4)

where 0.7 is the absorbed/ambient dose conversion factor and 0.2 is the outdoor

Example 1: About 100 soil samples were collected from an area, measured by gamma spectrometry which showed the following average results: 80 � 7, 91 � 21, and 573 � 89 (Bq/kg) for 238U, 232Th, and 40K, respectively. Estimate the annual effective dose for people living in this area spending 60% of their

D = 0.461x80 + 0.623x91 + 0.0414x573 = 117 nGy/h

E ≈ 0.3 mSv/y

ATh 259 þ AK

ELCR ¼ E � DL � RF (6)

<sup>4810</sup> (5)

effective dose could be calculated using Eq. (4) [12]:

Environmental Radiation: Natural Radioactivity Monitoring

DOI: http://dx.doi.org/10.5772/intechopen.85115

Solution: First we calculate the absorbed dose using Eq. (2):

This index is calculated using Eq. (5) [19]:

Hex <sup>¼</sup> <sup>80</sup> <sup>370</sup> <sup>þ</sup> <sup>91</sup> <sup>259</sup> <sup>þ</sup> <sup>573</sup>

2.9.3 Excess lifetime cancer risk (ELCR)

This can then be converted into annual effective dose using Eq. (4):

Hex <sup>¼</sup> ARa

Example 2: In example 1 above, calculate the external hazard index.

less than unity (the recommended limit for external exposure).

Cancer risk can be estimated using Eq. (6) [12, 20]:

each sievert [21], which is of order 0.05 for the public.

370 þ

<sup>4810</sup> = 0.69,

where DL is the life expectancy (in years) and RF is the cancer risk factor for

Assuming the average life expectancy of people in this area is 65 years, then using Eq. (6) the lifetime

ELCR = 0.3 � <sup>10</sup>�<sup>3</sup> � <sup>65</sup> � <sup>5</sup> � <sup>10</sup>�<sup>2</sup> = 9.8 � <sup>10</sup>�<sup>4</sup> <sup>≈</sup> <sup>10</sup>�<sup>3</sup>

The chapter describes the importance of radioactivity monitoring to preserve our environment. It sheds the light on methods designated for the measurement of

Example 3: In example 1 above, estimate cancer risk for a person living in that area.

occupancy.

time indoor.

Solution:

Solution:

3. Conclusion

189

cancer risk is calculated as

2.9.2 External hazard index (hex)

### 2.8 Radon monitoring

Radon is a naturally occurring radionuclide that is found in the environment as a member of the natural decay series of uranium. The 222Rn, including its progeny, is one of the most significant natural sources from a viewpoint of human radiation exposure to the population. Exposure to high concentrations of radon has been correlated to lung cancers, although the effect of low radiation doses is not well defined. The importance of environmental 222Rn data were pointed out in the UNSCEAR reports [11–13]. As an alpha emitter, the indoor 222Rn can be measured using detectors that estimate alpha particles or via its decay products that emit alpha, beta, or gamma rays. Many techniques have been developed to measure radon in the environment. Charcoal canister technique and solid-state nuclear track detector (SSNTD) are common methods in use to evaluate radon in passive mode. The radiation doses due to radon inhalation are calculated according to the ICRP assumption of equilibrium factor (the quotient of the equilibrium equivalent concentration to the 222Rn concentration) of 0.4 and assuming 5700 h spent indoors annually.

### 2.9 Assessment of external hazards

In addition to absorbed dose calculated from Eq. (2), the following additional hazard index parameters are, generally, evaluated using field or laboratory measurements to assess the risk of exposure due to natural radioactivity.

### 2.9.1 Annual effective dose (E)

The annual effective dose is a quantity that is introduced in the field of radiation protection for dose limitation, defined as organ or tissue weighted sum of equivalent dose in 1 year (averaged for the whole body) considering type of radiation. It represents the stochastic risk (probability of getting cancer [estimated as 5 <sup>10</sup><sup>2</sup>

### Figure 4.

Converting scattered measured ambient dose to continuous surface using inverse distance weighting (IDW) and kriging geostatistical methods.

per sievert] and genetic defects). For people living in a certain area, the annual effective dose could be calculated using Eq. (4) [12]:

$$\mathbf{E(mSv/y)} = \mathbf{D(nGy/h)} \times \mathbf{24 h} \times \mathbf{365.25 d} \times \mathbf{0.2} \times \mathbf{0.7} \text{ (Sv/Gy)}\tag{4}$$

where 0.7 is the absorbed/ambient dose conversion factor and 0.2 is the outdoor occupancy.

