The Role of 18F-FDG and 68Ga-FAPI PET/CT in the Diagnosis and the Efficacy Evaluation of Advanced Colorectal Cancer (peritoneal Metastasis With/without Other Metastases)

Inclusion Criteria: 1. Histologically confirmed colorectal cancer, clinical or other imaging suspicion of peritoneal metastasis with or without other distant metastases. 2. Patients voluntarily enrolled in this study by signing an informed consent form 3. Age ≥ 18 years 4. Expected life expectancy ≥ 3 months 5. Adequate organ and bone marrow function 6. Willingness to adhere to the study protocol and follow-up programme Exclusion Criteria: 1. Pregnant or breastfeeding women. 2. Patients with a history of other malignant diseases in the last 5 years, except cured skin cancer and carcinoma in situ of cervix 3. Severe mental disease, uncontrolled epilepsy, or central nervous system disease 4. Subjects with current concurrent interstitial pneumonitis or interstitial lung disease, or subjects with previous interstitial pneumonitis or interstitial lung disease requiring hormonal therapy, or subjects with other conditions that may interfere with the judgement and management of immune-related pulmonary toxicity, e.g., pulmonary fibrosis, organising pneumonia (e.g., occlusive bronchiectasis), pulmonary fibrosis, organising pneumonia (e.g., occlusive bronchiectasis), pneumoconiosis, Drug-associated pneumonia, idiopathic pneumonia, active pneumonia, or severe pulmonary impairment on CT; and active tuberculosis