To evaluate the ability of [68Ga]N188 to detect nectin-4 overexpression in patients with urothelial carcinoma, especially in patients with recurrent or advanced bladder cancer.

Inclusion Criteria:

1. 18-75 years old, male or female;
2. Heart function is normal;
3. Normal heart function;
4. Estimated survival ≥12 weeks;
5. Good follow-up compliance;
6. presence of at least one measurable target lesion according to RECIST1.1 criteria;
7. Women of childbearing age (15-49 years) must have a negative pregnancy test within 7 days before starting the test; Fertile men and women must agree to use effective contraception to prevent pregnancy during the study period and for 3 months after the test;
8. Patients recommended by clinicians to undergo PET/CT examination for tumor diagnostic staging;
9. The subject patients could fully understand and voluntarily participate in the experiment, and signed the informed consent.

Exclusion Criteria:

1. Serious abnormality of liver, kidney and blood;
2. Pregnant patients;
3. Pregnant and lactation women;

3) unable to lie flat for half an hour; 4) Refuse to join the clinical investigator; 5) Suffering from claustrophobia or other mental diseases; 6) Other conditions that researchers deem unsuitable for participating in the experiment.