Positron emission tomography (PET) is a medical imaging technique that helps visualize metabolic processes in the body. It uses a small amount of radioactive material, called a radiotracer, which is injected into the patient. As the radiotracer emits positrons, it interacts with electrons in the body, producing gamma rays that are detected by the PET scanner. The resulting images provide detailed information about the function of organs and tissues, making PET useful for diagnosing conditions such as cancer, heart disease, and neurological disorders. It can also help monitor treatment effectiveness and disease progression over time.