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目的18MeV中子和60Coγ射线照射离体人血淋巴细胞,建立染色体畸变和淋巴细胞微核的剂量-效应曲线;计算中子染色体畸变和微核的相对生物效应。方法中子和60Coγ射线照射离体人血,吸收剂量率都为0.2Gy/min,吸收剂量为0.5～3.0Gy。记录染色体型畸变和双核淋巴细胞的微核,分别对双着丝粒体+着丝粒环和微核做曲线拟合,并计算中子的RBE。结果中子和60Coγ射线照射离体人血诱发的染色体畸变(双+环)和淋巴细胞微核,呈良好的剂量-效应关系。中子诱发染色体畸变和微核的RBE值都随吸收剂量的增加而减少,在0.5～3.0Gy范围内,诱发染色体(双+环)的RBE值是3.59～1.77;诱发微核的RBE值是2.91～1.24。结论快中子照射离体人血淋巴细胞产生的染色体畸变(双+环)和微核的剂量-效应关系都符合线性平方模型。中子与60Coγ射线相比较,在照射剂量较低时,有较高的生物效应。
Objective To establish a dose-response curve of chromosomal aberrations and micronuclei in lymphocytes irradiated by 18 MeV neutrons and 60Co γ-rays, and calculate the relative biological effects of neutron chromosome aberration and micronuclei. Methods Neutrons and 60Coγ ray irradiated human blood in vitro. The absorbed dose rate was 0.2Gy / min and the absorbed dose was 0.5-3.0Gy. Chromosome aberrations and micronuclei of binuclear lymphocytes were recorded, curvilinear fitted to dicentric centromere + centromere and micronucleus respectively, and neutron RBE was calculated. Results The chromosomal aberrations (double + loop) induced by neutrons and 60Coγ-ray irradiated human blood and the micronuclei of lymphocytes showed a good dose-response relationship. RBE value of neutron-induced chromosome aberration and micronucleus decreased with the increase of absorbed dose. The RBE value of induced chromosome (double + ring) ranged from 3.59 to 1.77 in the range of 0.5-3.0 Gy. The RBE value of induced micronucleus 2.91 ~ 1.24. Conclusion The dose-effect relationship of chromosome aberration (double + ring) and micronucleus produced by fast neutron irradiation of human hematopoietic lymphocytes are in line with the linear square model. Compared with the 60Coγ ray, neutron has a higher biological effect at a lower radiation dose.