Repair kinetics in mouse lung: a fast component at 1.1 Gy per fraction

Four experiments to measure the half-time of repair of radiation damage in mouse lung are described. Three of these experiments used two or four doses per fraction of 3.6-9 Gy. Half-times of approximately 0.6 h were found. The fourth experiment investigated repair between the two doses in pairs of small doses given daily (26F x 1.1 Gy in 13 days). Evidence was obtained of more rapid repair between these small fractions, with a half-time of 0.30 h. Using the best methods of analysis appropriate to each experiment, the 95 per cent confidence limits for the T1/2 values at 1.1 Gy per fraction did not overlap with those for the large doses per fraction.