Effects of X and gamma rays on human lymphocytes

The purpose of this study is to investigate the effects of different doses and doserates of X- and gamma rays on human lymphocytes. After separating mononuclear cells with lymphocytes from human peripheral blood, they were irradiated, either with X-ray doses (0.25, 0.5, 1, 2 and 4 Gy) at a dose rate of 0.28 Gy/min or with doses (15.65, 31.25, 62.5, 125 and 250 mGy) at dose rate of 20 mGy/min or with 60Co gamma ray doses (0.25, 0.5, 1, 2 and 4 Gy) at dose rate of 33 mGy/min. Using flow cytomtery the amount and percentage of apoptotic and lymphocytes were measured. In contrast to low X-ray doses with low dose rate, induction of apoptosis was significant at high X-ray doses with high dose rate. Moreover, apoptosis was significant at high gamma ray doses at low dose rate. We conclude that apoptosis is a good biological marker for radiation response, and the induction of apoptosis depends on dose, and not, on dose rate.