双功能制剂99Tcm-Gd-DTPA-DG的制备及在荷瘤裸鼠体内的生物分布
Synthesis and biodistribution of a bi-functional agent 99Tcm-Gd-DTPA-DG in tumor bearing nude mice
目的 通过99Tcm一步法对DTPA-DG钆盐(Gd-DTPA-DG)进行标记,并观察标记物的稳定性及在荷瘤裸鼠体内的生物分布.方法 首先合成DTPA-DG,再与Gd2O3螯合,制得Gd-DTPADG.采用1.5T超导型MR扫描仪观察Gd-DTPA-DG在荷瘤裸鼠体内的肿瘤靶向效果,用正交实验设计对Gd-DTPA-DG进行99Tcm标记,采用薄层色谱法分析标记率;用SPECT仪观察标记药物在裸鼠体内的分布.裸鼠体内注入标记药物后10,30 min和1,2,4,24 h测定血液、心、脑、肝、脾、肺、肾、小肠、肌肉、肿瘤中的%ID/g.结果 Gd-DTPA-DG在荷瘤裸鼠体内显示出良好的肿瘤靶向效果.99TcmGd-DTPA-DG的放化纯约98.5%;体外放置6 h,放化纯为96.2%.2 h时肿瘤组织显像清晰,肿瘤组织对99Tcm-Gd-DTPA-DG的摄取为(1.48±0.12)%ID/g,肿瘤与肌肉的放射性比值达2.91.结论 MRI示合成的Gd-DTPA-DG可使肿瘤强化;用99Tcm标记Gd-DTPA-DG是可行的,标记物在裸鼠体内显示出良好的肿瘤靶向性,是一种极具发展潜力的SPECT-MRI双功能制剂.
更多Objective To evaluate the stability and biodistribution of a novel SPECT-MRI bi-functional agem 99Tcm-Gd-DTPA-DG in tumor-bearing nude mice. Methods DTPA-DG was synthesized and then conjugated with Gd2O3 to generate Gd-DTPA-DG. The tumor-bearing nude mice were scanned by MRI to evaluate the tumor targeting ability of Gd-DTPA-DG. The orthogonal experiment was applied to optimize pH value of reaction medium and reaction temperature. The radiolabeling efficiency was measured by thin layer chromatography. The distribution of 99Tcm-Gd-DTPA-DG in nude mice was evaluated by scintigrapy in vivo. The % ID/g was measured at different time after intravenous injection of 99Tcm-Gd-DTPA-DG. Results The tumor was significantly enhanced by Gd-DTPA-DG with MRI. The radiochemical purity of 99Tcm-Gd-DTPADG was about 98.5% and remained 96.2% at room temperature for 6 h. The tumor was well visualized by 99TcmGd-DTPA-DG SPECT at 2 h after injection. The tumor uptake was (1.48 ±0.12) %ID/g, and the rumor to muscle radioactivity ratio was 2.91. Conclusions MRI contrast of Gd-DTPA-DG may enhance tumor detection. 99Tcm-labeled Gd-DTPA-DG may be useful for tumor imaging and might have a potential role as a SPECT-MRI bi-functional agent.
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