The variation of OER with dose rate.
The oxygen enhancement ratio (OER) has been measured as a function of dose rate from 276 Gy/hr to 0.89 Gy/hr for V-79 cells irradiated at 23 degrees C or 37 degrees C. As dose rate is decreased, the OER initially increases, from a value of 3.0, to a maximum value of 3.7 to 4.0, at a dose rate between 20 and 60 Gy/hr. The OER subsequently decreases with further dose rate reduction to a minimum value of 2.4 at the lowest dose rate. Similar experiments conducted with cells in nutrient deprived conditions exhibited a monotonic decrease in OER from 3.0 to 1.7 with dose rate reduction. These experimental findings can be understood in terms of the sublethal damage repair capability of cells under different pO2 and nutrient conditions.
D000818:Animals; D002470:Cell Survival / Q000528:radiation effects*; D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes; D006224:Cricetinae; D003412:Cricetulus; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D066298:In Vitro Techniques; D010100:Oxygen / Q000502:physiology*
D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes; D010100:Oxygen