**1. Introduction**

310 Radioisotopes – Applications in Physical Sciences

Vinichuk, M.; Johanson, K.; Rydin, H. & Rosén, K. (2010a). The distribution of 137Cs, K, Rb

*Journal of Environmental Radioactivity*, Vol.101, pp. 170–176, ISSN 0265-931X Vinichuk, M.; Taylor, A.; Rosén, K. & Johanson, K. (2010b). Accumulation of potassium,

Vinichuk, M.; Rosén, K.; Johanson, K. & Dahlberg, A. (2011). Correlations between

Wallace, A. (1970). Monovalent−ion carrier effects on transport of 86Rb and 137Cs into bush

White, P. & Broadley, M. (2000). Mechanisms of caesium uptake by plants. *New Phytologist*,

Yoshida, S. & Muramatsu, Y. (1998). Concentration of alkali and alkaline earth elements in

bean plants. *Plant and Soil*, Vol.32, pp. 526–520, ISSN 0032-079X

9697

0265-931X

No.4, pp. 386-392, ISSN 0265-931X

Vol.147, pp. 241-256, ISSN 0028-646X

and Cs in plants in a Sphagnum-dominated peatland in eastern central Sweden.

rubidium and cesium (133Cs and 137Cs) in various fractions of soil and fungi in a Swedish forest. *Science of the Total Environment*, Vol.408, pp. 2543–2548, ISSN 0048-

potassium, rubidium and cesium (133Cs and 137Cs) in sporocarps of *Suillus variegatus* in a Swedish boreal forest. *Journal of Environmental Radioactivity,* Vol.102,

mushrooms and plants collected in a Japanese pine forest, and their relationship with 137Cs. *Journal of Environmental Radioactivity*, Vol.41, No.2, pp. 183–205, ISSN Determination of the elemental compositions of a human body is a useful tool for understanding general physiology relationships, diagnosing some disease and cancers. Measurements of body composition yield data about normal growth, maturity and the process of ageing.

Practically, these measurements provide standards against which departures from normality may be judged. It is necessary to define differences between genetic groups, the sexes within each group, the systematic variations with age and body size and the distribution of the seemingly random differences between individuals that remain unexplained. Knowledge of the range of normality is of value in studying trends in disease processes and monitoring the response to treatment. Body composition data may influence the choice of the most appropriate treatment of wasting illness, sepsis, trauma, renal failure and nutritional disorders. So many experimental methods employed in the measurement of the composition of the human body over the past 50 years and in the consequence a lot of techniques have been applied to determine the weight percentage of body chemical compositions.

Early methods such as hydrodensitometry and skinfold anthropometry have been superseded by dual-energy x-ray absorptiometry and bioelectrical impedance spectroscopy. Also x-ray fluorescence can give important information of clinical significance. The relatively simple, rapid and risk-free electrical methods such as multifrequency bioelectrical impedance analysis, which can be employed at the bedside, have been found to be more complicated in their interpretation. Electromagnetic methods may only measure the composition of the human body at its surface. X-ray computed tomography and magnetic resonance imaging have not yet been employed much in body composition measurements.

One of the non-destructive and the most sensitive approaches is Prompt Gamma Neutron Activation Analysis (PGNAA) method (Miri & Panjeh, 2007, Chichester, 2004, Metwally, 2004) but neutron activation facilities in practice remain available in only a few centers worldwide.

In this method the sample is excited with neutrons. When an atom in the sample captures a neutron, that atom is transformed to another nuclear state of the same element. The new atom can be radioactive. If it decays with a short half life the radioactive signal can be

Body Composition Analyzer Based on PGNAA Method 313

Fig. 1. The prompt gamma spectrum from bilateral irradiation of a male with a 252 Cf

neutron source

measured by special detectors simultaneously. So the active sample which is composed of some elements promptly releases several prompt gamma rays with various intensions and energies. The gamma rays are produced immediately and stop appearing as soon as the neutron source is removed. Ordinarily, the energy spectrum of these gamma rays is the characteristic sign of the special constituting elements.

#### **2. Whole body counting and neutron activation analysis**

In this method one of the practical measurements is total body measurement of nitrogen (TBN). A total body measurement of nitrogen provides a quantitative estimate of muscle mass and may prove of value in the assessment of patients with diseases associated with muscle wasting, for example, in malabsorption syndrome. Also the technique of in vivo neutron activation analysis has proved successful for measurement of total body calcium (TBC) (McNeill, **1973).** 

Several body elements may be measured by the following prompt gamma reactions resulting from the capture of thermal neutrons. The most abundant or useful gamma energies measureable detectors such as NaI(Tl) scintillation are:


Figure 1 shows the prompt-gamma-emission spectra from bilateral irradiation of a normal male volunteer from the shoulder to the knee (Ryde *et al.* 1989). Regions of interest for hydrogen, carbon, chlorine and nitrogen are indicated.

