Cerebral flow imaging includes cerebral perfusion tomography, 133Xe cerebral flow measurement and imaging, and stress test cerebral perfusion imaging. This test is used for the diagnosis of cerebral ischemia, cerebral infarction and the diagnosis and differential diagnosis of progeria and the localization of epileptic foci. Normal image: higher radioactivity of cerebral cortex, basal ganglia, thalamus and cerebellum on both sides, clear image, uniform distribution of radioactivity, and basically symmetrical distribution. The images in the three tomographic planes of transverse brain, coronal and sagittal views do not show any foci. Not suitable for: Patients who are allergic to potassium perchlorate and imaging agents. Contraindications before examination: Stop taking sedatives, stimulants and other drugs that act on the nervous system 24 hours before the examination to avoid the formation of artifacts during the examination, which may affect the judgment of the examination results. 30 min before the examination, take 400 mg of potassium perchlorate orally to close the choroid plexus; 10 min before the injection of the imaging agent, put on the black eye mask and earplugs until 10 min after the injection before removing them, and keep the eyes closed and rest quietly before the imaging. Requirements during the examination: The examination must be carried out within 3 hours after meals. If you cannot eat before the examination, you should listen to the doctor’s arrangement and take 50 grams of powdered sugar liquid orally or inject 50% glucose 40 ml intravenously to prevent the results of the examination from being affected by hypoglycemia. The head should not be moved during the examination to ensure the authenticity of the image.