**6.2. Tissue reaction in image-guided intervention**

**5. CT fluoroscopy (CTF)**

40 Medical Imaging and Image-Guided Interventions

interval range between 3 s−<sup>1</sup>

and `12 s−<sup>1</sup>

[9].

**6. Radiation doses from image-guided intervention procedure**

dure requires longer screening time compared with orthopedic procedures.

**f.** Percutaneous transluminal angioplasty (coronary and other vessels)

**6.1. Tissue reaction during interventional procedure**

longed exposure time. These procedures are:

**c.** Thrombolytic and fibrinolytic procedures

**d.** Percutaneous transhepatic cholangiography **e.** Radio-frequency cardiac catheter ablation

**g.** Endoscopic retrograde cholangiopancreatography

**j.** Biliary drainage or urinary or biliary stone removal

**h.** Transjugular intrahepatic portosystemic shunt placement

**a.** Vascular embolization

**b.** Stent and filter placement

**i.** Percutaneous nephrostomy

Fluoroscopy screening exposure time during image-guided intervention depends upon the type of the procedure and operator skills and X-ray machine technology and machine set up. Different procedures have different screening times. Usually, cardiology intervention proce-

When X-ray radiation penetrates a tissue or a medium, it deposits energy. The energy absorbed from exposure to radiation is termed a dose. Certain interventional procedure requires pro-

The substantial advances in CT technology have led to development in CT fluoroscopy in 1993, which allows fluoroscopic image acquisition with high image quality compared to conventional fluoroscopy [7]. This development in CT technology (slip ring technology in 1980s and X-ray tubes with high anode heat storage capacity up to 30 million heat units (MHU) or 22,000 kJ) and high speed processing units and advances in reconstruction software, enabled acquisition of high image quality in a short time with lower radiation dose) [8]. CT fluoroscopy becomes popular in image-guided intervention despite of the concern regarding radiation risks due to its advantages compared with conventional fluoroscopy and surgery. CT fluoroscopy is very valuable biopsy for deep structures, stent placement, and lesion drainage. CT fluoroscopy is usually performed using the following exposure parameters: 120 kVp, 30–90 mA, scan time range from 0.5 to 1.0 s, and fluoroscopic images displayed in certain time The dose rate during fluoroscopic-guided intervention ranged between 0.02 and 0.05 Gy/minute [10]. It was estimated that the mean patient dose for cardiac catheterization is 2.5 Gy, and during percutaneous interventions, the dose may reach 6.4Gy per procedures, which is higher than the erythema dose [11]. Erythema occurs due to accumulative patient doses from multiple procedures, each of which is individually insufficient to cause injury. Most of the patients require more than one procedure within a short time such as patients with ischemic heart diseases (IHD). **Table 1** shows the tissue reaction threshold during image-guided intervention procedures using fluoroscopy. **Table 2** illustrates the biological effect on patients after exposure to certain doses. **Figures 6**–**11** show radiation-induced skin injuries due to prolonged irradiation.


**Table 1.** Tissue reaction effects of acute radiation exposure.


**Table 2.** Biological effects of radiation [11, 12].

**Figure 6.** Tissue reaction effect for a 49-year-old patient who underwent two transjugular intrahepatic portosystemic shunt (TIPS) placements and one attempted TIPS placement within a week [12].

**Figure 8.** Secondary ulceration after two months for a 69-year-old patient underwent two angioplasties of left coronary

Medical Imaging and Image-Guided Interventions http://dx.doi.org/10.5772/intechopen.76608 43

**Figure 9.** Skin telangiectasia after 2 years for a 17-year-old patient underwent two cardiac ablations procedures within

artery within 30 hr [12].

13 month [12].

**Figure 7.** Photograph of right posterolateral chest wall at 10 weeks after PTCA for a 56-year-old man with obstructing lesion of right coronary artery [12].

**Figure 8.** Secondary ulceration after two months for a 69-year-old patient underwent two angioplasties of left coronary artery within 30 hr [12].

**Figure 6.** Tissue reaction effect for a 49-year-old patient who underwent two transjugular intrahepatic portosystemic

**Figure 7.** Photograph of right posterolateral chest wall at 10 weeks after PTCA for a 56-year-old man with obstructing

shunt (TIPS) placements and one attempted TIPS placement within a week [12].

42 Medical Imaging and Image-Guided Interventions

lesion of right coronary artery [12].

**Figure 9.** Skin telangiectasia after 2 years for a 17-year-old patient underwent two cardiac ablations procedures within 13 month [12].

**7. Patient doses measurement**

**8. Quality assurance**

to be cost-effective.

**8.1. Image quality**

low level (ALARA).

tions, and application factors.

When performing radiographic examinations, patient doses can be evaluated as entrance surface air kerma (ESAK), the dose administered to the skin, where an X-ray beam enters the body, which includes the incident air kerma and backscattered radiation from exposed tissue. ESAK is measured using dosimeters or through calculations from the applied exposure factors and measurements of X-ray tube output [13]. Another method is the kerma-area product (KAP), defined as the product of the dose in air (air kerma) within the X-ray beam and the beam area, which enables the measurement of overall radiation entering a patient. KAP can be measured using an ionization chamber fitted to the X-ray tube. The two methods can be applied to calculate and monitor radiation doses for the various radiological examinations compared to guidance and diagnostic reference levels (DRLs). Many research bodies have been active in the area of DRL, including the International Atomic Energy Authority (IAEA) and International Commission on Radiological Protection (ICRP). The objective of DRLs is to aid in preventing the administration of unnecessary radiation doses to patients that do not support the clinical purpose of a radiographic exam. Each X-ray facility should set up DRLs following international guidelines with regular assessments and applications of corrective action in cases where these levels are exceeded.

Medical Imaging and Image-Guided Interventions http://dx.doi.org/10.5772/intechopen.76608 45

Quality assurance in medical imaging intends to ensure the consistent provision of prompt and accurate diagnosis of patients with minimum radiation exposure to patient and staff and

Image quality, which is defined as the exactness of representation of patient anatomy, is affected by many factors including organ of interest, imaging modality, patient, and imaging modality characteristics. Images in clinical environment are evaluated subjectively by operators (radiography technologist or radiologists) or objectively (independently of an observer opinion) by measuring certain parameters. These parameters include brightness, contrast

**Tables 4** and **5** show factors affecting patient doses during interventional procedures. Patient dose depends, among other factors, on X-ray unit technology, proper equipment design and

Optimization in diagnostic radiology signifies balancing diagnostic information (image quality) and patient dosage through identifying an image acquisition technique that maximizes the perceived information content and minimizes radiation risk or keeps it at a reasonably

The factors that affect patient dose and image quality and form the backbone of optimization in diagnostic radiology fall into three categories: facilities and equipment, operational condi-

resolution, special resolution distortion, artifact, and noise, as illustrated in **Table 3**.

utilization, proper set up of equipment parameters, and operator skills.

**Figure 10.** Radiation wound 22 months after angioplasty procedure [15].

**Figure 11.** Radiation injury in a 60-year-old woman subsequent to successful neurointerventional procedure for the treatment of acute stroke [11].
