O-[18F] fluoromethyl-L-tyrosine for differentiation between tumor and inflammation

O-[F-18]fluoromethyl-L-tyrosine (F-18-FMT) is a recently developed tumor-detecting agent with simple preparation and high radiochemical yields. The aim of this study was to evaluate the potency of F-18-FMT for differentiating tumor and inflammatory tissues using an animal model. An ascites hepatoma cell line, AH109A, turpentine oil and Staphylococcus aureus were inoculated subcutaneously into Donryu rats for a tumor model, aseptic inflammation model and bacterial infection model, respectively. The biodistribution of radioactivity was assessed in rats after injection with F-18-FMT. Dual tracer whole-body autoradiography was performed with a mixture of F-18-FMT and 2deoxy-D-[1 -C-14] glucose (C-14-DG). Tumor uptake of F-18-FMT at 30 min and 60 min were significantly higher than that in other normal tissues, except pancreas. The uptakes in the aseptic and bacterial inflammatory tissues were very small and were not different from the background tissues. Dual tracer whole-body autoradiographic study showed that tumor uptake of F-18-FMT was clearly higher than the other tissues, while F-18-FMT accumulated much less both in aseptic and bacterial inflammatory tissues. In conclusion, F-18-FMT seems a favorable tracer for the differentiation between tumor and inflammation because of higher specificity to tumor.