FAP and neoplasm: Contrastingly, sharp and rapid uptake of [68Ga]Ga-DOTA-FD1 was observed at the tumor site of HT1080-FAP models, as depicted in Fig. 2A. The quantitative tumor uptake revealed by ROI analysis (8.85 ± 3.30%ID/g, n = 4; Fig. 2B) and biodistribution study (19.20 ± 6.51%ID/g, n = 3; Fig. 2C) was significantly greater than that in other tumor types (ROI: P < 0.01 in BxPC-3 and Panc-2 models, P < 0.05 in HT-1080 models; biodistribution: P < 0.01 in all the 3 models).