PET-CT side effects: PET-CT examination is a non-invasive examination, the injection of the imaging agent and positioning of the required CT on the human body has a certain degree of radiation, but the dose is extremely small, within the acceptable range of the human body, after the examination, drink more water, the body of the radioactive drug metabolized through the urine of the metabolism of the body, generally more than 6 hours completely metabolized. PET-CT adaptive population: 1, people with family history of tumor 2, people with abnormal tumor markers 3, people who have been exposed to carcinogenic substances 4, people with pre-cancerous lesions 5, tumor patients who need to know about tumor recurrence, metastasis, or related conditions 6, health checkups for screening tumors above forty years old.