摘要：
目的:制备99Tcm标记MAG3-isoDGR-2C小分子多肽,探讨 其作为ανβ3靶向新型分子显像剂的可能性.方法:利用葡庚糖酸盐(Glucoheptonate,GH)转换络合法进行99Tcm对MAG3-isoDGR-2C的标记;将S180荷瘤鼠采用随机抽样法分为5组,每组5只,分别于注射99Tcm-MAG3-isoDGR-2C 30 min,60 min,120 min,240 min和360 min后断头处死,计算各脏器放射性摄取(％ID/g)、肿瘤/血液(T/B)和肿瘤/肌肉(T/M)摄取比值.取荷瘤鼠5只,在注射后不同时间点分别进行SPECT显像,并利用勾画感兴趣区技术计算T/NT的比值.结果:利用转换络合法能够成功的进行标记99Tcm-MAG3-isoDGR-2C,放射化学纯度能够达到94.34％,放射性比浓度10.93 MBq/mL且无需纯化;荷瘤鼠体内分布显示该标记物能够较快的从血液中清除,主要经肾脏排泄,心脏、肺、脾脏、胃、骨骼等组织的放射性摄取均很少,而肿瘤组织具有一定的放射性摄取,在4h T/B和T/M摄取比值分别为1.75和10.50;注射99Tcm-MAG3-isoDGR-2C后2 h SPECT显像可见肿瘤组织显影最清晰,T/NT比值为3.24± 1.71.结论:99Tcm-MAG3-isoDGR-2C标记方法简便、易行、标记率高,对恶性肿瘤具有一定的靶向性,有潜力成为一种新的分子显像剂.%Objective:To study the feasibility of using labeled MAG3-isoDGR-2C with 99Tcm as a potential molecular imaging agent for ανβ3 targeting.Method:The MAG3-isoDGR-2C was labeled with 99Tcm using glucoheptonate transformation and complexation.S180 tumor bearing mice were divided into 5 groups with 5 mice each.At 30 min,60 min,120 min,240 min and 360 min after the injection of 99Fcm-MAG3-isoDGR-2C,the mice were sacrificed by decapitating.The biodistribution in the organs,T/B and T/M was calculated.SPECT imaging was performed at different time points after injection in 5 tumor bearing mice,and the ratio of T/NT were calculated by using ROI.Results:The MAG3-isoDGR-2C was labeled with 99Tcm effectively and simply,and the radiation chemical purity could reach to 94.34％ without purification.The biodistribution showed the tracer was cleared rapidly from blood and was mainly excreted through kidney.The radioactive uptake in heart,lung,spleen,stomach and bone was low,and the uptake in tumor could be visualized.The maximum ratios of T/B and T/NT were 1.75 and 10.50 respectively in the time of 4 hours after injection of the tracers.The SPECT images demonstrated the increased activity in the region of tumor with the maximum T/NT of 3.24±1.71.Conclusion:99Tcm-MAG3-isoDGR-2C can be made easily and show certain targeting ability to the malignant process,which proves its potentiality to become a new molecular imaging agent.
