Positron emission tomography, or PET, is a medical imaging technique that helps doctors see how organs and tissues in the body are functioning. It works by using a small amount of radioactive material, called a tracer, which is injected into the body. This tracer emits positrons, which are tiny particles that interact with electrons in the body, producing gamma rays that can be detected by the PET scanner. The PET scanner creates detailed images that show areas of high and low activity, helping to identify conditions like cancer, heart disease, and brain disorders. By observing how the tracer moves and accumulates, doctors can gain valuable insights into a patient's health and make informed treatment decisions.