Kidney Scan: What to Expect

A kidney nuclear medicine scan is a test to check how your kidneys look and how well they are working. Doctors also call it a renal scan, renal imaging, or renal scintigraphy.

Your doctor may recommend that you get this scan because it offers information that other tests -- such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) -- can’t provide.

The test uses a small amount of radioactive material that’s inserted into your body. A special camera and computer detect traces of that material in your kidneys in order to make images.

Why Do I Need It?

This test can help show how well each kidney is working, as well as problems that affect how both kidneys work, including:

  • Blood flow problems in the arteries that supply your kidneys
  • Tumors or cysts
  • Pockets of infection (abscesses)
  • Other kidney diseases
  • Your body rejecting a transplanted kidney

Are There Risks?

The amount of radioactive material used is small, so the risk is low.

A few people do have allergic reactions. You have to stay still during the test, and that’s uncomfortable for some people.

If you have any of these conditions or issues, you should let your doctor know in advance:

  • You’re pregnant or might be pregnant. The scan could be unsafe for your baby.
  • You’re breastfeeding. The radioactive material could taint your breast milk.
  • You’re allergic to any medicines or sensitive to latex.
  • You’re claustrophobic. The camera may move very close to you during the scan.

How to Prepare

Your doctor will let you know whether you need to drink extra fluids before your scan or whether your bladder should be empty.

Tell your doctor about any vitamins and supplements you take and whether you take aspirin, ibuprofen, or naproxen. These are a type of pain medicine called non-steroidal anti-inflammatory drugs (NSAIDs).

You should leave your jewelry at home. You may need to wear a gown during the scan.

Certain things can affect your test and make it less accurate. Let your doctor know if:

  • You’ve had another test with radioactive material recently, because you might still have some present in your body.
  • You’ve had a barium test recently, because it might still be in your digestive tract.
  • You take diuretics or medicine for your heart or high blood pressure.
  • You’ve had an “intravenous pyelogram test” (a type of kidney X-ray that uses a contrast material) within the last 24 hours.

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What Happens

To start the procedure, you’ll get an intravenous line (IV) in your hand or arm. The radioactive material, also called a tracer, will pass through the IV. You could get a metallic taste in your mouth briefly.

You may have to wait for the tracer to collect in your kidneys. When it’s time for the scan to begin, you’ll either lie or sit on the scanning table. The camera might move around you, or you might have to change positions to allow images from different angles.

You may have to wait while the technician makes sure all the images are of good quality. It’s possible that you’ll have to repeat some positions to capture better images or additional views. If you do, it doesn’t necessarily mean your doctor saw anything bad on your scan.

Depending on the specifics of your test, your scan could take as little as 30 minutes or as long as 2 hours.

When the test is over, your IV comes out and you’re ready to go home. You may be encouraged to drink lots of fluids for 24 hours. Emptying your bladder often will flush the tracer from your system.

If you develop any redness, pain, or swelling at the site of your IV, let your doctor know. You might have an infection or a reaction to the tracer.

What About My Results?

Your scan will go to a radiologist or other physician trained to read the images. Then a report will go to the doctor who ordered the test, and you’ll get the results.

WebMD Medical Reference Reviewed by Minesh Khatri, MD on January 18, 2017

Sources

SOURCES:

Urology Care Foundation: “What Is a Kidney (Renal) Nuclear Medicine Scan?”

NorthShore University Health System: Renal Scan.

Radiological Society of North America: Renal Scintigraphy.

National Cancer Institute: Dictionary of Cancer Terms.

Johns Hopkins Medicine Health Library: Kidney Scan.

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