Abstract
Purpose : This work is in the context of Monte Carlo simulation in radiotherapy. The objective was to study the modelling of a Siemens OncorTM linear accelerator on the GATE (Geant4 Application for Tomographic Emission) platform. A dosimetric study on water phantom was used to evaluate the reliability and the accuracy of the simulation. Methods: The study had two different objectives: (a) the modelling of the accelerator on the GATE v6.0 platform, and (b) a preliminary dosimetric assessment. Computations were performed in a 70×70×70 cm3 water phantom, with a 100 cm source‐to‐axis distance. The accelerator's components and their geometrical and physical characteristics were defined according to the constructor specifications. The output data were obtained for a dosel(dose scoring voxel, Sarrut & Guigues 2008) of size 2.5×2.5×2.5 mm3 leading to a sensitive volume of 0.015 cm3. A comparative study of the absorbed dose in water calculated by simulation and measured was performed for the following criteria : Photon beam quality TPR (20, 10), i.e the dose ratio at 20 cm and 10 cm in water for a 100 cm source‐detector distance. Depth dose and dose profiles. Output factors for different field sizes. Simulations were performed using a cluster of 26 nodes, 100 CPUs, 194 GB RAM in total. Results: The user interface, based on macros and graphics, facilitates the modelling of different parts of the accelerator. The simulations results obtained with GATE showed a good agreement with actual measurement in water. For example, the photon beam quality obtained by simulation was 0.6725 while the measured one was 0.673. Conclusions: These preliminary results showed good agreement with real measurements. They also are a relevant illustration of the usefulness of GATE v6.0 in the field of radiotherapy. More complex modelling involving the dynamic 160 MLC leaves movements are underway (IMRT).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have