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.