Abstract
1345
Objectives: Malignant transformation increases glycolysis but also often increases amino acid metabolism; therefore we evaluated the biodistribution of eight amino acids and FDG in a rodent model of breast cancer to determine their potential as imaging agents.
Methods: Tritiated L-methionine, valine, threonine, isoleucine, arginine, tyrosine, serine and lysine were co-injected intravenously with 18F-FDG into groups of female Lewis rats bearing rat mammary tumors. After sixty minutes, rats were sacrificed, tissues harvested, amino acid uptake measured and compared to 18F-FDG.
Results: FDG had significantly greater tumor uptakes values than amino acid tracers with the exception of methionine, arginine, and threonine. In areas of high physiological FDG uptake such as the brain and heart, several amino acids provided significantly superior tumor-tissue ratios than did FDG: lysine, threonine, tyrosine, valine, methionine, and arginine.
Conclusions: These experiments support several radiolabeled amino acids as promising tracers in areas of problematic FDG uptake.
- Society of Nuclear Medicine, Inc.