Breeman W A, de Jong M, Bernard B F, Bakker W H, Rolleman E J, Kwekkeboom D J, Visser T J, Krenning E P
Department of Nuclear Medicine, University Hospital Dijkzigt, Rotterdam, The Netherlands.
Nucl Med Biol. 1997 Nov;24(8):749-53. doi: 10.1016/s0969-8051(97)00122-4.
In patients undergoing somatostatin receptor scintigraphy, treatment with octreotide (Sandostatin) is usually discontinued 24-48 h before and after injection with the radioligand 111In-pentetreotide ([111In-DTPA(O)]octreotide) (Octreoscan) because octreotide competes with radioligand for the same receptors. However, Dörr et al. and Soresi et al. reported improved visualization of carcinoid and small cell lung cancer lesions, respectively, during continued octreotide treatment. We found that intravenous administration of unlabeled octreotide to rats inhibited the binding of an optimal dose (0.5 microg) of 111In-pentetreotide to somatostatin receptors in pancreas and adrenals in a mass- and time-dependent way. Pretreatment with unlabeled octreotide never increased receptor binding of 111In-pentetreotide. Administration of 100 microg of octreotide decreased receptor-bound radioactivity if given simultaneously with or 10 or 20 min after injection of the radioligand, but had no effect if given 30 min after the radioligand. These findings indicate rapid processing of receptor-bound octreotide and suggest that octreotide treatment of patients undergoing 111In-pentetreotide scintigraphy may be reinitiated as soon as 1 h after radioligand administration.
在接受生长抑素受体闪烁扫描的患者中，使用奥曲肽（善得定）治疗时，通常在注射放射性配体铟 - 111 喷曲肽（[铟 - 111 - DTPA（O）]奥曲肽）（奥曲肽扫描）前后 24 - 48 小时停药，因为奥曲肽与放射性配体竞争相同的受体。然而，多尔等人和索雷西等人分别报告称，在持续奥曲肽治疗期间，类癌和小细胞肺癌病灶的显像得到了改善。我们发现，给大鼠静脉注射未标记的奥曲肽会以剂量和时间依赖性方式抑制最佳剂量（0.5 微克）的铟 - 111 喷曲肽与胰腺和肾上腺中生长抑素受体的结合。用未标记的奥曲肽预处理从未增加铟 - 111 喷曲肽的受体结合。如果在注射放射性配体的同时或之后 10 或 20 分钟给予 100 微克奥曲肽，会降低受体结合的放射性，但在放射性配体注射后 30 分钟给予则没有效果。这些发现表明受体结合的奥曲肽处理迅速，并提示在接受铟 - 111 喷曲肽闪烁扫描的患者中，奥曲肽治疗可在放射性配体给药后 1 小时就重新开始。
