Clinical Application of PET Imaging Targeting Nectin-4 in Malignant Tumors

To perform integrated PET/MR or PET/CT visualization of patients with clinically suspected or confirmed urothelial carcinoma, breast cancer, lung carcinoma and other malignant tumors with high Nectin-4 expression and healthy volunteers, using specific positron imaging agents targeting Nectin-4 (taking \[68Ga\]Ga-NOTA-Nectin-4 antibody fragment as an example), to achieve the following purposes: Patients with malignant tumors: for diagnosis and staging of diseases, comparing with the gold standard pathological diagnosis, evaluating diagnostic efficacy, clarifying the presence or absence of lesions, and determining the location and nature of lesions; comparing with \[18F\]FDG PET for accurate staging, evaluating the tumor load, and helping to determine the therapeutic plan. Healthy volunteers: Pharmacokinetic analysis will be performed to clarify the distribution and metabolism of the drug in the body and its safety.