抄録
The HeLa S3 cells were placed in the hypoxic condition by repeating the evacuation-and-N2-flushing step in a small irradiation box. The oxygen concentration in the culture medium was, then, estimated at every step of the gas exchange process and was reduced to as low as 7.0μ moles litre-1 (about 5, 300 volume or 0.225 weight ppm) within 30 minutes. The dose survival curves under various hypoxic conditions showed that, with increasing the degree of hypoxia, the Do was increased and the extrapolation number (n) was reduced.
