A Prospective Study on the Diagnosis of Malignant Tumors With 18F-FGIn PET/CT

Inclusion Criteria: 1. Patients with clinical suspicion or exclusion of primary or recurrent malignant tumors (such as glioma of the brain, liver cancer, gastric cancer, duodenal cancer, colorectal cancer, ovarian cancer, etc., where 18F-FDG is prone to false negatives and false positives) 2. Patients undergoing tumor staging or evaluating treatment effect using 18F-FDG PET/CT or 18F-FGln PET/CT to determine the most appropriate treatment strategy 3. Patients without other tumor history 4. Patients with good compliance, providing informed consent, and able to follow the research protocol Exclusion Criteria: 1. pregnant or lactating patients or patients under 18 years old 2. the subjects and their parents or legal representatives are unable or unwilling to provide written informed consent; 3. patients with poor compliance, unable to tolerate or cooperate with PET/CT examinations. 4. those who have undergone gastrointestinal barium meal examination within one week; 5. other situations where the investigators consider it inappropriate for the subjects to participate in this clinical trial