ALB and neoplasm: The highest tumor uptake of PSMA-NARI-56 (40.56 ± 10.01%ID/g) was observed after 48 h, and the tumor uptake of PSMA-NARI-56 was also 2.4-fold higher than that of PSMA-617 after 72 h, which confirms the effect of higher plasma protein (albumin) binding on PSMA-expressing tissue uptake.