Sub-Letahl Damage Repairs Efficiently After High-LET Radiation

Abstract

SLD repair after high-LET radiations were determined with low-LET X-ray beam. Chinese Hamster V79 cells were exposed to priming ion-beams having different LETs. The cells were repaired in room temperature and exposed to testing X-ray. Resulting from kinetics study, surviving fractions of the cell quickly increased with the repair time, and reached to a plateau in 3-4 hours, when cells has received 440 keV/um iron ion priming dose, as well as X-ray. The shoulder of survival curves for testing X-ray after all priming high-LET ion-beams and 3 hours repair were the same to that for acute X-ray dose. These results suggest that SLD after high-LET radiation is well repaired as low-LET radiations. Ion beam may produce lethal damages in the cell when cell was hit by core of the track. When a cell was hit by the penumbra, SLDs may be produced in the cell, because the LETs in the penumbra are low. [J Radiat Res 44:435 (2003)]