Bok B D, Scheffel U, Goldfarb H W, Burns H D, Lever S Z, Wong D F, Bice A, Wagner H N
Division of Nuclear Medicine and Radiation Health Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland.
Nucl Med Commun. 1987 Aug;8(8):631-41. doi: 10.1097/00006231-198708000-00004.
Several new lipophilic 99Tcm complexes have recently been described as alternatives to N-isopropyl (123I) iodoamphetamine (123IAMP) for measurement of regional cerebral blood flow (RCBF). In this study we have compared brain uptake and blood clearance of 99Tcm-N-ethylpiperidine-diamino dithiol (99Tcm-NEP DADT), its 4-methylated derivative (99Tcm-Me-NEP-DADT) and 99Tcm-hexamethyl-propylene-amine-oxime (99Tcm-HMPAO) with that of 123IAMP in two dogs. Single photon emission tomography (SPECT) was employed to measure brain accumulation and retention of the four radiopharmaceuticals. Cerebral uptake of the 99Tcm complexes (0.8-1.1%) was lower than that of 123IAMP (1.6% of the injected dose). There was considerable extracerebral activity in the dog's head, especially in the olfactory and snout regions. Because of slow blood clearance 99Tcm-HMPAO showed high uptake in these regions. Brain uptake of 99Tcm-HMPAO reached a plateau 5 to 10 min after intravenous injection and remained constant for the entire study period (1 h). 99Tcm-NEP-DADT, on the other hand, showed significant clearance from the brain after reaching maximal uptake at 10 to 15 min after injection. However, brain imaging with these agents was possible during the first 20 min. The mechanism of brain uptake, as well as the relationship between brain uptake and RCBF need to be evaluated for each of the four radiopharmaceuticals.
最近有几种新型亲脂性99锝配合物被描述为N-异丙基（123碘）碘安非他明（123IAMP）用于测量局部脑血流量（RCBF）的替代物。在本研究中，我们比较了99锝-N-乙基哌啶-二氨基二硫醇（99锝-NEP DADT）、其4-甲基化衍生物（99锝-Me-NEP-DADT）和99锝-六甲基丙烯胺肟（99锝-HMPAO）与123IAMP在两只狗体内的脑摄取和血液清除情况。采用单光子发射断层扫描（SPECT）来测量这四种放射性药物在脑中的蓄积和滞留情况。99锝配合物的脑摄取量（0.8-1.1%）低于123IAMP（注射剂量的1.6%）。狗头部存在大量脑外活性，尤其是在嗅觉和口鼻区域。由于血液清除缓慢，99锝-HMPAO在这些区域摄取较高。99锝-HMPAO的脑摄取在静脉注射后5至10分钟达到平台期，并在整个研究期间（1小时）保持恒定。另一方面，99锝-NEP-DADT在注射后10至15分钟达到最大摄取后，脑内有明显清除。然而，在最初20分钟内用这些药物进行脑显像是可行的。需要对这四种放射性药物中的每一种评估其脑摄取机制以及脑摄取与RCBF之间的关系。
