Inclusion Criteria:  2017 AJCC renal cell carcinoma TNM stage III, IV lesions; In contrast-enhanced CT staging, suspicious metastases were found; There were no known peripheral or central venous problems; 68Ga PSMA PET / CT imaging can be performed within 6 weeks after the diagnosis of renal cell carcinoma; Signed the informed consent form of voluntary participation in clinical trials.  Exclusion Criteria:  Age ≤ 18 years old; Can't stand lying flat in PET / CT examination; There are contraindications for 68Ga PSMA ligands; In the past two years, there was a history of other malignant tumors, or according to the doctor's research judgment, complications may occur and affect the normal operation of the test; Renal function is impaired or hemodialysis is in progress.