Radiosensitization of C3H mouse mammary tumours by a 2-nitroimidazole drug

Local tumour control has been determined at 150 days after single doses of 240 kV x-rays given with or without 1 mg/g body weight of the hypoxic cell radiosensitizer Ro-07-0582. The dose required to control 50% of the tumours (TCD50) was reduced from 4380 to 2410 rad, yielding an enhancement ratio of 1·82 ± 0·07 s.e.mean. This compares favourably with the corresponding single dose gain factor for fast neutrons, which was about 1·7.