Monte Carlo simulation of free radical production under keV photon irradiation of gold nanoparticle aqueous solution. Part II: Local primary chemical boost

For the past two decades, gold nanoparticles (GNPs) have been investigated as a radiosensitizing agent for radiation therapy. Many theoretical studies shown that GNPs increase dose deposition keV photon irradiation, both at macro and nano-scales, due to high photon-gold interaction probability. We studied by Monte Carlo simulations production of radiolysis chemical products (O•H H2O2) following an ionization event induced 20–90 in nanoparticle (NP). focused here on primary processes occurring around nanoparticles. In micrometer range, we obtained excess species GNP ionization, compared reference water (WNP) ionization. This difference came from dominant interaction, i.e., Compton photoelectric gold, which are characterized different emitted-electron energy spectra. The overproduction could be up 5 times higher GNP, depending energy. mean concentration within 100 nm is WNPs Auger electrons when radius was equal nm. On contrary, it quite comparable 50 reveals Auger-electrons do not necessarily induce significant boost vicinity WNP. However, chance occur larger, probability than water, result, especially large GNPs, accumulation oxidative stress its vicinity.