Enhanced electron beam and X-ray beam therapy by applying nanoparticle heterojunctions: A Monte Carlo simulation

Cancer has become one of the major diseases that seriously threaten human health. In order to improve the therapeutic gain ratio (TGF) of conventional X-ray and electron beams, we studied the dose enhancement effect and secondary electrons emission of Au-Fe nanoparticle heterostructures by Monte Carlo method. Under the irradiation of 6 MeV photon and 6 MeV electron beams, the Au-Fe mixture has a dose enhancement effect. For this reason, we explored the secondary electrons production that leads to dose enhancement. For 6 MeV electron beam irradiation, Au-Fe nanoparticle heterojunctions have an higher electrons emission than Au and Fe nanoparticles. When cubic, spherical and cylindrical heterogeneous structures are considered, the electron emission of the columnar Au-Fe nanoparticles is the highest, with a maximum value of 0.00024. For 6 MV X-ray beam irradiation, Au nanoparticle and Au-Fe nanoparticle heterojunction have similar electrons emission, while Fe nanoparticle has the lowest one. When cubic, spherical and cylindrical heterogeneous structures are considered, the electron emission of the columnar Au-Fe nanoparticles is the highest, with a maximum value of 0.000118. This study contributes to improve the tumor-killing effect of conventional X-ray radiotherapy treatment and has guiding significance for the research of new nanoparticles.