99Tc^m-HYNIC-Octreotide的标记及其在脑膜瘤诊断中的初步应用

目的：建立99Tcm标记HYNIC-Octreotide的最佳方法,评价该显像剂用于临床的可能性。方法：以SnCl2为还原剂,按间接法标记99Tc^m-HYNIC-Octreotide。观察标记物的体内、体外稳定性。对6只实验用大耳白兔、3名健康志愿者及3名后来经病理证实的脑膜瘤患者初步进行了生长抑素受体显像。结果：99Tc^m-HYNIC-Octreotide的标记率为97.8%±0.55%。99Tc^m-HYNIC-Octreotide的体内、体外稳定性：①静置稳定性：静置4h标记率仍达90%以上。②半胱氨酸置换试验：游离99Tcm随半胱氨酸的增加而缓慢上升,当半胱氨酸达200mmol/L时,99Tc^m-HYNIC-Octreotide分子中约23%的99Tc^m的被置换出。③血清结合试验：24h99Tcm-HYNIC-Octreotide与蛋白结合率为17.04%±0.01%。99Tc^m-HYNIC-Octreotide显像结果：①正常兔及正常人99Tcm-HYNIC-Octreotide体内分布特点：膀胱和肾脏最浓,其次是肝脏,鼻黏膜轻度浓聚,颅脑、双肺、肠道内未见明显核素浓聚。②3名脑膜瘤患者放射性核素明显浓聚,注射显像剂4h后肿瘤放射性计数与本底放射性计数的比值（T/NT）为5.36。结论：99Tc^m标记HYNIC-Octreotide方法可行,标记率和放化纯高,稳定性好。初步临床显像证明99Tc^m-HYNIC-Octreotide是一种具有潜力的诊断脑膜瘤的生长抑素受体显像剂。

Preliminary clinical application of HYNIC-Octreotide labeled with 99Tcm in the diagnosis of meningioma

Objective： To develop a method to label HYNIC-Octreotide with 99Tc^cm indirectly and evaluate its potential as a clinical imaging agent. Methods： SnCl2 as a reducing agent was adopted to label HYNIC-Octreotide with 99Tc^m indirectly, to observe the stability of the labeled drugs; 6 rabbits, 3 healthy volunteers and 3 patients with meningioma were examined by this somatostatin receptor agent. Results： The label rate of 99Tc^m-HYNIC-Octreotide was 97.8%±0.55%. The stability of the labeled drugs： ①The stability after 4 hours were above 90%. ②The replace test of cysteine： with the increase of cysteine, free 99Tc^m was found to raise slowly, about 23% free 99Tc^mwas break away from 99Tc^m-HYNIC-Octreotide when the concentration of cysteine was up to 200mmol/L. ③Plasma binding： the rate of 99Tc^m-HYNIC-Octreotide combined with plasma is 17.04%±0.01% for 24 hours. ①Character of distribution with the radionuclide drug in rabbits and volunteers： Intense uptake was found in bladder and kidney, moderate uptake in liver, mild uptake in mucous membrane of nose, no obvious uptake in brain, lung and intestinal tract.②Intense uptake was found in 3 patients with meningioma, the average value of T/NT was 5.36 after 4 hours. Conclusions： This method to label HYNIC-Octreotide with 99Tc^m is promising; it has a high label rate and stability. 99Tc^m-HYNIC-Octreotide has a potential as an agent imaging to meningioma.