MIBG Scan - Metaiodobenzylguanidine Scan
An MIBG scan uses iodine-123 labeled metaiodobenzylguanidine, taken up by nerve-type tumor cells, to map neuroblastoma in children and pheochromocytoma and paraganglioma in adults, to confirm eligibility for MIBG therapy and to assess the heart's nerve supply. The test runs over two days with thyroid protection tablets, and some medicines are stopped beforehand. Our nuclear medicine team reviews your medicines before booking.
About This Department
An MIBG scan follows a molecule that nerve-type tumor cells take up as if it were adrenaline. The scan maps neuroblastoma and adrenal tumors across the whole body.
An MIBG scan, or metaiodobenzylguanidine scan, is a nuclear medicine test in which a small dose of MIBG labeled with radioactive iodine-123 is injected into a vein and imaged with a gamma camera the next day. MIBG resembles noradrenaline, so cells of the sympathetic nervous system and tumors that grow from them absorb it. Oncologists rely on it to stage neuroblastoma in children. It also finds pheochromocytoma and paraganglioma, confirms eligibility for MIBG therapy and shows the heart's nerve supply in heart failure and some movement disorders. In 280 children with stage 4 neuroblastoma, those whose MIBG score fell to 2 or below after initial chemotherapy had a 3-year event-free survival of 44.9 percent, against 15.4 percent for higher scores (Yanik and colleagues, Journal of Nuclear Medicine, 2013). This page explains how the scan works, its uses, thyroid protection and medicines to stop, the two scan days, scans in children, reading the result, safety, and how patients from abroad arrange the test at Biruni Hospital in Istanbul.
What an MIBG scan is
The scan shows function rather than shape. It finds tumor cells in bone marrow and bone that CT and MRI can miss.
| Condition | Question answered | Who it is for |
|---|---|---|
| Neuroblastoma | Extent of disease, response to treatment, relapse | Children |
| Pheochromocytoma and paraganglioma | Location, spread, suitability for MIBG therapy | Adults and children |
| Heart failure | Sympathetic nerve damage in the heart, risk | Adults |
| Parkinson disease and Lewy body dementia | Loss of cardiac sympathetic nerves supports the diagnosis | Adults |
Neuroblastoma
| Curie score | Three-year event-free survival | Meaning |
|---|---|---|
| 2 or below | 44.9 percent | Good early response |
| Above 2 | 15.4 percent | Poor response, other treatment considered |
| 0 after transplant | 49.3 percent | No remaining MIBG-avid disease |
Metaiodobenzylguanidine scans are the most sensitive and specific method of staging and response evaluation in neuroblastoma, particularly when used with a semi-quantitative scoring method (Matthay and colleagues, British Journal of Cancer, 2010).
Pheochromocytoma and paraganglioma
Imaging then locates the tumor and shows whether there are others. Inherited forms, linked to genes such as SDHB, VHL and RET, often cause several tumors.
| Scan | Strength | When used |
|---|---|---|
| Ga-68 DOTATATE PET/CT | Highest sensitivity for most paragangliomas, especially SDHB-related | Staging and searching for spread |
| F-18 FDOPA PET/CT | Excellent for adrenal pheochromocytoma and head and neck tumors | Where available |
| I-123 MIBG scan | Confirms MIBG uptake | Before MIBG therapy, where PET is unavailable |
The heart and nervous system
Heart failure
The two-year event rate was 15 percent for patients with a heart-to-mediastinum ratio of 1.60 or higher and 37 percent for those below, and MIBG imaging provided independent prognostic value in heart failure (Jacobson and colleagues, Journal of the American College of Cardiology, 2010).
| Heart-to-mediastinum ratio | Two-year cardiac events | Meaning |
|---|---|---|
| 1.60 or higher | 15 percent | Sympathetic nerves relatively preserved |
| Below 1.60 | 37 percent | Higher risk of worsening, arrhythmia and cardiac death |
Preparation and medicines
Which medicines must be stopped before the scan?
| Medicine group | Examples | Usual stop time |
|---|---|---|
| Combined alpha and beta blockers | Labetalol | About 72 hours to one week |
| Tricyclic antidepressants | Amitriptyline, imipramine | One to three weeks |
| Sympathomimetics and decongestants | Pseudoephedrine, phenylephrine | About 48 hours |
| Some calcium channel blockers | Nifedipine, amlodipine | About 48 hours |
Iodine allergy
An allergy to iodine-containing X-ray contrast or shellfish does not prevent the scan, since the amount of iodine is tiny and chemically different. No special steps follow.
