Relative Biological Effectiveness (RBE) of 131I Radiation Relative to 60Co Gamma Rays

To assess relative biological effectiveness (RBE) of 131I radiation relative to 60Co gamma rays in glioblastoma spheroid cells. In this experimental study, glioblastoma spheroid cells were exposed to 131I radiation and 60Co gamma rays. Radiation induced DNA damage was evaluated by alkaline comet assay. Samples of spheroid cells were treated by radiation from 131I for four different periods of time to find the dose-response equation. Spheroid cells were also exposed by 200 cGy of 60Co gamma rays as reference radiation to induce DNA damage as endpoint. Resulted RBE of 131I radiation relative to 60Co gamma rays in 100 μm giloblastoma spheroid cells was equal to 1.16. The finding of this study suggests that 131I photons and electrons can be more effective than 60Co gamma rays to produce DNA damage in glioblastoma spheroid cells.