A gallbladder radionuclide scan is an imaging test that uses radiation to detect infection, disease, bile fluid leakage, or blockage in your gallbladder. The procedure uses radioactive “tracers” injected into your bloodstream that are viewed under specialized imaging equipment.

The gallbladder is a small organ underneath your liver that stores bile. Bile is a greenish or yellowish liquid secreted by the liver that helps to digest and absorb fat. Even though the gallbladder performs an important function, your body can survive without it.

The gallbladder radionuclide scan is also called hepatobiliary imaging, or hepatobiliary iminodiacetic acid scan (HIDA).

A gallbladder radionuclide scan is done to help detect potential problems with your gallbladder or ducts near the gallbladder. Problems may include:

  • bile duct blockage
  • cholecystitis (gallbladder inflammation)
  • gallstones
  • bile leakage
  • birth defects (in these cases, the scan is done on newborns or young children)

The procedure can also be used to test your gallbladder ejection fraction (the percentage of total bile that gets produced during a certain period of time) and the rate at which your gallbladder releases bile.

There is a risk of exposure to radiation with this test, as the scan uses small amounts of radioactive tracers. However, this test has been used for over 50 years and there are no known long-term side effects from such low doses of radiation.

There is a rare chance of an allergic reaction, which is typically mild.

Pregnant women or women who believe they could be pregnant should not undergo the test. While the levels of radiation emitted by the tracers are considered safe for adults, they are unsafe for developing fetuses. You should tell your doctor if there is a chance that you are pregnant before agreeing to have the scan.

Your doctor will give you complete instructions on how to prepare for your gallbladder radionuclide scan. These instructions may include fasting for four hours before the test.

At appointments before the scan, your doctor will perform a physical examination and take your complete medical history. Tell your doctor about any allergies you have and any medications you are taking, including over-the-counter medications or nutritional supplements.

Let your doctor know if you have problems lying still for an extended period, as the test can take up to 90 minutes.

The procedure is typically done on an outpatient basis, which means you can go home when your gallbladder radionuclide scan is complete.

The machine completing the scan looks like a large metal donut with a table coming out of it. There will be two large, block-like objects in front of the machine. These are part of the gamma camera that help doctors view your gallbladder.

You’ll begin by removing all jewelry and changing into a hospital gown. You will then lie flat on a scanning table. A trained specialist will insert an IV needle into your arm and deliver a medication with radiotracers. The tracers travel through your bloodstream, work their way into your gallbladder, and move through the bile ducts attached to it.

When the medication (radionuclide) has properly absorbed into your body, the scan portion of the test begins. The technician will slide you into the machine feet-first and your head will remain outside of the machine. You will be instructed to hold still while the scan is in progress. This may be uncomfortable, but it helps the machine to achieve clear images. The machine will pass back and forth over your abdomen while the gamma camera continuously takes images.

Your doctor will be watching the scan on a monitor as the tracers move through your body. When the tracers reach your small intestines, the scan is over.

After the scan, you’ll be instructed to drink plenty of water so the excess radioactive tracers can be flushed from your body.

You may get your test results within hours (if your doctor requested a stat reading), or your doctor may want to review them with you later.

The images from the scan are in black and white. Concentrated dark areas signify the concentration of the radioactive tracers. If no tracers are found on the scan or the scan moved slowly, there may be blockage issues or problems with your liver. If the tracers are found in other areas, this could indicate a leak.

If the results of your gallbladder radionuclide scan show problems, your doctor may choose to take immediate action. This could include surgery or medication. In all likelihood, you’ll undergo more testing so that your doctor has a higher level of certainty regarding your condition.