Comparison of 2- and 3-18F-fluoro-deoxy-D-glucose for studies of tissue metabolism

2- and 3-18F-fluoro-deoxy-D-glucose were proposed as sugar analogs to study glucose metabolism in brain and heart tissues. To evaluate their usefulness, the in vivo behavior of 2- 28FDG and 3-18FDG was investigated in mice and rats and for 3-18FDG in dogs at various times post-injection. Positron emission tomographic (PET) imaging was performed for heart and brain of anesthetized dogs with both radiopharmaceuticals. In all species studied, a higher uptake in brain, heart and kidney was observed for 2-18FDG compared with 3-18FDG. Radioactivity also cleared blood and liver more rapidly with 2-18FDG than with 3-18FDG. Estimates of brain kinetic model parameters revealed the metabolic trapping of 2-18FDG, making this agent favorable for studies of tissue metabolism, and the relative lack of phosphorylation of 3-18FDG, which makes it a potential agent for studies of glucose transport.