A CALIBRATION METHOD FOR WHOLE-BODY COUNTERS, USING MONTE-CARLO SIMULATION

A Monte Carlo simulation code was developed to estimate the counting e fficiencies in whole-body counting for various body sizes. The code co nsists of mathematical models and parameters which are categorised int o three groups: a geometrical model for phantoms and detectors, a phot on transport model, and a detection system model. Photon histories wer e simulated with these models. The counting efficiencies for five Cs-1 37 block phantoms of different sizes were calculated by the code and c ompared with those measured with a whole-body counter at NIRS (Japan). The phantoms corresponded to a newborn, a 5 month old, a 6 year old, an 11 year old and an adult. The differences between the measured and calculated values were within 6%. For the adult phantom, the differenc e was 0.5%. The results suggest that the Monte Carlo simulation code c an be used to estimate the counting efficiencies for various body size s.