A gallbladder radionuclide scan is an imaging test that uses safe amounts of radiation to detect infection, disease, or blockage in your gallbladder. It uses radioactive “tracers” injected into your bloodstream that are viewed under specialized imaging equipment.
The gallbladder is a small organ near your liver that stores bile made in the liver. Bile is a greenish or yellowish liquid secreted by the liver that helps 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 and hepatobiliary iminodiacetic acid scan (HIDA).
A gallbladder radionuclide scan is done to help detect potential problems with your gallbladder or ducts near the gallbladder, such as
- bile duct blockage
- cholecystitis (gallbladder inflammation)
- bile leakage
- birth defects
It can also be used to test your gallbladder ejection fraction and the rate at which your gallbladder releases bile.
There is a risk of exposure to radiation with this test. The gallbladder radionuclide 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. The benefits of the tests outweigh the risk of radiation exposure (Radiology, 2012).
There is, however, a rare chance of an allergic reaction, which is typically mild.
Pregnant women, or women who believe they could be pregnant, shouldn’t undergo the test. The levels of radiation emitted by the tracers are considered safe for adults. However, they are unsafe for developing fetuses, which are more sensitive to radiation.
Inform 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 may include:
- fasting for four hours before the test
- removing all jewelry
- changing into a hospital gown
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 or nutritional supplements.
Also, 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, meaning you can go home when your gallbladder radionuclide scan is complete.
The machine doing 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 changing into a hospital gown and lying flat on a scanning table. A trained specialist will insert an IV needle into your arm and deliver a medication with radiotracers in them. These tracers travel through your bloodstream, work their way into your gallbladder and 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. 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 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 immediately, 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 your doctor has a higher level of certainty regarding your condition.