Application of Monte Carlo calculation and OEDIPE software for virtual calibration of an in vivo counting system.

OEDIPE (a French acronym standing for 'Tool for Personalized Internal Dose Assessment'), developed by IRSN, is used to perform virtual calibration of a real in vivo counting system. The system, installed recently at Le Vésinet, consists of four Broad Energy germanium detectors. CT images of Livermore torso phantom are used to create a voxel phantom after segmentation using Dosigray software. Virtual calibration using the voxel phantom was validated by the comparison of peak efficiencies between Monte Carlo calculation and phantom experiments using lung sources 152Eu and 241Am at different chest wall thickness (CWT = 19, 25, 30, 43 mm). The comparison between virtual calibration and physical phantom experiments shows that the relative deviations are within +/- 10% in the energy range of 59.5-1408 keV, and within +/- 30% for 17.5 keV photons.