DOTA.SA.FAPi TFA inhibits fibroblast activation protein ( FAP ) with an IC 50 of 0.9 nM. DOTA.SA.FAPi TFA targets protease PREP with an IC 50 of 5.4 μM. DOTA.SA.FAPi TFA can be used a PET tracer, when labeled with 68 Ga, and used for research about cancer. DOTA.SA.FAPi (TFA) can be used for the synthesis/research of Radionuclide-Drug Conjugates (RDCs).