An RBC nuclear scan uses small amounts of radioactive material to mark (tag) red blood cells (RBCs). Your body is then scanned to see the cells and track how they move through the body.
The procedure may vary a little depending on the reason for the scan.
The RBCs are tagged with radioisotope in 1 of 2 ways.
The first method involves removing blood from a vein.
The second method involves an injection of medicine.
Scanning may be done right away or after a delay. For the scan, you will lie on a table under a special camera. The camera detects the location and amount of radiation given off by the tagged cells.
A series of scans may be done. The specific areas scanned depend on the reason for the test.
You will need to sign a consent form. You put on a hospital gown and take off jewelry or metallic objects before the scan.
You may feel a little pain when the needle is inserted to draw blood or to give the injection. Afterward, there may be some throbbing.
The x-rays and radioactive material are painless. Some people may have discomfort from lying on the hard table.
This test is most often done to find the site of bleeding in patients who have blood loss from the colon or other parts of the gastrointestinal tract.
Asimilar test called a ventriculogram may be done to check heart function.
A normal exam shows no rapid bleeding from the gastrointestinal tract.
Your health care provider will determine the meaning of abnormalities on the scan.
Veins and arteries vary in size. Getting a blood sample from some people may be than from others.
Other slight risks from having blood drawn include:
There is a small exposure to radiation from the radioisotope. There is very little radiation the materials break down so they are not radioactive in a very short time. Almost all radioactivity is gone in about 12 hours. There are no known cases of injury from exposure to radioisotopes. The scanner only detects radiation -- it does not give off radiation.
Most nuclear scans (including an RBC scan) are not recommended for women who are pregnant or breastfeeding.
Scans may need to be repeated over 1 or 2 days to detect gastrointestinal bleeding.
Jensen DM. Gastrointestinal hemorrhage and occult gastrointestinal bleeding. In: Goldman L, Schaefer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders; 2011:chap 137.
Segerman D, Miles KA. Radionuclide imaging: general principles. In: Adam A, Dixon AK, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 7.
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.
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