Room: ePoster Forums
Purpose: Monte Carlo simulations are essential methods for radiation therapy, which provide precise dose simulation for complicated clinical and research scenarios in comparing with lengthy experimental measurements. In this study, the treatment head of compact Pencil Beam Scanning (PBS) proton therapy system was modeled in detail using TOPAS (TOolkit for PArticle Simulation) Monte Carlo code and validated during commissioning process.
Methods: The treatment head of Mevion HYPERSCAN proton therapy system including eighteen energy selectors and Adaptive Apertureâ„¢ were modeled using in-house class extensions in TOPAS. The Proton beam characteristics including integrated depth dose (IDD) of pristine Bragg peak for fourteen energies and in-air beam spot sizes at five different locations for five energies were simulated using TOPAS version 3.1.2 and compared with the measurements acquiring during commissioning process.
Results: For pristine Bragg peak validation, differences in the distal range of 80% dose, width of 80% dose, and 80% to 20 % dose distal fall off for all IDD curves between measured and simulated data agreed to within 1 mm. For beam spot size validation, the spot size in both x and y direction for all different positions between measured and simulated data agreed within 10 %.
Conclusion: The treatment head of compact PBS proton system was modeled and validated. TOPAS Monte Carlo simulation of the MEVION S250i with HYPERSCAN and Adaptive Apertureâ„¢ PBS proton therapy system can be a viable tool for research and verification of the proton treatment in future.