Purpose: The distribution characteristics of 18F- fluoromethylcholine ( 18F-choline) in tumor and inflammatory tissue were compared with those of 14C or 3H-2-deoxyglucose (2DG) as a substitute for fluorodeoxyglucose (FDG). Methods: A solid tumor model of AH109A in the back of Donryu rats and an aseptic inflammation model of turpentine oil injection subcutaneously in rats were used for experiments. Tissue distribution was examined at 5, 30 and 60 min after injection of a mixture of 18F-choline and 3H-2DG. Double-tracer high-resolution autoradiographs (ARGs) of tumor and inflammation were obtained using 18F-choline and 14C-2DG. Whole body (WB) ARG was performed with 18F-choline. Results: Tumor uptake of 18F-choline reached a peak at 30 min, when the tumor to blood ratio was 5.1. Both tumor and inflammation uptake of 2DG were higher than those of 18F-choline. 18F-choline uptake by inflammation was lower than that by tumor. The tumor to brain uptake ratio was 5.7 with 18F-choline and 1.2 with 2DG. In the ARG of inflammation, linear or ring-like structures of 2DG uptake were observed in the wall of the abscess, but were not identified with 18F-choline. Photomicrography showed that the uptake was limited to granulocytes, macrophages and fibroblasts, consistent with sub-acute or chronic inflammation. Conclusion: 18F-choline uptake by inflammation was lower than that of 2DG in the tissue distribution study, and 18F-choline uptake by abscess wall was significantly lower than that of 2DG in the autoradiography study. Our results may suggest the feasibility of 18F-choline-PET imaging for the differential diagnosis of cancer and chronic inflammation in lung and brain.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging