目的　用胞质分裂阻滞微核法 (CBMN)对河南“4 2 6”6 0 Co源辐射事故中 3例受照者进行生物剂量估算。方法　照后 10d取血培养 ,0 3ml全血加入到 4ml培养基中 ,37℃培养 44h加松胞素B最终浓度为 6mg·L- 1 ,继续培养 2 8h收获制片 ,CBMN以千分数表示。结果　根据照后 10dCBMN频率估算受照者“梅”、“天”和“旺”的生物学剂量分别为 5 45Gy、2 84Gy和 2 78Gy。该剂量与染色体双 +环及物理剂量相近 ,与临床放射损伤的诊断也相符合。结论　在放射事故中检测CBMN可作为生物剂量计。 Objective To evaluate the biological dosimetry of three irradiation recipients in Henan “4 2 6” 60Co radiation source by cytosolic blockade micronuclei (CBMN). Methods After 10 days of culture, blood was taken and 0 3 ml of whole blood was added to 4 ml of culture medium. The final concentration of cytochalasin B was 6 mg · L -1 at 37 ℃ for 44 h, and the culture was continued for 2 8 h. CBMN was expressed as a thousandths . Results The biological dosages of “Mei”, “Tian” and “Wang” were estimated to be 5 45 Gy, 2 84 Gy and 2 78 Gy, respectively, according to the frequency of 10 BCCMN. The dose and chromosomal double ring + physical dose similar to the diagnosis of clinical radiation injury is also consistent. Conclusion Detection of CBMN in a radiological accident can be used as a biological dosimeter.