Gamma counting of harvested organs and tumors 1 h and 3 h after injection of 68Ga-OncoFAP demonstrated strong, specific, and temporally stable accumulation in FAP+ tumors with increasing contrast due to fast washout from blood (FAP+ tumor-to-blood ratio 1 h p.i.: 8.6 ± 5.1 (n = 6), 3 h p.i.: 38.1 ± 33.1 (n = 6); ratio FAP+ tumor/FAP− tumor 1 h p.i.: 9.5 ± 5.6, 3 h p.i.: 25.3 ± 19.2). This evidence concerns the gene FAP and neoplasm.