Background: The beam therapy plays an important role in the treatment of cancer, which is the most common and successful form of treatment used after surgery. In proton therapy, proton beam (PB) particles irradiate the tumor. To enhance the treatment of breast tumor it is possible to inject gold nanoparticles (GNPS) into the tumor at the same time as irradiating the PB. The aim of this paper is the simulation of the treatment of breast tumors by using PBs and injecting GNPS with different concentrations, simultaneously. Therefore, we introduce the breast phantom (BP), then we irradiate it with a proton pencil beam, which is also injected with GNPS at the same time. In order to show the enhancement of the absorbed dose in the tumor, we use MCNPX.2.6 code.
Results: The findings of our simulations show that the location of the Bragg's peak within the tumor shifts to higher depths with increasing energy. Also, by injecting GNPS in different amounts of 10, 25, 50 and 75 mg / ml with simultaneously irradiation of the PB, the rate of absorbed dose increases up to 1.75% compared to the non-injected state. Our results also show that the optimal range of proton energy that creates Bragg peaks within the tumor is between 52 to 65 MeV, which causes the creation of spread out of Bragg peak. It should be noted that the amount of absorbed dose is affected by quantities such as total stopping power, average Coulomb scattering angle, CSDA range and straggling range.
Conclusion: This work offers new insights based on the use of GNPS in the treatment of breast cancer through proton therapy and indicates that the addition of GNPS is a promising strategy to increase the killing of cancer cells while irradiating fast PBs. In fact, the results of this study confirm the ability of GNPS to enhance treatment by increasing the absorbed dose in breast tumors using proton therapy.