OPTIMISATION OF THE BODY COMPOSITION ANALYSER USING THE GAMMA SHIELD AND IMPROVEMENT OF ACCURACY USING ORNL ANTHROPOMORPHIC PHANTOMS

摘要

The analysis of body elements using the prompt gamma rays neutron activation method is a very useful and highly accurate method Lone, M. A., Mughabghab, S. F. and Paviotti-Corcuera, R. Development of a database for prompt gamma-ray neutron activation analysis. Summary Report of the Second Research Coordination Meeting. IAEA Headquarters. IAEA Nuclear Data Section. INDC(NDS)-424. (2001) that has many applications in different fields such as the diagnosis of specific diseases, including certain types of cancers. To protect patients from gamma rays produced by the system, an efficient strategy is to apply a gamma shield. In this study, the gamma shield was placed in three separate positions. The influence of these positions on reducing the effective dose was examined in a 5-y-old Oak Ridge National Laboratory mathematical phantom. Other parameters considered were sensitivity and coefficient of variation (CV) of thermal neutron fluence rate. With the best configuration, the total effective dose per minute (E_T) was decreased ～52 % and the sensitivity was ～ 2.03-fold higher than when no shield was present.