The abundance of gamma ray emissions from other elements necessitates the use of a high resolution semiconductor detector to determine them. The most prominent feature of the prompt-gamma emission spectrum from neutron irradiation of the human body is the fullenergy peak at 2.223 MeV from hydrogen, since these nuclei are most abundant. The gamma ray emission from nitrogen at 10.8 MeV is the highest-energy emission from any body element. Consequently it is free from any interference except background noise due to random summing of lower-energy gamma rays (at high counting rates) and neutron irradiation of the detectors. This has become the standard method for the determination of TBN, and therefore total body protein (TBPr), since nitrogen comprises 16% of protein (Mernagh *et al* 1977, Beddoe *et al* 1984, Ryde *et al* 1989, Baur *et al* 1991).

Nitrogen is a direct indicator of total body protein. A high nitrogen reading indicates healthy tissue. When this measurement is combined with measurements from the total body potassium, scientists can determine total organ and muscle mass. For online information refer o the following address (http://www.bcm.edu/bodycomplab/ivnamainpage.htm).

measured by special detectors simultaneously. So the active sample which is composed of some elements promptly releases several prompt gamma rays with various intensions and energies. The gamma rays are produced immediately and stop appearing as soon as the neutron source is removed. Ordinarily, the energy spectrum of these gamma rays is the

In this method one of the practical measurements is total body measurement of nitrogen (TBN). A total body measurement of nitrogen provides a quantitative estimate of muscle mass and may prove of value in the assessment of patients with diseases associated with muscle wasting, for example, in malabsorption syndrome. Also the technique of in vivo neutron activation analysis has proved successful for measurement of total body calcium

Several body elements may be measured by the following prompt gamma reactions resulting from the capture of thermal neutrons. The most abundant or useful gamma

Figure 1 shows the prompt-gamma-emission spectra from bilateral irradiation of a normal male volunteer from the shoulder to the knee (Ryde *et al.* 1989). Regions of interest for

The abundance of gamma ray emissions from other elements necessitates the use of a high resolution semiconductor detector to determine them. The most prominent feature of the prompt-gamma emission spectrum from neutron irradiation of the human body is the fullenergy peak at 2.223 MeV from hydrogen, since these nuclei are most abundant. The gamma ray emission from nitrogen at 10.8 MeV is the highest-energy emission from any body element. Consequently it is free from any interference except background noise due to random summing of lower-energy gamma rays (at high counting rates) and neutron irradiation of the detectors. This has become the standard method for the determination of TBN, and therefore total body protein (TBPr), since nitrogen comprises 16% of protein

Nitrogen is a direct indicator of total body protein. A high nitrogen reading indicates healthy tissue. When this measurement is combined with measurements from the total body potassium, scientists can determine total organ and muscle mass. For online information refer o the following address (http://www.bcm.edu/bodycomplab/ivnamainpage.htm).

characteristic sign of the special constituting elements.

(TBC) (McNeill, **1973).** 

**2. Whole body counting and neutron activation analysis** 

energies measureable detectors such as NaI(Tl) scintillation are:

hydrogen, carbon, chlorine and nitrogen are indicated.

(Mernagh *et al* 1977, Beddoe *et al* 1984, Ryde *et al* 1989, Baur *et al* 1991).

Fig. 1. The prompt gamma spectrum from bilateral irradiation of a male with a 252 Cf neutron source

Body Composition Analyzer Based on PGNAA Method 315

In another works we see that viable signal/background ratio can be obtained using Pu-Be neutron sources and heavy shielding of both sources and detector. (Mernagh et al.

Absorbed dose, D, is the energy imparted by ionizing radiation to matter per unit mass at a

The effective dose, *E*, which is a summation of differing risks to organs in the human body

� =����� �

Because of biological effects and absorbed dose don't always have one-to-one

And HT is the equivalent dose (in Sv) in tissue or organ, T, and is given by (Clark et al,

�� =������� �

Where wR is the radiation weighting factor (or quality factor) due to radiation of type R (for example neutron, alpha etc.) and DT,R is the absorbed dose averaged over a tissue or organ,

Radiation weighting factors (wR) for neutrons, according to ICRP Publication 60 can be chosen from either a step function or a continuous function to avoid discontinuity. The

where En is the neutron energy in MeV. Another set of new wR data, is also released from ICRP Publication 103 (ICRP 103, 2008). The new radiation weighting factors function was

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following formula (ICRP 60,1991) is used to calculate the wR continuous values:

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point given in units of J kg-1 (commonly called the Gray, Gy) (Alpen, 1998).

**6. Absorbed dose quantities and attentions** 

in units of Sieverts (Sv), is given by (Clark et al., 1993).

Table 1 lists all the tissue weighting factor based on two reports.

correspondence, so another factor called quality factor is introduced.

1977)

1993).

expressed as:

T, due to a radiation of type R.

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