POSITRON EMISSION TOMOGRAPHY STUDIES WITH C-11 ETHANOL IN INTRATUMORAL THERAPY FOR HEPATIC CELL-CARCINOMA

Positron emission tomography (PET) is a noninvasive functional method for the study of solid tumor perfusion, metabolism and interaction wit h different therapeutic agents. The aim of the study was the investiga tion of the metabolism of hepatocellular carcinomas (HCC) and the kine tics during a treatment with intratumoral ethanol by PET. The ongoing study includes seven patients with child A cirrhosis and HCC (UICC sta ge III-IVA; tumor size 3-6 cm), Dynamic PET studies (60 min) with F-18 -fluordeoxyglucose (FDG) were performed prior to therapy to assess tum or viability. The evaluation of the FDG data demonstrated a liver-equi valent uptake in six of the tumors (well and moderately differentiated HCC), which were poorly delineated against the normal liver parenchym a. One moderately differentiated HCC showed an increased FDG metabolis m, indicating no correlation between histology and metabolism. A dose of 37-80 MBq C-11-ethanol was applied together with a nonlabelled ther apeutic dose of the drug via a puncture needle positioned under sonogr aphy. Five out of seven tumors demonstrated a high C-11 uptake shortly after the end of the ethanol injection followed by constant C-11-etha nol concentration during the whole study period of 45 min. The PET dat a demonstrated no significant elimination of the C-11-ethanol from the tumor and no accumulation in the surrounding liver tissue. One case s howed a decrease of the intratumoral C-11-ethanol concentration due to a punkture of a tumor vein, and in another case the surrounding liver parenchyma demonstrated significant C-11 uptake in the early phase fo llowing paratumoral injection of the drug. In conclusion, PET is a use ful tool for the study of the mechanism and the kinetics of percutaneo us intratumoral ethanol injection of HCC.