Simulation study of radiosensitization effect of gold nanoparticle with Nanodosimetry Monte Carlo Simulation Code (NASIC)

Using gold nanoparticles (GNPs) as a radiation sensitizer in radiotherapy is an international research focus.The self-developed nanodosimetry biophysics Monte Carlo code NASIC was used to study both the physical and biological radiosensitization effects of GNPs in the cell environment under the irradiation of photons. GNP-cell models were built in the simulation with single GNP in the nucleus center or four different ideal distributions of multiple GNPs. The influence of photon energy, GNP size and distribution on the energy deposition, DSB number and cell survival fraction were studied. The results show that the enhancement effect of energy deposition occurs in the vicinity (~2 m) of GNP, which is mainly due to the increase of photon interactions in the GNP. The variation trends of the total energy deposition in the nucleus, DSB number and cell survival fraction with photon energy and GNP diameter are similar, but the enhancement factors decrease with the largest values as 1.55, 1.32 and 1.14 respectively. 40 keV photon energy, 100 nm GNP diameter and GNPs distributing on the nucleus surface have advantage over other parameter values in physical and biological radiosensitization effect.