Estimation of Photon and Electron Specific Absorbed Fractions for Selected Organs of a Human Voxelizedphantom Using GATE Monte Carlo Package

Background The specific absorbed fraction (SAF) of energy is an essential element of internal dose assessment. Objectives Here we report a set of SAFs calculated for selected organs of ahuman computational phantom. Materials and Methods The Monte Carlo transport code GATE version 6.1 was used to simulate monoenergetic photons and electrons with energies ranging from 10 keV to 2 MeV. The particles were emitted from three source organs: the kidneys, liver, and spleen. SAFs were calculated for three target regions in the body (kidneys, liver, and spleen) and compared with the results obtained using MCNP4B and GATE/GEANT4 Monte Carlo codes. For most photon energies, the self-irradiation was higher and cross-irradiation was lower in the results obtained using GATE than those obtained usingMCNP4B. Results The results showed generally good agreement for photons and high-energy electrons, with discrepancies within -2 ± 3%. Nevertheless, significant differences were found for cross-irradiation of photons of lower energy and electrons of higher energy due to statistical uncertainties larger than 10%. The comparisons of SAF values for the human voxel phantom did not show significant differences; furthermore, the results demonstrated the usefulness and applicability of the GATE Monte Carlo package for voxel level dose calculations in non-uniform media. Conclusions The present SAF calculation for the Zubal voxel phantom is validated by comparison with the results obtained using other Monte Carlo codes.