SLC1A5 and central nervous system cancer: In distinction to other amino acid PET tracers, such as L-[methyl-11C]-methionine (MET), 18F fluoro-ethyltyrosine fluoroethyltyrosine (FET), and 3,4-dihydroxy-6-[18F] fluoro-L-phenylalanine (FDOPA) which are predominantly transported via system L amino acid transporters, fluciclovine undergoes cellular transport by both system L and system alanine-serine-cysteine (ASC), specifically ASCT2, in human astrocytes and glioma cells [11].