核素标记血管多肽显像诊断恶性肿瘤实验研究

目的]以肿瘤血管系统为目的靶，以核素标记多肽ATWLPPR为显像剂，探讨核素标记肿瘤血管特异性多肽显像用于肿瘤诊断的可行性。方法]应用^99mTc标记ATWLPPR并鉴定。制作荷人乳腺癌裸鼠模型，实验组于注射^99mTc-ATWLPPR后不同时间显像，对照组应用未标记ATWLPPR预处理后显像，勾画感兴趣区，计算两组肿瘤与对侧相应部位放射性比值。荷瘤裸鼠于注射显像剂后180min，取感兴趣器官及肿瘤组织称重并测量放射性计数。结果]以HYNIC作为双功能螯合剂，^99mTc-HYNIC—ATWLPPR标记率可达91．53％±2．39％，放化纯为94．14％±1．75％，标志物体外稳定。实验组荷瘤裸鼠注射显像剂后180min肿瘤部位显影最为清晰，对照组肿瘤部位未见明显显像剂分布，两组肿瘤／对侧上肢的放射性比值分别为2．33±0．40和1．18±0．12（P〈0．05）。显像剂在荷乳腺癌裸鼠体内肝脏和肾脏的摄取最高，脑部摄取最低。结论]制备的^99Tc-HYNIC-ATWLPPR方法简单，标记率和放化纯高、稳定性好，主要以肝脏和肾脏排泄，肿瘤组织可以对该品像剂特异忡格取辊示该显像剂可以用于肿瘤诊断．

An Experimental Study on Radionuclide Imaging with Radiolabeled Blood Vessel Polypeptide in Diagnosis for Malignant Tumor

Purpose] To explore the possibility of radiolabeled tumor blood vessel specific polypeptide imaging in diagnosis for tumor with tumor blood vascular system as the target and radiolabeled ATWLPPR as the agent. Methods] ^99mTc-HYNIC-ATWLPPR was prepared and identified. Human breast cancer-bearing nude mice model was cultured. The images （experimental group） carried out after injected ^99mTc-ATWLPPR at different time and the images （control group） carried out after pretreated with non-radiolabeled ATWLPPR. Regions of interest （ROI） were drawn and the radioactivity ratios of T/NT （tumor and opposite relevant region） were calculated in two groups. Organs of interest and tumor tissue in tumor-bearing nude mice were weighed. Radioactivity counts in different tissue were measured after injection of the agent 180min later. Results] ^99mTc- HYNIC-ATWLPPR was prepared with HYNIC as bifunctional chelating agent with labeling efficiency as 91.53%±2.39% and radiochemical purity as 94.14%±4.25%. The agent was stable in vitro. Images showed that tumors were clearly seen after injection of agent 180min later in experimental group, but no tracer could be found in tumors of control group. The radioactivity ratio of tumor/opposite upper limb site were 2.33±0.40 and 1.18±0.12, respectively （P〈0.05）. The biodistribution of agent in breast cancer-bearing nude mice showed the most tracer accumulated in the liver and kidney, but the least in the brain. Conclusions] The labeling method used in preparing ^99mTc-HYNIC-ATWLPPR is simple and the agent has high radiolabeling yield, radiochemical purity and good stability. The agent is mainly excreted through liver and kidney. Tumor could uptake the agent specifically and the agent could be applied in diagnosis for tumor.