[Effect of low-dose ionizing radiation on radiosensitivity to the next irradiation]

The action of low dose irradiation on the radiosensitivity of HeLa cells was studied. It was shown that preliminary irradiation of sells by dose of 3 cGy induces the adaptive response: decreasing of number of cells with micronuclei after posterior irradiation by doses of 2.0 and 3.0 Gy. The maximum level of the adaptive response is reached in 4 h and is observed in 3 cell cycles. When the dose of preliminary irradiation increases to 40 cGy the adaptive response is not observed, however the radiosensitivity of cells increases.