Gallium Scan

Why It Is Done

A gallium scan is done to:

• Find the source of an infection that is causing a fever.
• Look for an abscess or certain infections, especially in the bones.
• Check the response to antibiotic treatment.
• Diagnose inflammatory problems such as pulmonary fibrosis or sarcoidosis.
• Find certain types of cancer (such as lymphoma). The scan also may be done to see if cancer has spread (metastasized) to other areas of the body. Or it may check how well a cancer treatment is working.

How To Prepare

Before this test, tell your doctor if:

• You are or might be pregnant.
• You are breastfeeding.
  • If you plan to no longer feed your baby your breast milk after the test, stop breastfeeding 2 weeks before the test. The radioactive tracer will not build up in your breast tissue.
  • If you will continue to breastfeed after the test, talk with your doctor about how long to wait to use your milk after the test. Many doctors suggest waiting 4 weeks before you give your breast milk to your baby. This is because the tracer can pass to your baby. Some doctors may advise you to stop breastfeeding completely after this scan.
• Within the 4 days before the scan, you have:
  • Had an X-ray test using barium contrast material. This includes a barium enema.
  • Taken a medicine that contains bismuth, such as Pepto-Bismol.
  Barium and bismuth can affect the test results.

Gallium builds up in the large intestine before your body gets rid of it as stool. So you may need to take a laxative the night before the scan. You may also need an enema 1 to 2 hours before the scan. This is to help your doctor more clearly see the areas of your body that are being studied.

Talk to your doctor about any concerns you have about the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).

How It Is Done

A gallium scan is usually done by a nuclear medicine technologist. In most cases, a radiologist or nuclear medicine specialist will interpret the scan pictures.

The technologist will clean a site on your arm and then inject a small amount of radioactive tracer. You will need to come back for the scans. Gallium scans are usually done 24 hours (1 day), 48 hours (2 days), and 72 hours (3 days) after the tracer is injected.

When you come in for the scan, you may need to remove your jewelry. You may also need to take off all or most of your clothes. It depends on which area is being examined. You will be given a cloth or paper to cover yourself during the test.

You will lie on your back on a table. A large camera will be close above you. The camera will scan for radiation released by the tracer. It will make pictures of the tracer in your tissues. The camera may move slowly above and around your body. The camera does not produce any radiation, so you are not exposed to more radiation while the scan is being done.

You may be asked to move into different positions so the area of interest can be viewed from other angles. You need to lie very still during each scan to avoid blurring the pictures. You may be asked to hold your breath briefly during some of the scans.

Each scan may take about 60 to 90 minutes.

How It Feels

You may feel nothing at all from the needle puncture when the tracer is injected. Or you may feel a brief sting or pinch as the needle goes through the skin. Otherwise, a gallium scan usually causes no pain. You may find it hard to stay still during the scan. Ask for a pillow or blanket to make yourself as comfortable as you can before the scan begins.

What Affects the Test

You may not be able to have the test, or the results may not be helpful, if:

• You are pregnant. A gallium scan is not usually done during pregnancy because the radiation could harm the baby (fetus).
• You have barium or bismuth in your system. If a gallium scan is needed, it should be done before any tests that use barium (such as a barium enema). Taking a medicine (such as Pepto-Bismol) that contains bismuth can also affect the test.
• You can't stay still during the test.

What To Think About

• A gallium scan is used for certain types of cancers. Mainly it's for cancers of the lymph nodes, bones, or bone marrow. A normal scan does not rule out the possibility of cancer, though. That's because some types of cancer don't show up on a gallium scan. This type of scan also can't tell if a tumor is cancerous (malignant) or noncancerous (benign).
• Your doctor will interpret the results of the scan along with the results of other tests, such as a physical exam, blood tests, and X-rays. In many cases, results from an MRI test or positron emission tomography (PET) scan may be as accurate as the results from a gallium scan.
  • Magnetic Resonance Imaging (MRI)
  • Positron Emission Tomography (PET)
• If other nuclear scanning tests need to be done, they should be scheduled before a gallium scan. This is because the gallium tracer stays in the body longer than other tracer compounds.