Prediction of cell survival curves from DNA double-strand break repair data for low- and high-LET radiation.
A model developed previously (Ostashevsky 1989), was applied to calculate survival curves from the DNA double-strand break (dsb) repair data for Ehrlich ascites tumour (EAT) cells irradiated with X-rays or 3.4 MeV alpha-particles (Blöcher 1988). It is shown that the calculated curves are in agreement with experiments. The relationship between the low-dose-rate survival curve slopes for low- and high-LET radiations was obtained. Data for relatively radioresistant cells (EAT, normal fibroblasts, V-79 and CHO-K1) seem to be in agreement with the predicted numbers, while those for radiosensitive cells (AT fibroblasts and xrs-6) do not. Possible reasons for this discrepancy are discussed. In the framework of the model, three factors are important for the high RBE of alpha-particles: (1) an increased radiation yield of induced dsb; (2) a reduced dsb repair rate and (3) an increased probability of losing fragments from the DNA.
Ostashevsky
J Y
JY
Department of Radiation Oncology, SUNY-Health Science Center, Brooklyn 11203.
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor; D002470:Cell Survival; D004247:DNA / Q000032:analysis; D004260:DNA Repair; D004735:Energy Transfer / Q000528:radiation effects; D008958:Models, Molecular; D011829:Radiation Dosage; D014407:Tumor Cells, Cultured / Q000528:radiation effects
D004247:DNA