Spherical Collimation Systems Radiation Fields Monte Carlo Calculation

Abstract

Purpose: To determine the optimal parameters of the collimation system of the gamma therapeutic apparatus. Material and methods: collimation system parameters Monte Carlo simulation in Geant4 Software Package. Results: Simulation in the Geant4 software package is a reliable tool for solving such problems The good agreement between calculated and experimental data was achieved. The proposed system of spherical beam collimation using a source similar to GIK-9-3(4) (manufactured by Mayak), with a value of SSD=1000 mm, is capable of providing the required characteristics of the radiation field over the entire range of its sizes. It seems appropriate to consider the reduction of radiation leakage with the help of a jagged shape of the contacting surfaces of the collimator jaws, since the dose is mainly due to leakage through poorly connected collimator jaws, reduced to a negative angle. Conclusion: The performed calculation of the collimation system makes it possible to use the obtained results for the design of radiation heads of gamma therapeutic devices without additional scientific research. The paper also provides a detailed description of the libraries of physical processes used in Geant4, which allows the reader, if necessary, to repeat the experiment for his/her own needs.