Photon Emission Tomography (PET) is a medical imaging technique that allows doctors to observe metabolic processes in the body. It works by injecting a small amount of radioactive material, called a radiotracer, into the patient. This tracer emits gamma rays as it decays, which are then detected by a special camera to create detailed images of organs and tissues. PET scans are particularly useful for diagnosing conditions such as cancer, heart disease, and neurological disorders. By highlighting areas of increased or decreased activity, PET helps healthcare professionals assess the function of various organs and plan appropriate treatments.