An MIBG scintiscan is a type of imaging test. It uses a radioactive substance (called a tracer) and a special scanner to find or confirm the presence of pheochromocytoma and neuroblastoma. These are types of tumors that affect the nervous tissue.
A radioisotope (MIBG, iodine-131-meta-iodobenzylguanidine) is injected into a vein. This compound attaches to specific tumor cells.
You will have the scan later that day or the next day. For this part of the test, you lie on a table under the arm of the scanner. Your abdomen is scanned. You may need to return for repeated scans for 1 - 3 days. Each scan takes 1 - 2 hours.
Before or during the test, you may be given an iodine mixture. This prevents your thyroid gland from absorbing too much of the radioisotope.
How to Prepare for the Test
You will need to sign an informed consent form. You will be asked to wear a hospital gown or loose fitting clothes. You will need to take remove jewelry or metal objects before each scan.
How the Test will Feel
You will feel a sharp needle prick when the material is injected. The table may be cold or hard. You must lie still during the scan.
Why the Test is Performed
This test is done to help diagnose pheochromocytoma when an abdominal CT scan does not give a definite answer. It is also used to help diagnose neuroblastoma.
There are no signs of a tumor.
What Abnormal Results Mean
Most often, this test is used to locate pheochromocytoma.
It may be also be useful to detect multiple tumors or tumors that are located outside the adrenal tissues.
There is some exposure to radiation from the radioisotope. The radiation from this radioisotope is fairly high compared to most others, so you may need to take some extra steps for a few days after the test. Your health care provider will tell you what actions to take.
Before or during the test, you may be given an iodine solution to help keep your thyroid gland from absorbing too much iodine.
This test should NOT be done on pregnant women because of the danger to the unborn baby from radiation.
Aslam S, Sohaib A, Rockall A, Bomanji JB, Evanson J, Roznek RH. Imaging of the endocrine system. 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 71.
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.
Young WF Jr. Adrenal medulla, catecholamines, and pheochromocytoma. In: Goldman L, Ausiello D, eds. Cecil Medicine. 2th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 235.
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.