A preliminary Monte Carlo study for the treatment head of a carbon-ion radiotherapy facility using TOPAS

Abstract

Abstract. In medical physics it is desirable to have a Monte Carlo code that is less complex, reliable yet flexible for dose verification, optimization, and component design. TOPAS is a newly developed Monte Carlo simulation tool which combines extensive radiation physics libraries available in Geant4 code, easyto-use geometry and support for visualization. Although TOPAS has been widely tested and verified in simulations of proton therapy, there has been no reported application for carbon ion therapy. To evaluate the feasibility and accuracy of TOPAS simulations for carbon ion therapy, a licensed TOPAS code (version 3_0_p1) was used to carry out a dosimetric study of therapeutic carbon ions. Results of depth dose profile based on different physics models have been obtained and compared with the measurements. It is found that the G4QMD model is at least as accurate as the TOPAS default BIC physics model for carbon ions, but when the energy is increased to relatively high levels such as 400 MeV/u, the G4QMD model shows preferable performance. Also, simulations of special components used in the treatment head at the Institute of Modern Physics facility was conducted to investigate the Spread-Out dose distribution in water. The physical dose in water of SOBP was found to be consistent with the aim of the 6 cm ridge filter.

Monte-Carlo techniques for radiotherapy applications I: introduction and overview of the different Monte-Carlo codes

“…TOPAS was originally developed to facilitate the simulation of proton and carbon-ion therapy systems and has been used to develop models of passive and pencil beam scanning systems. [49][50][51] Despite its particle therapy roots, it is also able to model the more widely used photon and electron beams to the extent that an MV linac example is now included as part of the more recent releases. Examples of uses for modelling Brachytherapy sources are also provided.…”

Applications of Simulation Codes Based on Monte Carlo Method for Radiotherapy

“…The TOPAS (Tool for Particle Simulation) computational code is based on physical Geant4 models and low energy electromagnetic models of the PENELOPE code [39] and has shown great potential for simulations in medical and quality control applications [22,[40][41][42][43].…”

The influence of beam delivery uncertainty on dose uniformity and penumbra for pencil beam scanning in carbon-ion radiotherapy

“…There are already some MC simulation works for the treatment nozzle. However, these simulations for the treatment nozzle are mainly focused on proton radiotherapy, and there are comparatively fewer studies on the treatment nozzle of CIRT using other MC codes [8][9][10][11]. Nevertheless, most of these simulations mainly focused on passive CIRT.…”