Direct Monte Carlo Dose Calculation Using Polygon-surface Computational Human Model

Abstract

In the present study, a voxel-type computational human model was converted to a polygon-surface model, afterwhich it was imported directly to the Geant4 code without using a voxelization process, that is, without convertingback to a voxel model. The original voxel model was also imported to the Geant4 code, in order to compare thecalculated dose values and the computational speed. The average polygon size of the polygon-surface model was ~0.5cm2, whereas the voxel resolution of the voxel model was 1.981 × 1.981 × 2.0854 mm3. The results showed a goodagreement between the calculated dose values of the two models. The polygon-surface model was, however, slowerthan the voxel model by a factor of 6?9 for the photon energies and irradiation geometries considered in the presentstudy, which nonetheless is considered acceptable, considering that direct use of the polygon-surface model does notrequire a separate voxelization process.