Renal Scan

A renal scan (also kidney scan, renogram) is a nuclear medicine exam in which a small amount of radioactive material is used to evaluate the kidneys.

To obtain detailed information about the kidneys and how they are functioning—for example size, shape and how much blood each kidney filters over time. Doctors may look for signs of kidney failure, perfusion or obstruction. A renal scan is frequently performed after a kidney transplant to screen for transplant rejection.

During a kidney scan, a radioactive substance (tracer) is injected into a vein in the arm and then travels through the bloodstream to the kidneys. The tracer flows through the blood vessels in the kidneys. “Hot spots” occur where the tracer shows up in above-average amounts, such as seen with some types of cancer. Areas where the tracer does not show up appear as dark or “cold” spots. Cold spots can indicate narrowing or blockage of the blood vessels, pockets of fluid, some cancers, or infection.

Remove jewelry, dentures, and metallic objects before the scan. You will be asked to wear a hospital gown. You will lie flat on your back on an exam table. A radioactive tracer will be injected into your arm vein. Once absorbed, a special gamma camera will obtain images of your kidneys. After the scan, no recovery time is required. You may be asked to drink plenty of fluids and urinate frequently to help remove the radioactive material from the body.  The images will be reviewed by a specialist and the results sent to your physician. Your physician will discuss these results with you during a follow up appointment.

Tell your doctor if you take any nonsteroidal anti-inflammatory drugs (NSAIDs) or blood pressure medications, as they could interfere with the exam. You may be asked to drink additional fluids before the scan. Follow your doctor’s written or verbal instructions.