^99Tc^m-精氨酸-谷氨酸-苏氨酸在荷人肺癌H1299裸鼠体内分布和显像

目的通过研究^99Tc^m-精氨酸-谷氨酸-苏氨酸（RET）在荷人肺癌H1299裸鼠体内的分布及显像，探讨其用于肺癌显像的可行性。方法采用^99Tc^m-直接法标记RET，再行^99Tc^m-RET与NSCLC细胞H1299的结合实验。荷人肺癌H1299裸鼠尾静脉注射^99Tc^m-RET后，行不同时间（15、30min，1、2．4、8、24、48h组各4只鼠）体内分布实验，分别测定组织放射性摄取（％ID／g）；另取荷瘤鼠3只，注射4．81MBq^99Tc^m-RET后于0．5、1、2、4．5、5、6h行γ显像。结果^99Tc^m-直接标记RET的标记率为（93．15±2．02）％，与H1299细胞的最高结合率为（3．56±0．37）％。荷瘤裸鼠尾静脉注射^99Tc^m-RET后4h肿瘤放射性摄取达（4．96±1．05）％ID／g，肝脏、脾脏有较多放射性摄取[（15．89±1．84）％ID／g和（10．83±1．66）％ID／g]；而心脏和血液的放射性摄取较少，相应的T／NT分别为5．70±0．21和12．40±0．11。注射^99Tc^m-RET后4．5～6．0h肿瘤显影清晰。结论^99Tc^m-RET具有亲肺癌的特性，有可能成为一种亲肺癌显像剂。

Biodistribution and gamma imaging of ^99Tc^m in human lung cancer xenografts

Objective To investigate the biodistribution and gamma imaging of ^99Tc^m-arginine-glutamate-threonine （RET） in nude mice bearing lung cancer xenografts and to explore its feasibility for human lung cancer imaging. Methods RET was labeled directly with ^99Tc^m. The binding efficiency of ^99Tc^m-RET with human NSCLC H1299 cells was measured. ^99Tc^m-RET was injected via the tail vein in nude mice bearing H1299 xenografts. The mice（n=32） were sacrificed at different time points： 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 24 h, and 48 h. Organs of interest were excised, weighted and counted by a gamma counter. The organ uptake was calculated as %ID/g. The gamma imaging was performed on 3 mice at 0.5, 1, 2, 4, 4.5, 5, 6 h after intravenous injection of 4.81 MBq ^99Tc^m-RET. Results The radiolabeling yield of ^99Tc^m-RET was （93.15±2.02）%, and the binding efficiency of ^99Tc^m-RET with H1299 cells was （3.56±0.37）%. At 4 h after injection, the uptake of tumor, liver and spleen was （4.96±.05） %ID/g, （15.89±1.84） %ID/g and （ 10. 83±1.66） %ID/g and the T/NT was 5.70±0.21 for the heart and 12.40±0.11 for the blood. The tumor in nude mice could be best visualized at 4.5-6.0 h. Conclusion ^99Tc^m-RET might have potential to serve as a lung cancer imaging agent.