^(99)Tc^m-MIBI在小鼠肝脏细胞核内的吸收剂量分布研究

A study of microscopic dose rate distribution of ^(99)Tc^m-MIBI in the liver of mice

目的 尝试建立一种微剂量估算模式 ,评估靶细胞核对放射性药物的准确吸收剂量率。方法 以99Tcm 甲氧基异丁基异腈 (MIBI)为例 ,运用冰冻切片光镜放射自显影技术 ,观察小鼠尾静脉注射99Tcm MIBI2h后 ,肝脏内放射性药物在亚细胞水平分布情况 ,探索一种符合实际分布情况的数学模式来估算肝细胞核的微剂量率 ,并与医学内照射剂量 (MIRD)估算方式比较 ,判断两种剂量率估算方法的准确性。结果 99Tcm MIBI在肝脏亚细胞水平的分布是不均匀的 ,实际肝细胞核微剂量率数值与利用MIRD模式估算的结果差异有非常显著性 (P <0 0 1 )。结论 在99Tcm 标记药物非均匀分布情况下 ,本文作者所建立的微剂量率估算模型 ,可替代MIRD模式 。

Objective\ A microdosimetry model was tried to develop an accurate way to evaluate absorbed dose rates in target cell nuclei from radiopharmaceuticals. Methods\ Microscopic frozen section autoradiography was used to determine the subcellular locations of 99 Tc m MIBI relative to the tissue histology in the liver of mice after injection of 99 Tc m MIBI via tail for two hours,and a mathematical model was developed to evaluate the microscopic dose rates in cell nuclei.The Medical Internal Radiation Dose(MIRD) schema was also used to evaluate the dose rates at the same time,and a comparison of the results of the two methods was conducted to determine which method is better to accurately estimate microscopic dose rates. Results\ The spatial distribution of 99 Tc m MIBI in the liver of mice at subcellular level was not uniform,and the differences between the microdosimetry model and MIRD schema were significant( P <0 01). Conclusion\ The microdosimetry model established in this test could be used as a substitute for MIRD schema to evaluate the dose of not uniformly distributed 99 Tc m labeled pharmaceuticals at the microscopic level;