CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS.

CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS.
Phys Med Biol. 2017 Dec 19;:
Authors: Arce P, Lagares JI
Abstract
We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN 2100 linear accelerator by the procedure of adjusting the initial beam parameters to fit the Percentage Depth Dose and Cross Profile Dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2x2 cm2 to 40x40 cm2, a small phantom voxel size and high statistics, a fine precision in the determination of the beam parameters have been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting a thorough CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS.
PMID: 29256451 [PubMed - as supplied by publisher]

Source: Physics in Medicine and Biology - December 19, 2017 Category: Physics Authors: Arce P, Lagares JI Tags: Phys Med Biol Source Type: research