Ercan M T, Durak H S, Kitapçi M, Caner B E, Senekowitsch R
Department of Nuclear Medicine, Hacettepe University Medical Faculty, Ankara, Turkey.
Nuklearmedizin. 1991 Feb;30(1):35-9.
Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 +/- 9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 +/- 6.3% as determined by TCA precipitation. Blood clearance of 99mTc-K4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 +/- 0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection. 99mTc-K4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.
维生素K4用99mTc标记，标记效率高于97%。该化合物在室温下24小时内稳定，其在NMRI小鼠体内的生物分布表明了其体内稳定性。血液放射性水平在很宽的范围内都很高。注射后24小时，10%的注入活性仍留在血液中。排泄主要通过肾脏。只有肝脏和肾脏聚集了相当数量的放射性。睾丸/软组织比值在6小时和24小时分别为1.4和1.57。睾丸/血液比值低于1。对小鼠血液的体外研究表明，33.9±9.6%的放射性与红细胞相关；用生理盐水几乎可将其完全洗脱。通过三氯乙酸沉淀法测定，蛋白质结合率为28.7±6.3%。正常受试者体内99mTc-K4的血液清除显示放射性缓慢下降，16小时后达到平台期，为注入活性的20%。在男性的闪烁扫描图像中，睾丸可以清晰显示。右/左睾丸比值为1.08±0.13。睾丸/软组织和睾丸/血液活性比值在3小时时最高。这些比值高于注射后20分钟用高锝酸盐获得的比值。99mTc-K4似乎是一种有前景的用于睾丸闪烁显像的放射性药物。