The two scan days
| Time | Step | Duration |
|---|---|---|
| Day before injection | Start thyroid blocking tablets | Once or twice daily |
| Day 1 | Injection | About 30 minutes including preparation |
| Day 2, about 24 hours later | Whole-body images and SPECT/CT | One to two hours |
The camera does not surround you tightly and makes no loud noise. Lying still is the only requirement.
| Image | What it covers | Time |
|---|---|---|
| Whole-body planar | Head to feet, front and back | About 30 to 45 minutes |
| SPECT/CT | 3D images of selected areas, matched with CT | About 20 to 30 minutes |
Why the scan takes two days
Time sharpens the picture.
Patience pays. Right after the injection, MIBG circulates in the blood and lights up many normal tissues. Over the next day the background clears through the kidneys while tumor cells hold on to the tracer, so images taken at 24 hours show the tumor against a much darker background. Uncertain findings get a second look at 48 hours. Cardiac and neurological scans follow a shorter schedule, with images at 15 minutes and 4 hours on a single day, because the nerve endings in the heart handle MIBG differently from tumors.
Scans in children
A parent can stay with the child throughout the scan, except pregnant mothers.
Before MIBG therapy
Reading the result
Normal organs take up MIBG too. Readers expect this.
The salivary glands, heart, liver, bowel and bladder all appear on a normal scan, and the normal adrenal glands sometimes show faintly. The nuclear medicine physician compares the pattern with what is expected, reads the SPECT/CT to pin down each spot, and reports areas of abnormal uptake, their location and, for neuroblastoma, the Curie or SIOPEN score. The written report follows within one to two working days. Images are compared with earlier scans whenever available, since the change over time decides treatment.
A negative scan needs context. One in ten neuroblastomas never take up MIBG, and for them a different scan is used from the start.
Safety
The radiation dose from an iodine-123 MIBG scan is modest, similar to a CT scan of the abdomen, and far below the therapy dose.
What to expect
- A brief warm feeling or rarely a rise in blood pressure during injection, which is why it is given slowly.
- No effect on how you feel afterwards in almost every case.
- Tracer leaves the body through the urine over the following days.
Pregnancy has to be excluded in women of childbearing age before the injection.
For patients from abroad
One coordinator from the international patients office handles arrangements from the first message through discharge and answers the same WhatsApp number once you are back home. The office works in English, Arabic, French, Russian, Serbian, Romanian and Spanish and books interpreters for other languages, and it arranges the visa invitation letter, airport transfers, daily transport and accommodation near the hospital. Halal, vegetarian and diabetic meals, a prayer room on site, and a female physician on request wherever the rota allows.
Cost
| Item | Included | Priced separately |
|---|---|---|
| Tracer and imaging | Iodine-123 MIBG, whole-body images, SPECT/CT | Additional PET scans |
| Preparation | Medicine review, thyroid blocking tablets | Sedation or anesthesia for children |
| Report | Nuclear medicine report, images on disc | Consultation with the treating specialist |
Ask for the quote once the medicine review is done, since changes to the date may affect the price.
References
- Yanik GA, Parisi MT, Shulkin BL, et al. Semiquantitative mIBG scoring as a prognostic indicator in patients with stage 4 neuroblastoma. A report from the Children's Oncology Group. J Nucl Med. 2013;54(4):541-548.
- Matthay KK, Shulkin B, Ladenstein R, et al. Criteria for evaluation of disease extent by 123I-metaiodobenzylguanidine scans in neuroblastoma. A report for the International Neuroblastoma Risk Group (INRG) Task Force. Br J Cancer. 2010;102(9):1319-1326.
- Jacobson AF, Senior R, Cerqueira MD, et al. Myocardial iodine-123 meta-iodobenzylguanidine imaging and cardiac events in heart failure. Results of the prospective ADMIRE-HF study. J Am Coll Cardiol. 2010;55(20):2212-2221.
- Bombardieri E, Giammarile F, Aktolun C, et al. 131I/123I-metaiodobenzylguanidine (mIBG) scintigraphy. Procedure guidelines for tumour imaging. Eur J Nucl Med Mol Imaging. 2010;37(12):2436-2446.
Editor's note
Written by the Biruni Hospital medical editorial team. Reviewed by Prof. Dr. Burçak YILMAZ, Nuclear Medicine.
Medically reviewed by
Prof. Dr. Burçak YILMAZ
Nuclear Medicine
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