Differences in the biological effects of in vitro irradiation by 65 MeV protons and (137)cesium gamma-rays

Using the irradiation system constructed for research in radiation biology, we have investigated the differences in the biological effects of in vitro irradiation by 65 MeV protons and by Cs-137 gamma-rays. Survival curves we re generated using V79 cells. The effects on biological parameters (SF2, RB E) of protons were greater than gamma-rays. Furthermore, H-3-thymidine inco rporation in KOSC-3 cells, which display the p53 gene mutation, was inhibit ed by protons much more than by gamma-rays. On the other hand, in bleomycin -sensitive SCCKN cells, H-3-thymidine incorporation decreased more than in bleomycin-resistant SCCTF cells, however; both were inhibited by protons mu ch more than by gamma-rays. In this study, the biological parameters and H- 3-thymidine incorporation caused by 65 MeV protons were more severe than th ose caused by Cs-137 gamma-rays.