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An MIBG scan is a test that helps locate and diagnose certain types of tumors. It can also show when cancer responds to therapy.
The letters MIBG stand for meta-iodobenzylguanidine. It is a protein that is absorbed by some tumors, particularly neuroblastoma. The scan can show neuroblastoma inside the body and when it has spread to the bone and other organs.
The test has 2 parts conducted over a 2-day period, but patients do not have to be admitted into the hospital for the test.
The first day of the test, patients receive an injection of a tracer, which is the MIBG compound combined with a very small amount of a radioactive substance (radioactive iodine). Neuroblastoma cells should absorb the tracer and show up when scanned. The second day of the procedure, patients have the scan, which uses a gamma camera that takes pictures of areas where the tracer has been absorbed. Doctors look for bright spots, which may indicate cancer.
The MIBG scan is a nuclear medicine test because it uses a very small amount of radioactive iodine. Nuclear medicine specialists use the ALARA principle (As Low As Reasonably Achievable). They carefully select the amount of radiotracer to provide an accurate test with the least possible radiation exposure. The dosage is determined by the patient’s body weight, the reason for the study, and the body part being imaged. Medical teams have performed these procedures for more than 50 years in adults and for more than 40 years in infants and children without any known adverse effects.
Source: Society of Nuclear Medicine and Molecular Imaging
Some medications can interfere with a MIBG scan. These drugs include certain antidepressants, anti-nausea, and blood pressure medications: amitriptyline (Elavil® ), imipramine (Tofranil® ), desipramine (Norpramin® ), nortriptyline (Aventyl® or Pamelor® ), labetalol (Trandate® ), promethazine (Phenergan® ), chlorpromazine (Thorazine® or Largactil® ), thioridazine (Mellaril® ), haloperidol (Haldol® ), and prochlorperazine (Compazine® or Compro® ).
If the patient takes any of these medicines, parents should not stop giving them on their own. A member of the pharmacy staff should contact parents to review their child’s medicines. The team member will tell parents whether to stop giving any medications to their child. Parents should consult their child’s doctor, nurse, or a member of the pharmacy staff with questions.
Patients should not take medications with pseudoephedrine or phenylephrine, which are found in many over-the-counter cold medicines. These substances can interfere with the scan. Parents should consult their child’s pharmacist before starting any prescription or over-the-counter medicines.
The results of the scan will be interpreted by a nuclear medicine physician. The doctor will prepare a report and share it with the physician who ordered the test. The patient’s oncologist will share the results with the family.
Together does not endorse any branded product mentioned in this article.
Reviewed: June 2018