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目的研究低剂量水平下氚水β射线的生物效应。方法人体外周血与氚水混合,分别培养24 h和48 h,72 h后收获细胞。通过染色体非稳定性畸变的变化,得到与氚水作用后染色体畸变的频率,以60Coγ射线照射后的细胞效应作为参照,得到相同剂量下氚水的相对生物效应值。结果拟合实验结果得到氚水β射线的最佳回归方程是Y=0.001+0.062D+0.053D2;比较氚水与γ射线的最佳回归方程可知,方程系数的主要区别在a值,氚水β射线的RBE最大值为2.21出现在0.06 Gy,随着剂量的增大RBE值先减小而后稳定。低剂量情况下淋巴细胞微核剂量-效应关系符合线性拟合方程Y=C+αD,得到60Coγ射线对HTOβ射线诱发微核的RBE值在1.46~2.17之间,与染色体畸变所得RBE值及变化趋势一致。结论在低剂量情况下,β射线诱发畸变的能力更强,HTOβ射线在一个电离辐射径迹上使两个染色单体各产生一个损伤的效率更高。
Objective To study the biological effects of tritiated water β-rays at low dose levels. Methods Human peripheral blood was mixed with tritiated water and cultured for 24 h and 48 h, respectively. Cells were harvested 72 h later. According to the change of chromosomal aberrations, the frequency of chromosomal aberration after the interaction with tritiated water was obtained. The relative biological effects of tritiated water at the same dose were obtained by using the cell effect after 60Coγ-ray irradiation as a reference. Results The best regression equation of the β-ray of tritiated water obtained by the fitting experiment is Y = 0.001 + 0.062D + 0.053D2. Comparing the best regression equation between tritiated water and γ-ray, the main difference between the equation coefficients is a value, tritiated water The RBE maximum of β-ray was 2.21 at 0.06 Gy, and the value of RBE decreased first and then stabilized with the increase of dose. The dose-effect relationship of micronucleus of lymphocytes in low dose accorded with the linear fitting equation Y = C + αD, and the RBE value of 60Coγ-ray to HTOβ-ray induced micronucleus was between 1.46 and 2.17. The same trend. Conclusions β-rays are more capable of inducing aberrations at lower doses and HTOβ rays are more efficient at producing one lesion on each of two chromatids on an ionizing radiation track.