Test Overview
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.