A gallium scan is a nuclear medicine test that uses a special camera to take pictures of specific tissues in the body after a radioactive tracer (radionuclide or radioisotope) makes them visible. Each type of tissue that may be scanned (including bones, organs, glands, and blood vessels) uses a different radioactive compound as a tracer. The radioactivity of different tracers decreases over a period of usually hours, days, or weeks. The tracer remains in the body temporarily before it is eliminated as waste, usually in the urine or stool (feces).

During a gallium scan, the tracer (radioactive gallium citrate) is injected into a vein in the arm. It travels through the bloodstream and into the body's tissues, primarily the bones, liver, intestine, and areas of tissue where inflammation or a buildup of white blood cells (WBCs) is present. It usually takes the tracer a few days to accumulate in these areas, so in most cases a scan is done at 2 days and repeated at 3 days after the tracer is injected. Areas where the tracer accumulates in higher-than-normal amounts show up as bright or "hot" spots in the pictures. The problem areas may be caused by infection, certain inflammatory diseases, or a tumor.

Why It Is Done

A gallium scan is done to:

• Detect the source of an infection that is causing a fever (called a fever of unknown origin).
• Detect an abscess or certain infections, especially in the bones.
• Monitor the response to antibiotic treatment.
• Diagnose inflammatory conditions such as pulmonary fibrosis or sarcoidosis.
• Detect certain types of cancer (such as lymphoma). A gallium scan also may be done to determine whether cancer has spread (metastasized) to other areas of the body, or to monitor the effectiveness of cancer treatment.

How To Prepare

Before the gallium scan, tell your doctor if:

• You are or might be pregnant.
• You are breast-feeding. If you will no longer be breast-feeding after the test, you will be asked to stop breast-feeding 2 weeks before the test so that the radioactive tracer will not accumulate in your breast tissue. If you will continue to breast-feed after the test, it is recommended that you not use your breast milk for 4 weeks after a gallium scan, since the tracer can be passed to your baby. Some doctors may recommend that you stop breast-feeding completely after this scan.
• Within the past 4 days, you have had an X-ray test using barium contrast material (such as a barium enema) or have taken a medicine (such as Pepto-Bismol) that contains bismuth. Barium and bismuth can interfere with test results.

Gallium accumulates in the large intestine (colon) before being eliminated in the stool. You may need to take a laxative the night before the scan and have an enema 1 to 2 hours before the scan to prevent the gallium in your colon from interfering with pictures of the area being studied.

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