The Impact of Nano-Sized Gold Particles on the Target Dose Enhancement Based on Photon Beams Using by Monte Carlo Method

Abstract

<br /><strong>Objective(s): </strong>In this study we evaluate the impact of the different aspects of Gold Nano-Particles (GNPs) on the target absorptive Dose Enhancement Factor (DEF) during external targeted radiotherapy with photon beams ranging from kilovolt to megavolt energies using Monte Carlo simulation. <br /><strong>Methods:</strong> We have simulated the interaction of photon beams with various energies of radiation using water solution containing GNPs to be located in a tumor region and used MCNP5 code for Initially, the water phantom in which a tumor dimensions of 1 × 1 × 1 cm³was defined as the target, contained simulated GNPs. Then, themacroscopic DEF of GNPs of different sizes, including 15, 50, and 100 nm, had been calculated at the target area with a fixed concentration of 7 mg/g during external beam radiotherapy with single-energy photon beams ranging from keV to MeV. <br /><strong>Result</strong><strong>s:</strong> The tumor DEFs in the presence of GNPs were obtained 1.69-2.66and 1.08-1.10 for keV and MeV beams, respectively. The highest DEF was achieved by photon energy of 50 keV. By increasing the size of the GNPs, the tumor dose factor raised too. <br /><strong>Conclusions:</strong> The factors calculated for enhancing the target dose of GNPs were in good agreements with previous studies based on keV photon energies. For MeV photon energies, after a reduction in the boundary between the two areas of water and the solution containing GNPs, the dose factor was enhanced to its maximum value for 2 and 6 MeV photon beams at the depths of 2.6 and 5.6 cm, respectively.