FAP and neoplasm: In terms of semiquantitative analysis, no significant difference was observed regarding tumor uptake among the 3 radiotracers at 1 h after injection, whereas uptake of 68Ga-DOTA-4P(FAPI)4 was significantly higher than that of FAPI dimer (SUVmean, 1.99 ± 0.09 vs. 1.71 ± 0.10, P = 0.018) and monomer (1.20 ± 0.07, P < 0.001) in HT-1080-FAP tumors at 4 h after injection (Supplemental Fig. 5).