Precautions after PET-CT examination include the following: 1. PET-CT itself has radioactive metabolites, so it is recommended that patients stay away from infants, pregnant women and their families for 20 hours after the examination; because although more radioactive materials have been attenuated during the examination, the dose of radioactive materials still exists when the patient returns to the ward or home, and needs to be physiologically eliminated from the body itself, which will generally be completely attenuated after 20 hours; 2. Avoid patients walking around and going to and from public places or places with a high concentration of people as much as possible, and normal examination and treatment should be carried out in the ward, which has relatively little influence on the surrounding medical and nursing staff.