Radiotoxicity after iodine-131 therapy for thyroid cancer using the micronucleus assay

使用细胞因子阻断微核治疗I- 131后对淋巴细胞的辐射损伤。体内I-131对淋巴细胞的染色体损伤可导致微核细胞增多。方法;我们研究了25例分化型甲状腺癌患者，他们接受了3.7 GBq的I- 131治疗。收集患者治疗1周后的分离淋巴细胞，按照Fenech和Morley的细胞因子阻断法进行处理。目测每500b诱导细胞微核数。作为对照，同样的患者治疗前的淋巴细胞也被研究。在一项体外研究中，三名患者的淋巴细胞在治疗后至少3个月暴露于0.25至1 Gy不等的剂量，并以相同的方法进行钉钉。结果：治疗后微核平均数目（mean*SD）较对照组（15.7* 2.7 vs. 5.4 * 1.4）显著增加（p<0.05）。由于目前和最后一次放射性碘治疗之间的间隔为6至20个月（平均11.8个月），因此未检测到I- 131对淋巴细胞的累积辐射暴露对微核频率的显著影响。在这项外照射研究中，估计25例患者的内照射吸收剂量为0.33 0.09 Gy。碘-131在体内诱导淋巴细胞微核发生频率较低，且累积碘-131对淋巴细胞微核发生频率无显著影响，因此，与3 -131治疗短期非随机损伤的观点一致。甲状腺癌患者gbq（1-131）最小且可逆。

radiation damage to lymphocytes after I- 131 therapy using the cytokines is-blocked micronucleus as s a y . The chromosomal damage to lymphocytes induced by I-131 in vivo should result in augmentation of the cells with micronuclei. Methods ; We studied 25 patients with differentiated thyroid carcinoma, who were treated with 3.7 GBq of I- 131. Isolated lymphocytes collected from patients 1 week after therapy were harvested and treated according to the cytokines is-blocked method of Fenech and Morley. Micronuclens number of micronuclei per 500b inucleated cells was scored by visual inspction. As controls, lymphocytes from the same patients before therapy were also studied. In an in vitro study, lymphocytes from three patients at least 3 months after therapy were exposed doses varying from 0.25 to 1 Gy and stud led with the same method. Results : The mean number (mean*SD) of micronuclei after treatment was significantly increased (p<0.05) as comparted to control subjects (15.7* 2.7 vs. 5.4 * 1.4). Since there was an interval ranging from 6 to 20 months (mean 11.8 months) between the present and the last radio iodine therapy, no significant effect on the frequency of micronucleus with cumulative radiation exposure of I- 131 to lymphocytes was detected. Internal radiation absorbed doses estimated for 25 patients were 0.33 0.09 Gy ln this external irradiation study. C o n c I u s i o n s : The relatively low frequency of lymphocyte micronuclei induced by iodine-13 1 in vivo and lack of significant effect on the frequency of lymphocyte micronuclei with cumulative iodine-131 s u p p o r t e d the contention t h a t short-term non-stochastic damage of this therapy with 3 .7 G B q of 1-131 in thyroid cancer patientsis minimal and reversible .