Abstract
A study was made on the loss of the reproductive capacity of HeLa S3 cells irradiated in vitro under both oxygenated and anoxic conditions with D-T neutrons (14 Mev) at 1, 20, 30, 150 and 400 rads/minute at 25°C and 37°C and with 180 kvp X-rays at 100 rads/minute at 37°C.
1) RBE of neutrons measured at a range of 2 to 10% survival was 2.67 ?? 2.62 under oxygenated conditions and 3.83 ?? 4.61 under anoxic conditions.
2) OER was 1.40 for neutrons and 2.16 for X-rays (gain factor was 1.54).
3) Survival rate was dependent on the dose rate of neutrons under both anoxic and oxygenated conditions.
4) There was the evidence of recovery from sublethal damage of neutron irradiation under anoxic and oxygenated conditions after 5 hours.
5) The average size of survival colonies 14 days after irradiation decreased with dose. The abortive colonies increased in number and decreased in average size with dose.
