Development of a Geant4-based independent patient dose validation system with an elaborate multileaf collimator simulation model.

Development of a Geant4-based independent patient dose validation system with an elaborate multileaf collimator simulation model.
J Appl Clin Med Phys. 2019 Jan 23;:
Authors: Choi HJ, Park H, Shin WG, Kim JI, Min CH
Abstract
Despite the improvements in the dose calculation models of the commercial treatment planning systems (TPS), their ability to accurately predict patient dose is still limited. One of the limitations is caused by the simplified model of the multileaf collimator (MLC). The aim of this study was to develop a Monte Carlo (MC) method-based independent patient dose validation system with an elaborate MLC model for more accurate dose evaluation. Varian Clinac 2300 IX was simulated using Geant4 toolkits, after which MC commissioning with measurements was performed to validate the simulation model. A DICOM-RT interface was developed to obtain the beam delivery conditions including the hundreds of MLC motions. Finally, the TPS dose distributions were compared with the MC dose distributions for water phantom cases and a patient case. Our results show that the TPS overestimated the absolute abutting leakage dose in the closed MLC field, with about 20% more of the maximum dose than that of the MC calculation. For water phantom cases, the dose distributions inside the target region were almost identical with the dose difference of less than 2%, while the dose near the edge of the target shows difference about 10% between Geant4...

Source: Journal of Applied Clinical Medical Physics - January 23, 2019 Category: Physics Authors: Choi HJ, Park H, Shin WG, Kim JI, Min CH Tags: J Appl Clin Med Phys Source Type: research