Jmr. Dealmodovar et al., DOSE-RATE EFFECT FOR DNA-DAMAGE INDUCED BY IONIZING-RADIATION IN HUMAN TUMOR-CELLS, Radiation research, 138(1), 1994, pp. 190000093-190000096
The effect of dose rate on clonogenic cell survival and DNA double-str
and breaks (DSBs) has been examined in a human bladder carcinoma cell
line, RT112, treated with ionizing radiation. Cell survival changed ma
rkedly over the range of dose rates used (0.01-1.28 Gy/min) with the c
urves becoming shallower and straighter as the dose rate was lowered.
Similarly, the number of DSBs measured by pulsed-field gel electrophor
esis (PFGE) immediately after irradiation varied with dose rate. Fewer
DSBs were detectable after low-dose-rate irradiation. However, when a
4-h repair period was allowed after irradiation, cells treated at all
dose rates exhibited approximately the same amount of damage. The fin
al level of unrejoined DSBs, as detected by PFGE, therefore does not c
orrelate with cell survival at different dose rates.