Example 1: About 100 soil samples were collected from an area, measured by gamma spectrometry which showed the following average results: 80 � 7, 91 � 21, and 573 � 89 (Bq/kg) for 238U, 232Th, and 40K, respectively. Estimate the annual effective dose for people living in this area spending 60% of their time indoor. Solution: First we calculate the absorbed dose using Eq. (2): D = 0.461x80 + 0.623x91 + 0.0414x573 = 117 nGy/h This can then be converted into annual effective dose using Eq. (4): E ≈ 0.3 mSv/y

### 2.9.2 External hazard index (hex)

2.7.3 Example of prediction

Ionizing and Non-ionizing Radiation

improved and updated.

2.8 Radon monitoring

annually.

Figure 4.

188

kriging geostatistical methods.

2.9 Assessment of external hazards

2.9.1 Annual effective dose (E)

Figure 4 shows a typical example to predict unsampled places from randomly scattered data points of measured ambient dose (figure to the left). Both interpolator methods IDW and kriging were used to create continuous surface of this parameter as shown in middle and right figures, respectively. These maps (easy to visualize if there are trends) could be used as a guide for any future studies; it can be

Radon is a naturally occurring radionuclide that is found in the environment as a member of the natural decay series of uranium. The 222Rn, including its progeny, is one of the most significant natural sources from a viewpoint of human radiation exposure to the population. Exposure to high concentrations of radon has been correlated to lung cancers, although the effect of low radiation doses is not well defined. The importance of environmental 222Rn data were pointed out in the UNSCEAR reports [11–13]. As an alpha emitter, the indoor 222Rn can be measured using detectors that estimate alpha particles or via its decay products that emit alpha, beta, or gamma rays. Many techniques have been developed to measure radon in the environment. Charcoal canister technique and solid-state nuclear track detector (SSNTD) are common methods in use to evaluate radon in passive mode. The radiation doses due to radon inhalation are calculated according to the ICRP assumption of equilibrium factor (the quotient of the equilibrium equivalent concentration to the 222Rn concentration) of 0.4 and assuming 5700 h spent indoors

In addition to absorbed dose calculated from Eq. (2), the following additional hazard index parameters are, generally, evaluated using field or laboratory mea-

The annual effective dose is a quantity that is introduced in the field of radiation protection for dose limitation, defined as organ or tissue weighted sum of equivalent dose in 1 year (averaged for the whole body) considering type of radiation. It represents the stochastic risk (probability of getting cancer [estimated as 5 <sup>10</sup><sup>2</sup>

Converting scattered measured ambient dose to continuous surface using inverse distance weighting (IDW) and

surements to assess the risk of exposure due to natural radioactivity.

This index is calculated using Eq. (5) [19]:

$$H\_{c\chi} = \frac{A\_{Ra}}{370} + \frac{A\_{Th}}{259} + \frac{A\_K}{4810} \tag{5}$$

Example 2: In example 1 above, calculate the external hazard index. Solution: Hex <sup>¼</sup> <sup>80</sup> <sup>370</sup> <sup>þ</sup> <sup>91</sup> <sup>259</sup> <sup>þ</sup> <sup>573</sup> <sup>4810</sup> = 0.69, less than unity (the recommended limit for external exposure).

### 2.9.3 Excess lifetime cancer risk (ELCR)

Cancer risk can be estimated using Eq. (6) [12, 20]:

$$\text{ELCR} = \text{E} \times \text{DL} \times \text{RF} \tag{6}$$

where DL is the life expectancy (in years) and RF is the cancer risk factor for each sievert [21], which is of order 0.05 for the public.

