Mapping absorption dose in proton therapy of lung cancer using MCNP-6 code

Abstract

Simulations by the MCNP6 code for proton therapy succeeded in mapping the absorbed dose in lung cancer. Proton therapy simulation using active scanning method with 9 disc-shaped sources with a diameter of 0.4 cm. Mono directional beams to cancer cells at a depth of 7.9 – 9.4 cm from the skin, while the distance from the skin to the source is 14.35 cm. Cubic cancer cells measuring (1.5 x 1.5 x 1.5) cm3 were scanned by proton beams of 94 MeV and 104 MeV. The position of the largest absorbed dose of proton therapy is the position of the formation of the Bragg peak. Evaluation of the 94 MeV proton beam showed that the Bragg peak was at a depth of 7.65 cm, meaning in front of the cancer position. While in the 104 MeV beam, the Bragg peak is at a depth of 9.15 cm or is behind the position of the placed cancer. This dose is mapped on a cross-sectional graph of cancer cells so that an overview of the dose distribution is obtained in each part of the cancer cell. While the Bragg peak position from irradiation with an energy of 104 MeV fell on the back cancer cells or at a depth of 9.15 cm from the skin surface. From the position of the Bragg peak on the two irradiation energies, it can be concluded that these two energies have not given the optimum dose to cancer cells. We require irradiation with proton energy variations or setting the distance of the source in order to achieve a good isodose in cancer cells.