Breeman W A, Kwekkeboom D J, Kooij P P, Bakker W H, Hofland L J, Visser T J, Ensing G J, Lamberts S W, Krenning E P
Department of Nuclear Medicine, University Hospital Dijkzigt, Rotterdam, The Netherlands.
J Nucl Med. 1995 Apr;36(4):623-7.
To increase the target-to-background ratio in receptor scintigraphy, we hypothesized that receptor scintigraphy is best performed using the lowest possible mass with the highest possible specific radioactivity of the radioligand.
Rats were injected with 2 or 10 micrograms of unlabeled octreotide or 2 or 10 micrograms of 111In-pentetreotide. Scintigraphic images were then obtained from 10 min before to 20 min after the 111In injection.
In some instances, there was a significant increase in 111In uptake in somatostatin receptor-positive organs. In others, there was a significant decrease. Since no significant differences were found in background radioactivity in the percent dose uptake of 111In in receptor-negative organs, these data indicate that target-to-background ratios can be increased by the administration of nonradiolabeled peptides under select conditions.
The uptake of 111In-pentetreotide in somatostatin receptor-positive organs results in a tissue-specific bell-shaped function of the injected mass of the radiopharmaceutical. This curve may also apply to somatostatin receptor-positive tumors, the visualization of which may be enhanced by optimizing the mass of 111In-pentetreotide.
为提高受体闪烁扫描术中的靶本底比，我们假设受体闪烁扫描术在使用放射性配体尽可能低的质量和尽可能高的比放射性时效果最佳。
给大鼠注射2或10微克未标记的奥曲肽或2或10微克111铟-喷替肽。然后在注射111铟前10分钟至注射后20分钟获取闪烁扫描图像。
在某些情况下，生长抑素受体阳性器官中111铟的摄取显著增加。在其他情况下，则显著减少。由于在受体阴性器官中111铟的剂量摄取百分比的本底放射性未发现显著差异，这些数据表明在特定条件下给予非放射性标记肽可提高靶本底比。
111铟-喷替肽在生长抑素受体阳性器官中的摄取导致放射性药物注射质量的组织特异性钟形函数。该曲线也可能适用于生长抑素受体阳性肿瘤，通过优化111铟-喷替肽的质量可增强其可视化效果。