Example 3: In example 1 above, estimate cancer risk for a person living in that area. Solution:

Assuming the average life expectancy of people in this area is 65 years, then using Eq. (6) the lifetime cancer risk is calculated as

ELCR = 0.3 � <sup>10</sup>�<sup>3</sup> � <sup>65</sup> � <sup>5</sup> � <sup>10</sup>�<sup>2</sup> = 9.8 � <sup>10</sup>�<sup>4</sup> <sup>≈</sup> <sup>10</sup>�<sup>3</sup>

### 3. Conclusion

The chapter describes the importance of radioactivity monitoring to preserve our environment. It sheds the light on methods designated for the measurement of natural radionuclides in the environment and assessment of radiation exposure to human in different situations. In addition to measurements and surveys, the chapter presents a summary of some methods of radiation dose calculations that the individual may be exposed to. As is difficult to measure everywhere, the chapter also presents methods for estimating and predicting the spatial distribution of radiological quantities. The use of a geographical information system, GIS, and geostatistical methods to create maps facilitates the evaluation and assessment of radioactivity in the environment. Environmental measurements may be costly and time-consuming practices; hence, thoughts to reduce time and efforts are given in this chapter where at normal levels portable simple equipment proved useful.

References

1519-1522

76:672

73:233-245

166-171

1103-1112

1344-1350

191

Nature. 2015;517:356-359

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DOI: http://dx.doi.org/10.5772/intechopen.85115

Environmental Radiation: Natural Radioactivity Monitoring

rates and radioactivity in Tanzania. Health Physics. 2002;82(1):80-86

[9] Beamish D. Environmental radioactivity in the UK: The airborne geophysical view of dose rate estimates. Journal of Environmental Radioactivity.

[10] Jeevarenuka K, Sankaran PG, Hameed PS, Mathiyarasu R. Evaluation

of natural gamma radiation and absorbed gamma dose in soil and rocks of Perambalur district (Tamil Nadu, India). Journal of Radioanalytical and Nuclear Chemistry. 2014;302:245-252

[11] UNSCEAR. Sources and Effects of

Ionizing Radiation. New York:

[12] UNSCEAR. Effects of Atomic Radiation to the General Assembly. New

York: United Nations scientific committee on the effect of atomic

[13] UNSCEAR (United Nations Scientific Committee on the Effect of Atomic Radiation). Sources and Effects of Ionizing Radiation. New York, United Nation: Report to the General Assembly;

[14] IAEA. Measurement of Radionuclides in Food and the Environment, a Guidebook. Vienna: International Atomic Energy Agency; 1989. Technical Report Series No. 295

ray spectrometry data; 2003

[15] IAEA-TECDOC-1363. Guidelines for radioelement mapping using gamma

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[17] Salih I, Pettersson HBL, Lund E, Ake S. Spatial correlation between radon

222Rn) in groundwater and bedrock uranium (238U): GIS and geostatistical

2014;138:249-263

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radiation; 2000

2008

(

[2] Collerson KD, Kamber BS. Evolution of the continents and the atmosphere inferred from Th-U-Nb systematics of the depleted mantle. Science. 1999;283:

[3] Abdalhamid S, Salih I, Idriss H. Gamma absorbed radiation dose in Marrah mountain series, western Sudan. Environment and Earth Science. 2017;

[4] Malczewski D, Teper L, Dorda J.

anthropogenic radioactivity levels in rocks and soils in the environs of Swieradow Zdrojin Sudetes, Poland, by in situ gamma-ray spectrometry. Journal of Environmental Radioactivity. 2004;

[5] Sohrabi M. World high background natural radiation areas: Need to protect

public from radiation exposure. Radiation Measurements. 2013;50:

[6] Rafique M, Khan AR, Jabbar A, Rahman SU, Kazmi SJA, Nasir T, et al. Evaluation of radiation dose due to naturally occurring radionuclides in rock samples of different origins collected from Azad Kashmir. Russian Geology and Geophysics. 2014;55(9):

[7] Al-Sulaiti H, Nasir T, AlMugren KS, Alkhomashi N, Al-Dahan N, Al-Dosari M, et al. Determination of the natural radioactivity levels in north west of Dukhan, Qatar using high-resolution gamma-ray spectrometry. Applied Radiation and Isotopes. 2012;70:

[8] Banzi FP, Msaki P, Makundi IN. A survey of background radiation dose

Assessment of natural and

### Acknowledgements

Part of the data presented in this chapter is prepared with the support of the "Environmental group of Sudan Atomic Energy Commission." The author would like to thank all members of this group for their collaboration during field missions, laboratory analyses, and reporting.

