FAP and neoplasm: The uptake of 177Lu-DOTAGA-FAPI-FUSCC-I and 177Lu-DOTAGA-FAPI-FUSCC-II showed a significant trend of decreasing radioactivity in HT-1080-FAP tumors at 24 h, and both radiopharmaceuticals exhibited similar tumor uptake from 1 h to 24 h, with an in-tumor retention of approximately 20% at 24 h.