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体^ F标记的氟化脱氧半乳糖（FDGal）的潜在用途<18>。本工作的目的是阐明其在临床医学中的诊断价值。动物实验集中于示踪剂在哺乳动物中的行为及其放射性和非放射性形式的毒性。发现FDGal几乎完全集中在肝脏中，因此我们将非癌症患者可摄入人体的最大活性限制为低至2 mCi。在确认了非放射性形态的示踪剂的最小毒性后，按照东北大学临床PET委员会的指导方针开始了临床应用。不出所料，在人体肝脏中发现了示踪剂的选择性蓄积，肝硬化患者的摄取减少。后者的摄取率约为正常人的2/3。然而，由于我们不能测量门静脉中的活性浓度，因此我们未能建立严格意义上的肝脏半乳糖代谢的定量。另一个新的发现是我们发现示踪剂在肝细胞癌中的高积累。部分患者骨和眼眶内肝癌转移灶清晰可见。因此，我们在此提出了一种新的和确定性的诊断方法，即利用<18><18>已知的恶性肿瘤诊断剂之一的~ 13 F-脱氧葡萄糖（~ 13 F-脱氧葡萄糖）和~ 13 F-标记的FDGal诊断肝癌。原发性肝癌同时含有两种示踪剂，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.