This study investigates PET imaging in malignant tumors with high Claudin18.2 (CLDN18.2) expression. The purpose of this study is to explore the application of PET/MR or PET/CT imaging in patients with gastric cancer, pancreatic cancer, cholangiocarcinoma, or other malignant tumors, as well as in healthy volunteers.

The study evaluates the feasibility and accuracy of using a CLDN18.2-specific PET imaging probe to visualize tumors. It investigates the diagnostic performance in identifying tumor lesions and compares imaging results with histopathology findings.

• Who can participate: Adults aged 18-70 years, both male and female, with a confirmed or suspected diagnosis of gastric cancer, pancreatic cancer, cholangiocarcinoma, or other malignant tumors, or healthy volunteers. Participants must be able to adhere to study procedures and provide informed consent.
• Study details: Participants will undergo PET imaging to visualize tumors. Healthy volunteers will have pharmacokinetic profiling to study the radiotracer's distribution and safety.