چكيده لاتين
Despite several decades of promising therapeutic research, cancer remains one of the main causes of death worldwide. There are different methods to combat the abnormal growth of tumor and cancer cells in the tissue, the most common of which are surgery, radiotherapy, chemotherapy, or a combination of these three methods. In conventional radiotherapy, which uses high-energy photons, a beam enters the tumor from one side and exits from the other, which can affect the healthy tissue beyond the tumor; while protons release most of their energy inside the tumor and do not damage the healthy tissues around the tumor. This feature makes it possible to treat tumors located in areas near tissues sensitive to radiation and tissues that have limited access and surgery. PBCT is a new treatment method that works similar to BNCT, except that it uses the reaction of proton with boron 11, which produces three alpha particles that release an energy equivalent to 8.7 MeV at the point of reaction, which is much higher than the energy of proton beams with an energy of about 2 MeV. In addition, alpha particles have a higher biological effect coefficient (RBE), which indicates their ability to damage cancer cells. RBE of alpha particles is about 5, while RBE of proton beams is about 1.1. Therefore, PBCT can act better in cancer treatment with a stronger biological efficacy of proton beams. In this research, the GEANT-4 code was used to simulate, investigate and compare proton therapy in the absence of boron and with boron based on a certain concentration of boron in the tissue and in the energy range of 50 to 250 MeV, calculate the total absorbed dose, draw the SOBP diagram with the algorithm proportional to the depth of the tumor in the presence and absence of boron. Finally, it was concluded that boron did not have much effect on the absorbed dose and the absorbed dose at each depth was almost constant, but for values above 40% boron, this amount had a downward trend and a significant decrease in the absorbed dose was observed. Also, increasing boron in the tumor tissue will reduce the penetration depth.
