小分子肽^(99m)T_C-YIGSR与^(99m)Tc-MIBI进行肿瘤显像的对比研究

Comparison of ^(99m)Tc-YIGSR and ^(99m)Tc-MIBI in Imaging the Eldrich Ascites Tumor in Mice

目的将小分子肽YIGSR经99mTc标记后用于肿瘤受体显像并与99mTc-MIBI进行对比。方法①显像剂制备。YIGSR经双功能螯合剂S-Acetyl-MAG3偶联后室温下进行99mTc标记;99mTc-MIBI采用煮沸法制备。②取昆明种小鼠,每只皮下注射1×106埃氏腹水癌细胞以复制肿瘤模型。③经尾静脉注射显像剂后,将99mTc-YIGSR与99mTc-MIBI显像结果进行比较。结果99mTc-YIGSR肿瘤显像可见肿瘤部位自30 min开始有明显摄取,3 h达高峰,肿瘤/非肿瘤比值(T/NT)为11.36。显像剂清除缓慢,8 h T/NT降至3.01;99mTc-MIBI在肿瘤部位的浓聚明显低于99mTc-YIGSR,其T/NT比值依次为1.40(3 h)及0.55(8 h)。结论99mTc-YIGSR肿瘤显像结果优于99mTc-MIBI,作为一种特异性强的新型肿瘤受体显像剂,具有一定的应用前景。

Objective To compare the peptide fragments radiotracer 99m^Tc-YIGSR with 99m^Tc-MIBI in imaging Eldrich ascites tumor in mice. Methods By using S-Acetly-NHS-MAG3 as chelator, YIGSR was labeled with 99m^Tc at room temperature. The MIBI was boiled when labeled with 99m^Tc. The tumor-bearing mice model was prepared by inoculating 1 × 10^6 Ehrlich tumor cells in the right thigh. The tumor was allowed to grow for 7-10 days to a size of 1.0-1.5 cm in diameter. 37-74 MBq of 99m^Tc-YIGSR or 99m^Tc-MIBI was injected in the tail vein of each mouse, which was then immobilized and imaged periodically under a gamma camera. Results The 99m^Tc-YIGSR accumulation at the tumor tissue was observed clearly at 30 min and reached the climax at 3 h with a tumor to normal ratio of 11.36. As the radiotracer was slowly cleared out, the tumor/normal ratio was decreased to 3.01 at 8 h. In the 99m^Tc-MIBI group, the tumor to normal ratio was 1.40 at 3 h and 0.55 at 8 h respectively. The difference between 99m^Tc-YIGSR and 99m^Tc-MIBI imaging was significant （P〈0.01）. Conclusion The high sensitivity and specificity of 99m^Tc-YIGSR suggested it was a new promising tumor receptor radiotracer.