应用放射自显影技术时影响剂量估算的主要因素研究

Research on the Main Factors of Dose Estimation Influenced by Autoradiography.

目的 在核医学应用中 ,大多数情况下 ,放射性药物的分布是不均匀的 ,尤其表现在细胞与亚细胞水平。因此 ,为了对细胞及亚细胞水平的剂量进行估价和分析 ,需研究其在小鼠肝脏细胞内细胞水平的分布 ,并试图建立一种数学模式估算肝细胞核的微剂量。方法 以99mTc—MIBI药为例 ,运用冰冻切片光镜放射自显影技术 ,研究其在小鼠肝脏细胞内细胞水平的分布。结果 此药在肝脏细胞水平的分布是不均匀的 ,肝细胞核微剂量数值与利用MIRD模式估算的结果差异较大。结论 利用放射自显影技术 ,结合恰当的数学模式 ,进行微剂量分析 ,不仅可以弥补MIRD模式在药物非均匀分布情况下进行剂量估算的不足 ,而且可评估临床核医学中放射性药物的放射治疗效果 ,并可为放射性药物的放射毒理细胞水平的剂量 -效应关系研究提供所需剂量数据。

Objective In most situations,the spatial locations of radiopharmaceuticals are not uniform,so that in order to estimate the dose to cells and cell nuclei is necessary.Methods Autoradio-graphy(ARG) is a method to obtain the precise spatial information of the (radiolabels,relative to the tissue histology.In the study,the microscopic locations of this)radioactive substance in the liver of mice were investigated through microscopic frozen section ARG,and a mathematical model was developed,which can be conveniently used to microdosimetry,such as estimations of the doses received by the cell nuclei in rat liver after injection of 99m Tc-MIBI via tail veins in this test.Results A comparison of the radiation dose rate estimates was conducted between the cellular dosimetry model and MIRD,revealing significant differences.Conclusion ARG was proved to be a useful approach to provide detailed spatial and dosimetric information on radiopharmaceuticals within organs so that we can evaluate precisely the effectiveness of radiotherapy and radiotoxicity and microscopic radiation-effect in nuclear medicine.In this study the influence factors of dose estimation are detail analysed and discussed.