Before PET-CT examination, first of all, we need to control blood sugar. 18F-FDG is a glucose derivative, which requires high blood sugar, so patients must control their blood sugar below 11.1 mmol/L, and try to control it below 8 mmol/L; on the day of examination, patients should not bring metals, such as hairpins, jewelry and other highly dense substances, so as not to interfere with PET images and CT images; in addition, PET In addition, the PET-CT center has prepared the patient’s clothing for the examination, which can minimize the negative factors. Since PET-C is an expensive and complex test, patients are required to strictly follow the pre-test preparation to ensure the quality of diagnostic images.