The high efficiency of the BGO detectors makes them a very attractive candidates to
replace NaI(Tl) detectors, which are widely used in studies of body composition. In this work,
the response functions of the BGO and NaI(Tl) detectors were determined at 0.662, 4.4, and 10.0
MeV using three different Monte Carlo codes; EGS4 1 , MCNP 2 , and PHOTON 3 . These codes
differ in their input files and transport calculations, and were used to verify the internal
consistency of the set-up and of the input data. The energy range of 0.662-10 MeV was chosen to
cover energies of interest in body-composition studies. The superior efficiency of the BGO
detectors has to be weighed against their inferior resolution, and their higher price than that of
the NaI detectors. Since the price of the BGO detectors strongly depends on the crystal’s size, its
optimization is an important component in the design of the entire system.
Response Function of the BGO and NaI(Tl) Detectors Using Monte Carlo Simulations