Radiosensitization Effect of the Gold Nanoparticle in the Cell Simulated with NASIC Code

Gold nanoparticle (GNP) can be used as a radiation sensitizer in radiotherapy, and many Monte Carlo simulation studies have focused on this issue. A nanodosimetry biophysics Monte Carlo code NASIC was used in this work to study both the physical and biological radiosensitization effect of GNP in the cell environment under the irradiation of X-ray. 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 Xray 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 μm) of GNP. The variation trend of the total energy deposition in the nucleus, DSB number and cell survival fraction with X-ray energy and GNP diameter are similar, but the enhancement factors decrease with the largest values as 1.47, 1.32 and 1.14 respectively. The radiosensitization effect with 40 keV X-ray energy, 100 nm GNP diameter and GNPs distributing on the nucleus surface have advantage over other parameter values. The study results can help to understand the mechanism of radiosensitization effect and give advices on GNP clinical application in the radiotherapy.