Fig. 2.
Time-dependent uptake of FET, [18F]1 and its derivatives, FET-Gly ([18F]2), FET-Ala ([18F]3) and AcFET ([18F]4), in 9L glioma cells were measured. They are expressed as percentage of uptake in 100 μg protein (mean ± SD, n = 3). The cell uptake for FET, [18F]1, was much higher than its derivatives. It is likely that the amino acid transporter on the tumor cell surface would only recognize the FET, [18F]1; while all of the derivatives displayed low cell uptake.