studying effects of gold nanoparticle on dose enhancement in megavoltage radiation

background: gold nanoparticles are emerging as promising agents for cancer therapy and are being investigated as drug carriers, photothermal agents, contrast agents and radiosensitisers. objective: the aim of this study is to understand characteristics of secondary electrons generated from interaction of gold nanoparticles gnps with x-rays as a function of nanoparticle size and beam energy and thereby further understanding of gnp-enhanced radiotherapy. methods: effective range, defection angle, dose deposition, energy, and interaction processes of electrons produced from the interaction of x-rays with a gnp were calculated by monte carlo simulations. the mcnpx code was used to simulate and track electrons generated from 30 and 50 nm diameter gnp when it is irradiated with a cobalt-60 and 6mv photon and electron beam in water. results: when a gnp was present, depending on beam types used, secondary electron production increased by 10- to 2000-fold compared to absence of a gnp. conclusion: gnps with larger diameters also contributed to more doses .