11C-methionine is used to study which process?

• A. Glucose metabolism
• B. Amino acid metabolism
• C. Fatty acid oxidation
• D. Oxygen consumption

Answer: (B)

11C-methionine is used to visualize amino acid metabolism because it is an actual building block for protein synthesis. When injected, the carbon-11 label lets PET imaging track how much methionine is transported into cells and incorporated into new proteins, reflecting the rate of amino acid uptake and protein production. This makes it particularly useful for highlighting tissues with high amino acid metabolism, such as certain tumors and active brain regions. It differs from tracers that measure glucose use, fatty acid oxidation, or oxygen consumption, which probe different metabolic pathways altogether.