megavoltage x-ray dose enhancement with gold nanoparticles in tumor bearing mice

one of the applications of gold nanoparticles (gnps) in medicine is radiation dose-enhancing effect. although there are many simulations, in vitro and in vivo evidence that gnps can enhance significantly the radiation dose effect of orthovoltage beams. these beams compared with megavoltage (mv) beams, have limited applications in radiotherapy. in order to evaluate gnps radiosensitization performance with mv beams in-vivo, we used two most clinically used x-ray beams (6 and 18 mv) with the dose of 20 gy for each mouse. intratumoral injection of 50 nm gnps with the concentration of 5 mg ml-1 was applied to melanoma tumor growing in the left leg of 7 to 8 mice in 4 control and treatment groups of c57bl/6 mice. albeit, using 10 cm plexiglass jig phantom in the beam path improved the radiation - treatments, the statistical differences between groups were not significant. according to the results, it is concluded that mice can be treated with smaller tumors and higher concentrations of gnps in mv radiation beams.