Your healthcare provider may recommend a nuclear medicine procedure to diagnose or treat a health problem. Nuclear medicine is used to show how the organs or tissues are functioning. For most diagnostic procedures, a tracer, which contains the radioactive material, is injected, swallowed, or inhaled. Then the radiologist uses a radiation detector to see how much of the tracer is absorbed or how it reacts in the organ or tissue. This will give the provider information about how well it is functioning. Common uses of nuclear medicine for diagnosis include: scans of the heart, lung, kidneys, gallbladder, and thyroid.