SLC38A4 and neoplasm: The TAC data (Fig. 2d) showed tracer uptake was significantly enhanced by 2.4-fold in tumor following injection of [18F]/[19F]-C-SNAT4 tracer at the ratio of 1: 200 (2.8 ± 0.2% ID/cc) compared to [18F]-C-SNAT4 only (1.2 ± 0.3% ID/cc) in 2 Gy-treated tumor-bearing mice.