### Conflict of interest

The author discloses no potential conflicts of interest.

### Author details

Isam Salih Mohamed Musa1,2\*

1 Physics Department, College of Science, Taibah University, Medina, Saudi Arabia

2 Radiation Safety Institute, Atomic Energy Commission, Khartoum, Sudan

\*Address all correspondence to: isamsalih@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Environmental Radiation: Natural Radioactivity Monitoring DOI: http://dx.doi.org/10.5772/intechopen.85115

### References

natural radionuclides in the environment and assessment of radiation exposure to human in different situations. In addition to measurements and surveys, the chapter presents a summary of some methods of radiation dose calculations that the individual may be exposed to. As is difficult to measure everywhere, the chapter also presents methods for estimating and predicting the spatial distribution of radiological quantities. The use of a geographical information system, GIS, and geostatistical methods to create maps facilitates the evaluation and assessment of radioactivity in the environment. Environmental measurements may be costly and time-consuming practices; hence, thoughts to reduce time and efforts are given in this chapter where at normal levels portable simple equipment proved useful.

Part of the data presented in this chapter is prepared with the support of the "Environmental group of Sudan Atomic Energy Commission." The author would like to thank all members of this group for their collaboration during field missions,

1 Physics Department, College of Science, Taibah University, Medina, Saudi Arabia

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 Radiation Safety Institute, Atomic Energy Commission, Khartoum, Sudan

\*Address all correspondence to: isamsalih@gmail.com

provided the original work is properly cited.

Acknowledgements

Ionizing and Non-ionizing Radiation

Conflict of interest

Author details

190

Isam Salih Mohamed Musa1,2\*

laboratory analyses, and reporting.

The author discloses no potential conflicts of interest.

[1] Andersen MB, Elliott T, Freymuth H, Sims KWW, Niu Y, Kelley KA. The terrestrial uranium isotope cycle. Nature. 2015;517:356-359

[2] Collerson KD, Kamber BS. Evolution of the continents and the atmosphere inferred from Th-U-Nb systematics of the depleted mantle. Science. 1999;283: 1519-1522

[3] Abdalhamid S, Salih I, Idriss H. Gamma absorbed radiation dose in Marrah mountain series, western Sudan. Environment and Earth Science. 2017; 76:672

[4] Malczewski D, Teper L, Dorda J. Assessment of natural and anthropogenic radioactivity levels in rocks and soils in the environs of Swieradow Zdrojin Sudetes, Poland, by in situ gamma-ray spectrometry. Journal of Environmental Radioactivity. 2004; 73:233-245

[5] Sohrabi M. World high background natural radiation areas: Need to protect public from radiation exposure. Radiation Measurements. 2013;50: 166-171

[6] Rafique M, Khan AR, Jabbar A, Rahman SU, Kazmi SJA, Nasir T, et al. Evaluation of radiation dose due to naturally occurring radionuclides in rock samples of different origins collected from Azad Kashmir. Russian Geology and Geophysics. 2014;55(9): 1103-1112

[7] Al-Sulaiti H, Nasir T, AlMugren KS, Alkhomashi N, Al-Dahan N, Al-Dosari M, et al. Determination of the natural radioactivity levels in north west of Dukhan, Qatar using high-resolution gamma-ray spectrometry. Applied Radiation and Isotopes. 2012;70: 1344-1350

[8] Banzi FP, Msaki P, Makundi IN. A survey of background radiation dose

rates and radioactivity in Tanzania. Health Physics. 2002;82(1):80-86

[9] Beamish D. Environmental radioactivity in the UK: The airborne geophysical view of dose rate estimates. Journal of Environmental Radioactivity. 2014;138:249-263

[10] Jeevarenuka K, Sankaran PG, Hameed PS, Mathiyarasu R. Evaluation of natural gamma radiation and absorbed gamma dose in soil and rocks of Perambalur district (Tamil Nadu, India). Journal of Radioanalytical and Nuclear Chemistry. 2014;302:245-252

