DEVELOPMENT OF A NUMERICAL MODEL FOR DETERMINING THE ELECTRON BEAM DEPTH DOSE DISTRIBUTION IN MODIFIED PLASTICS

The radiation therapy is one of the methods used for treating malignant tumors. Ionizing radiation during the interaction with tumor cells cause their destruction. However, during the radiation treatment of malignant tumors, there is inevitably a side effect on healthy cells as well. Therefore, an important task of beam therapy is to ensure optimal dose distribution, in order to minimize the impact of radiation on healthy tissues and deliver the maximum dose to the tumor. One device that allows for the formation of depth dose distribution in the patient's body is a bolus. Previously, boluses for electron beam therapy have been manufactured using three-dimensional printing methods. The aim of this study was to develop a numerical model to determine the electron beam depth dose distribution in plastics modified with metallic additives. The use of these materials enables the creation of smaller boluses, which can accelerate the manufacturing time and simplify the device fixation procedure on the patient's body. Numerical models of electron beam source and plastic boluses were developed using the GEANT4 toolkit. Numerical experiments were conducted using the Monte Carlo method. As a result of the simulation the depth dose distributions of electron beams with nominal energies of 6, 12, and 15 MeV were obtained in modified plastics with copper additives. In the future, the obtained data will allow for the selection of the thickness of the forming device created using three-dimensional printing from the studied plastics, according to the clinical task.

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