A gallium scan is a
nuclear medicine test. A nuclear medicine test 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 a tracer decreases over a period of hours, days, or weeks. The tracer stays
in the body until it is eliminated as waste, usually in the urine or stool
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 often takes
the tracer a few days to build up in these areas, so in most cases a scan is
done at 2 days and again at 3 days after the tracer is injected. Areas where
the tracer builds up 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
- Monitor the response to
inflammatory conditions such as
pulmonary fibrosis or
- Detect certain types of
cancer (such as
lymphoma). A gallium scan also may be done to see if
cancer has spread (metastasized) to other areas of the body, or to watch how
well a cancer treatment is working.
How To Prepare
Before the gallium scan, tell your
- You are or might be pregnant.
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 build up 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 because the tracer can be passed
to your baby. Some doctors may advise you to stop breast-feeding completely
after this scan.
- Within the 4 days before the gallium scan, 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
Gallium builds up in the large intestine (colon) before it
is 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 mean. To
help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).