Early and late effects of fractionated irradiation of the thorax of WAG/Rij rats

Irradiations were performed with 300 kV X-rays at a dose rate of 0.9 Gy min-1. Irradiations were given in 1 to 16 fractions at 6 h intervals. For each fraction number, a specific dose was given at time intervals of 1, 2, 4 and 6 h, to get an indication of the rate of repair of sublethal damage. The overall dose range was 0 - 14 Gy. From the preliminary data obtained with varying time intervals the rate of repair appeared to be dose related and with the 4, 8 and 16 fractions employed, to be virtually complete within 6 h. This is in reasonable agreement with the Tsub(1/2) of 1.5 h as calculated by Thames et al., (1984) for LD50 in mice due to pneumonitis. (UK)