放射性碘在大鼠甲状腺内的滞留模式及剂量估算

为确定放射性碘在甲状腺内滞留模式，观察甲状腺吸收放射性碘后的生物效应，进而评价其辐射危害。方法利用活体测量方法，直接测量两个不同年龄组大鼠甲状腺内１３１Ⅰ的代谢参数。对测量数据进行处理后得到了大鼠甲状腺内１３１Ⅰ的滞留函数为三指数项函数。结果利用所得三指数项滞留函数的准确方法进行剂量估算，所得的两组动物的甲状腺平均累积吸收剂量分别为７．７Ｇｙ和１１．５Ｇｙ，而一般方法算得的大鼠甲状腺的平均累积吸收剂量比用准确方法高估了６６％～９１％。结论由于准确方法考虑到影响估算甲状腺所受剂量的一些因素，故可相对准确地反映了１３１Ⅰ所致不同年龄大鼠甲状腺的吸收剂量。

Retention pattern of radioiodine in rat thyroid and its dose evaluation

bjective To study the retention pattern of radioiodine in rat thyroid,observe the biological effect,and assess the harm of radioiodine in human beings. Methods By means of whole body counting,metabolic parameters of radioiodine for the rat thyroid were obtained.The retention equation of iodine in rat thyroid was of a three exponential function. Results By using the three-exponential function,the average accumulated absorbed doses of radioiodine for rat thyroid were estimated to be 7.7Gy and 11.5Gy,respectively.Compared with this method,the ordinary method overestimated the absorbed dose by 66%-91%. Conclusion Considering some factors affecting the dose of radioiodine in rat thyroid after injection,this method can estimate the absorbed dose of radioiodine after injection for rat thyroid of different ages.