Monte Carlo modeling of the 160 MLC on the Siemens Artiste linac and IMRT dose calculations with MCNPX

Abstract

Monte Carlo (MC) methods are considered as the most accurate dose calculation method and has become more common as a complementary method for dose verification in radiation therapy routines. The purpose of this study is to fully simulate a benchmarked Artiste head and the Siemens 160 multileaf collimator (MLC) by MCNPX 2.6 Monte Carlo code. The MC-based calculations were benchmarked against the commissioning measured data and an MLC test field. A comparison between MC-based and TPS-based dose maps was made for beams of a typical complicated IMRT plan and it was shown that the 3D gamma passing rate with criteria 3%/2mm and a dose threshold of 10% is acceptable (i.e., GPR of 97.7%). Therefore, the provided model has sufficient accuracy and feasible computation time to be used for verification of complicated IMRT plans.