The Effects of Magnetic Field along with Nanoparticles on DNA Damage Induced by a Carbon Beam: A Monte Carlo Study

Gold and superparamagnetic iron oxide nanoparticles (NPs) have been used as dose enhancement agents in radiation therapy. Dose enhancement of these nanoparticles with the presence of a magnetic field (MF) should be investigated, due to the development of magnetic resonance imaging systems integrated with radiation therapy delivery. In this study, a cell with a DNA model irradiated by a carbon beam of 130 MeV/n and 300 MeV/n energy were simulated using Geant4-DNA Monte Carlo code. A transverse MF of 0 T, 1.5 T and 3 T was defined as a global MF. The dose enhancement ratio (DER) of NPs with and without the presence of a MF was calculated. Furthermore, single and double strand breaks of DNA was measured with and without the presence of a MF. Although a 3 T MF with the presence of gold NPs increase the dose, it does not affect the number of DNA damages. The NPs mentioned as dose-enhancing agents, can be used in MRI-guided carbon-beam radiotherapy.