The AUC value of mixture tracer [18F]/[19F]-C-SNAT4 (ratio at 1: 200) uptake in treated tumor (Fig. 2f) was 242.0 ± 17.2% ID min/cc, which was higher than the AUC value of [18F]-C-SNAT4 in treated (123.6 ± 30.9% ID min/cc) and untreated tumors (92.1 ± 20.9% ID min/cc) (P < 0.0001; n = 4). Here, SLC38A4 is linked to neoplasm.