In this study, we quantified the tumor uptake of [18F]AlF-NOTA-FAPI-04 on PET/CT for different pathological types of lung cancer and metastatic tumors to characterize FAP expression in lung cancer and to explore the ability of [18F]AlF-NOTA-FAPI-04 PET/CT to distinguish different types of lung cancer. The gene discussed is FAP; the disease is lung carcinoma.