Objective Comparing the differential influence of radiation rays on the micronucleus induction rate in peripheral lymphocyte and estimating the occupational exposure dose.
Methods The in vitro healthy human blood was irradiated at 0-1.00 Gy level with 60Co γ rays, X rays and 137Cs γ rays respectively(dose rates were 0.440, 0.073 and 0.810 Gy/min respectively). After the blood cells were cultured and harvested, the lymphocytes micronuclei were counted through CB micronuclei method, lymphocyte micronuclei dose-effect curve was constructed, and relative biological effective(RBE)values of micronucleus were derived.
Results The spontaneous rate of human lymphocyte micronucleus was very low, but after irradiation with 0.05-1.00 Gy, micronucleus frequency and micronucleus cells frequency increased in a manner correlated to the dose(P<0.01).The regression equations of dose-effect curve of micronuclear were& #374;1 = 4.847 3 + 59.342 2 D + 37.364 9 D2(60Co γ rays), & #374;2 = 1.620 9 + 55.130 8 D + 12.650 4 D2(X rays)and & #374;3 = 5.085 9 + 7.526 9 D + 37.233 0 D2(137Cs γ rays)respectively. By F test, the regression coefficient of the rate of micronuclei cells and the dose were statistically significantly(P<0.001). The curve fitting exponents were 0.982 7, 0.994 8 and 0.998 6 respectively. Statistical analysis showed that relative biological effective(RBE)values of micronucleus rate, which induced by different kinds of radiation and different energy radiation, were not the same value.
Conclusion A regression equation of doseeffect curve of peripheral lymphocyte micronucleus induced by irradiation was constructed in this laboratory and showed good degree of fitness. It could provide evidence for setting medical remedy plan and evaluating prognosis of the patient with low dose exposure. The kind and energy of radiation should be considered in combined manner.
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