[11] UNSCEAR. Sources and Effects of Ionizing Radiation. New York: UNSCEAR; 1993

[12] UNSCEAR. Effects of Atomic Radiation to the General Assembly. New York: United Nations scientific committee on the effect of atomic radiation; 2000

[13] UNSCEAR (United Nations Scientific Committee on the Effect of Atomic Radiation). Sources and Effects of Ionizing Radiation. New York, United Nation: Report to the General Assembly; 2008

[14] IAEA. Measurement of Radionuclides in Food and the Environment, a Guidebook. Vienna: International Atomic Energy Agency; 1989. Technical Report Series No. 295

[15] IAEA-TECDOC-1363. Guidelines for radioelement mapping using gamma ray spectrometry data; 2003

[16] Available from: https://www.pinte rest.com/pin/186406872046885328/

[17] Salih I, Pettersson HBL, Lund E, Ake S. Spatial correlation between radon ( 222Rn) in groundwater and bedrock uranium (238U): GIS and geostatistical

analyses. Journal of Spatial Hydrology. 2002;2(2):1-10

[18] Salih I. Radon in Natural Waters, Analytical Methods; Correlation to Environmental Parameters; Radiation Dose Estimation; and GIS Applications. PhD thesis. Sweden: Linkoping University; 2003. ISBN: 91-7373-510-8; ISSN: 0345-0082

[19] Gulan L, Milenkovic B, Zeremski T, Milic G, Vuckovic B. Persistent organic pollutants, heavy metals and radioactivity in the urban soil of Priština City, Kosovo and Metohija. Chemosphere. 2017;171:415-426

[20] Chandrasekaran A, Ravisankar R, Senthilkumar G, Thillaivelavan K, Dhinakaran B, Vijayagopal P, et al. Spatial distribution and lifetime cancer risk due to gamma radioactivity in Yelagiri Hills, Tamilnadu, India. Egyptian Journal of Basic and Applied Sciences. 2014;1(1):38-48

[21] International Commission on Radiological Protection ICRP. Recommendations of the ICRP. New York: Pergamon Press; 1990. ICRP Pub No. 60

analyses. Journal of Spatial Hydrology.

Ionizing and Non-ionizing Radiation

[18] Salih I. Radon in Natural Waters, Analytical Methods; Correlation to Environmental Parameters; Radiation Dose Estimation; and GIS Applications.

University; 2003. ISBN: 91-7373-510-8;

[19] Gulan L, Milenkovic B, Zeremski T, Milic G, Vuckovic B. Persistent organic

radioactivity in the urban soil of Priština

[20] Chandrasekaran A, Ravisankar R, Senthilkumar G, Thillaivelavan K, Dhinakaran B, Vijayagopal P, et al. Spatial distribution and lifetime cancer risk due to gamma radioactivity in Yelagiri Hills, Tamilnadu, India. Egyptian Journal of Basic and Applied

PhD thesis. Sweden: Linkoping

pollutants, heavy metals and

City, Kosovo and Metohija. Chemosphere. 2017;171:415-426

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No. 60

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[21] International Commission on Radiological Protection ICRP. Recommendations of the ICRP. New York: Pergamon Press; 1990. ICRP Pub

2002;2(2):1-10

ISSN: 0345-0082

## *Edited by Otolorin Adelaja Osibote*

This book provides readers with comprehensive details on the management and measures to protect health against risks to people and environments generated by the use of ionizing and non-ionizing radiation. This book is divided into three sections, namely, Radiation Protection and Measurement; Radiation Therapy; and Radioactivity. The first section covers ionizing radiation protection; population exposure to non-ionizing density; and the system of dosimetry quantities for use in emergency preparedness and response to nuclear or radiological accidents. The second section covers various planning techniques for spinal stereotactic body radiotherapy and the application of radiation technology in the development of a malaria vaccine. The third section discusses environmental radioactivity monitoring using efficient measurements and the assessment of radiation exposure to humans. Also in this section is the evaluation of the effects of chronic radiation exposure on the testes of mice after a nuclear power plant accident.

Published in London, UK © 2020 IntechOpen © noLimit46 / iStock

Ionizing and Non-ionizing Radiation

Ionizing and Non-ionizing

Radiation

*Edited by Otolorin Adelaja Osibote*