Biological response in vitro to pulsed high dose rate electrons from a clinical accelerator

Several studies of biological response to ionizing radiation of high absorbed dose rates have been performed, often with conflicting results. The aim of this study was to establish whether a difference between irradiation at high dose rates and at more conventional dose rates could be verified. Pulsed 50 MeV electrons from a clinical accelerator were used both for the high dose rate experiments (mean dose rate: 3.8x102 Gy/s) and the reference experiments (mean dose rate: 9.6x10-2 Gy/s). In this study V-79 cells were irradiated in vitro. The experiments were carried out under both oxic and anoxic conditions. No significant difference in relative biological effectiveness (RBE) or oxygen enhancement ratio (OER) was observed at the different dose rates investigated. (orig.)