QUANTITATIVE REGIONAL MAPPING OF LIVER FUNCTION USING FLUORINATED POSITRON EMITTERS AND POSITRON EMISSION TOMOGRAPHY

我们已经报道了用正电子发射器标记的氟化脱氧半乳糖（FDGal）的潜在用途，^<18>F。本研究的目的是阐明其在临床医学中的诊断作用。动物实验主要集中在示踪剂在哺乳动物中的行为及其以双放射性和非放射性形式存在的毒性。我们发现FDGal几乎只集中在肝脏中，因此我们限制了非癌症患者可摄入的最大活性低至2 mCi。在非放射性形式的示踪剂的最小毒性检查后，我们按照东北大学临床PET委员会的指导开始了临床应用。正如预期的那样，我们发现示踪剂在人类肝脏中选择性积累，并且在肝硬化患者中摄取减少。后者的摄取率接近正常人的2/3。然而，由于我们无法测量门静脉的活性浓度，我们未能严格定量肝脏半乳糖代谢。另一项新发现是，我们发现示踪剂在肝细胞癌本身高度积累。在一些患者中可以清楚地看到骨和眼眶的肝癌转移灶。因此，我们在此提出了一种新的有效的诊断方法，使用^<18> f标记的FDGal和FDG （^<18> f -脱氧葡萄糖），这是已知的恶性肿瘤的诊断试剂之一。原发性肝癌同时使用两种示踪剂，而转移性肝肿瘤仅使用FDG。

We already reported the potential usefulness of fluorinated deoxygalactose (FDGal) labelled with a positron emitter, ^<18>F. The aim of the present work was to clarify its diagnositic usefulness in clincal medicine. Animal expeimetns has been concentrated into the behavior of the tracer in mammals and its toxity in botradioactive and nonradioactive forms. FDGal was found to concentrate almost exclusively in the liver and for that we limited the maximaum activity ingectable to humans as low as 2 mCi for non-cancer patients. After the check of minimum toxity of the tracer in nonradioactive form, we started its clinical application following the guides of the Clincal PET Committee of Tohoku University.As expected, we found selective accumulation of the tracer in the human liver and decreaed uptake in case of liver cirrhosis patients. The uptake ratio in the latter was nearly 2/3 of normals. However, we failed to develope quantitation of liver galactose metabolism in strict sence as we icould not measure activity concentration in the portal vein. Another new finding was htat we found high accumulation of the tracer in the hepatocellular carcinoma itself. Metastatic lesions from hepatoma in bone and the orbit were clearly visualized in some patients. Thus we here propose a new and befinitive diagnostic method of thpatocellular carcinoma using ^<18>F-labelled FDGal and FDG (^<18>F-deoxyglucose) that is one of known diagnostic agents for malignant neoplasmas. Primary hepatomas incorporate both two tracers while metastatic liver tumors take FDG only.