~（99m）Tc标记DTPA-生物素和hIgG在正常小鼠体内分布实验

目的：探讨DTPA-生物素和hIgG的99mTc标记方法,并观察标记物在体内、外的稳定性及其在正常小鼠体内分布。方法：99mTc标记DTPA-生物素采用直接标记法,99mTc标记hIgG采用2-巯基乙醇还原法,标记率及放化纯测定采用纸层析法,并分别观察99mTc-生物素和99mTc-IgG在生理盐水（NS）中的稳定性;取24只正常小鼠,分为两组,分别经尾静脉注入99mTc-生物素和99mTc-hIgG,注入剂量为7.4MBq/100μl,于注入后1h、3h、6h、12h行SPECT显像并处死小鼠分离各脏器,测量放射性计数,计算各脏器每g组织百分注射剂量（%ID/g）。结果：99mTc标记DTPA-生物素的标记率〉80%,99mTc标记hIgG的标记率〉70%,99mTc-hIgG的放化纯〉90%;在NS中温育12h未观察到99mTc-生物素和hIgG放化纯度明显降低;体内生物分布显示99mTc-生物素肾内摄取高,主要经泌尿系统排泄;99mTc-hIgG在体内主要分布于肝、脾、肾,且在血液中存留时间较长。结论：99mTc标记DTPA-生物素和hIgG具有良好的标记率及体外稳定性,小鼠体内分布实验表明,99mTc-生物素和99mTc-hIgG体内分布的明显不同,为下一步基于亲和素-生物素系统预定位技术各组分的应用提供实验依据。

The Distributional Experiment of 99mTc Radiolabelled DTPA- biotin and hIgG in Normal Mice

Objective Explore the method,the stability of marker in vivo and in vitro on normal mice distributional experiment study of 99mTc radiolabelled DTPA-biotin and hIgG.Methods 99mTc direct radiolabelled DTPA-biotin and 2-sulphur ethanol reduction method radiolabelled hIgG,using paper chromatography determine its labeling ratio and radiochemical purity,and observed the stability of 99mTc-biotin and 99mTc-hIgG respectively in saline;99mTc-biotin and 99mTc-hIgG was injected via the tail vein into 12 mice separately,implantation dose was 200μCi/ 0.1ml,and SPECT image was obtained at 1h,3h,6h and 12h after injection,the mice were sacrificed at these time points to measure the radioactivity and calculate the %ID/g in each organ.Results The labeling ratio of 99mTc radiolabelled DTPA-biotin was over 80%,the labeling ratio of 99mTc radiolabelled hIgG was over 70%,the radiochemical purity of 99mTc radiolabelled hIgG was over 90%,and remained stable in saline at room temperature within 12h.The body biological distribution shows 99mTc-biotin was deposited mainly in the kidney,chiefly excret through the urinary system.99mTc-hIgG was deposited mainly in liver,spleen,kidneys,and the blood pool showed a sustained radioactivity.Conclusion 99mTc radiolabelled DTPA-biotin and hIgG has a good labeling ratio and stability in vitro,however 99mTc-biotin and 99mTc-hIgG has a evident different biodistribution in nomal mice,it provides an experimental evidence for the application of avidin-biotin system pretargeted technology in mice.