【作者】 宋进华；

【导师】 刘璐；

【作者基本信息】 东南大学 ， 影像医学与核医学， 2005， 硕士

【摘要】 研究目的1.建立¹⁸⁸Re标记小剂量奥曲肽（octreotide, OCT）的方法学;2.观察¹⁸⁸Re-OCT在正常小鼠体内的生物学分布;3.建立BALB/c裸鼠荷人H460非小细胞肺癌移植瘤动物模型;4.观察¹⁸⁸Re-OCT在荷瘤裸鼠体内的生物学分布。研究方法SnCl2·2H2O的用量为50至1600μg,OCT的用量为10、20或30μg,乙酸缓冲液的pH值从4.0至6.0,反应体系的温度为室温、60、80或100℃,淋洗液体积从0.05至0.20ml,分别改变标记条件中的某一项条件,测定标记物的标记率及其在体外的稳定性,建立最佳的标记方法。将适量标记物分别经正常小鼠和荷瘤裸鼠尾静脉注射,于注射后不同时间点取血液、肿瘤组织及主要脏器测量其放射性计数率值,经放射性衰变校正后计算每克组织的百分注射剂量率（%ID/g）,观察标记物在动物体内的生物学分布。其中每个时间点取一只动物处死前行SPECT显像,在荷瘤裸鼠显像时利用感兴趣区技术对T/N（肿瘤/正常组织）比值进行半定量分析。两只裸鼠瘤体内直接注射给药,分别给药后多个时间点行SPECT显像,与尾静脉给药组进行对照。研究结果¹⁸⁸Re直接法标记小剂量奥曲肽的最佳条件:葡庚糖酸钠（0.3mmol/L）0.1mL,SnCl2·2H2O（16g/L）0.05ml,乙酸缓冲液（pH=5）0.1ml,奥曲肽（0.1g/L） 0.1mL,通氮气震荡反应1h,再加入新鲜¹⁸⁸Re淋洗液0.1ml,100℃水浴30min,¹⁸⁸Re-OCT标记率可达到（95.3±1.8）%,室温下放置24h放化纯为（89.6±2.5）%。¹⁸⁸Re-OCT在正常小鼠体内主要分布于肝脏、肾脏及肠道,¹⁸⁸Re-OCT在荷瘤裸鼠体内主要分布于肿瘤组织、肝脏、肾脏及肠道,肿瘤部位在4h摄取达到高峰,此时SPECT显像在肿瘤部位有明显的放射性核素浓聚,（肿瘤/肌肉组织）比值在注射后24h达到高值为7.1。瘤体内直接注射给药具有更高的T/N比值。结论研究建立的¹⁸⁸Re标记OCT方法操作简便,反应时间短,标记率高,体外稳定性好,无需进一步纯化,奥曲肽用量较小,预期能提高靶向定位质量,¹⁸⁸Re-OCT在正常小鼠体内主要被肠道、肝脏、肾脏等器官摄取,血液清除快。¹⁸⁸Re-OCT在荷瘤裸鼠体内对人非小细胞肺癌具有靶向定位作用,其在肿瘤部位的分布具有较高的T/N比值,¹⁸⁸Re-OCT有望用于表达生长抑素受体肿瘤的核素靶向治疗。经皮穿刺瘤体内给药可以大大提高T/N比值,临床使用可能减少正常组织和器官的不必要的损伤。更多还原

【Abstract】 Objective To study a method for labeling a low dosage of octreotide with rhenium-188 and building a nude mice mode which bearing H460 none small cell lung cancer. To study the biodistribution of ¹⁸⁸Re-octreotide in normal mice and nude mice. Methods The amount of stannous chloride changed from 50 to 1600μg, octreotide was 10,20 or 30μg, pH value of acetate buffer from 4.0 to 6.0, the volume of rhenium-188 perrhenate from 0.05 to 0.20ml, the reaction temperature from room temperature to 100℃. The labeling efficiency and the in vitro stability of ¹⁸⁸Re-octreotide were analyzed.Those normal mice were been killed and the blood,major organs were taken out from those mice at 0.5h, 1h, 2h, 4h, 24h after been injected ¹⁸⁸Re-octreotide through the tail veins, and one normal mouse have been randomized allocated from each term for SPECT scanning before those mouse were killed, then the radioactivity count of those organs were measured. Similarly,four nude mice had SPECT scaned at 2h, 4h, 24h,48h after injection, and using ROI technique for semi-quantitative analysis of main organ and tumor uptake. Others nude mice were killed at 2h, 4h, 24h,48h after injection,then tumors and major organs were taken out and the radioactivity count of those organs and tumors were measured. Two nude mice SPECT scaned after intratumor injected ¹⁸⁸Re-octreotide and the tumor/organ ratios were studied. Results The optimal conditions for rhenium-188 labeling reaction are follows: 0.1ml sodium glucoheptonate（0.3mmol/L）,0.05ml stannous chloride（16g/L）was dissolved by 0.1mol/ L hydrochloric ,0.1ml acetate buffer （pH=5）and 0.1ml octreotide （0.1g/L）were mixed at room temperature for 1h with nitrogen atmosphere and continuous agitating. 0.1ml fresh rhenium-188 perrhenate was added, water bathing 100℃for 30min. It was found that the labeling efficiency of ¹⁸⁸Re-octreotide was （95.3±1.8）%, after it was cooled in room temperature, radiochemical purity was （89.6±2.5）% at 24h. ¹⁸⁸Re- octreotide was major distributed in lives, small bowels, large bowels and kidneys in normal mice, and major distributed in tumors,lives, small bowels, large bowels and kidneys in nude mice.The largest uptake of tumors is 9.8%ID/g at 4h after injection.The largest tumor/muscle ratios in the SPECT study in those nude mice is 7.1 at 24h after injection. Those nude mice of intratumor injected have higher tumor/organ ratios than tail vein injected ones. Conclusion This method of labeling octreotide with rhenium-188 is convenient with satisfactory in vitro stability and labeling efficiency, and does not need further purification to the labeling radiopharmaceutical before administration. The distribution of radionuclide will been reduced in the non-target organs because of the low dosage of octreotide. The clear of ¹⁸⁸Re-octreotide from blood is fast, ¹⁸⁸Re-octreotide was up taken highly by small and large bowels followed by kidneys and livers. the tumor/muscle ratios in nude mice is large enough for targeting therapy. The tumor/organ ratios have been raised through intratumor injected.更多还原