To study the normal physiological distribution of the probe 124I-EV in human body and its ability to detect overexpression of Nectin-4 in tumor lesions.

Nectin-4 is highly expressed in different types of cancer and is involved in various aspects of tumor proliferation, angiogenesis, metastasis, tumor recurrence, and DNA repair. Therefore, the development of nuclear medicine molecular probes targeting Nectin-4 is of great significance for improving the specificity and accuracy of Nectin-4 related cancer diagnosis.

EV (Enfortumab vedotin) is the first and only drug targeting Nectin-4 so far. By exploring the diagnostic efficacy of 124I-EV in tumors with high nectin-4 expression, it will not only provide evidence for the early diagnosis of tumors. At the same time, the Nectin-4 expression in tumors can be used to develop effective and precise treatment for patients.

Inclusion Criteria:

1. 18-75 years old, male or female;
2. Patients recommended by clinicians to undergo PET/CT examination for tumor diagnostic staging;
3. The subject patients could fully understand and voluntarily participate in the experiment, and signed the informed consent.
4. Normal heart function;
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 the start of 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.

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.