Fig. 1.

Surviving fraction as a function of LDR on subsequent radiation-induced cytotoxic effect. Cell cultures were exposed to low dose (75 mGy, dose rate of 3.6 cGy/min) radiation. After 8 h, the same cultures were exposed to an x-ray challenge dose of 2, 4 or 6 Gy. Clonogenic survival was measured 10–14 days post exposure for Lewis cells (A) and AG01522 (B) cell cultures