What is an octreotide scan? Nuclear medicine uses radioactive materials to diagnose or treat diseases. An octreotide scan is one…Read more
An MIBG scan is a nuclear medicine scan that uses iodine-123 meta-iodobenzylguanidine – MIBG for short. An MIBG scan is commonly used for detection of neuroendocrine tumours, such as neuroblastoma and phaeochromocytoma. It can also aid in the detection of carcinoid and medullary thyroid carcinoma.
Results of serum and urinary catecholamines are necessary at initial presentation before approval of the scan by the nuclear medicine department. A history of previous neuroendocrine tumour is required for follow-up MIBG scans.
This study may not be suitable for pregnant women because of potential harm to the developing foetus. In pregnancy, the timing of the scan needs to be considered in relation to the benefit versus risk to the foetus: this should be discussed with the nuclear medicine specialist.
Women who are breast-feeding may need to make special preparations after the test to stop breast-feeding for a short time. Expressing and storing breast milk before the scan, followed by expressing and discarding the breast milk for 22 hours after the injection of the radiopharmaceutical should be considered to avoid unnecessary radiation to the infant.
See InsideRadiology: Nuclear Medicine for further information about the precautions to take with nuclear medicine studies for breast-feeding patients and those in close contact with children.
There is a relatively small risk of a transient increase in blood pressure at the time of the initial injection. The patient is generally monitored in the nuclear medicine department for this over the initial 30 minutes. Any hypertension usually resolves within 48 hours after injection and rarely requires medical therapy.
As I-123 is excreted in breast milk, if used in nursing mothers, formula feeds will need to be replaced for breast milk for at least 22 hours. For further details, please see InsideRadiology Nuclear Medicine: Referrer information.
Although the MIBG scan is the test of choice for detection of a phaeochromocytoma and neuroblastoma, at times poorly differentiated tumours can be MIBG-negative. In this case, detection is better achieved with positron-emission tomography (PET) scans. By contrast, PET scans can yield false negative results in well-differentiated, slow-growing tumours.
MIBG imaging performs better with a benign phaeochromocytoma, whereas octreotide and PET scans are more sensitive for detection of a malignant phaeochromocytoma.
Generally, MIBG imaging is superior to PET imaging for detecting well-differentiated neuroblastomas. However, PET is beneficial in tumours with aggressive or de-differentiated histology, that fail to concentrate MIBG or are weakly MIBG-positive.
Some neuroendocrine tumours, such as paragangliomas, can be MIBG-negative, but may be detected with indium 111-pentetreotide (octreotide scan) or DOTA-TATE (PET) scans.
If you require more information, please contact your nuclear medicine specialist to determine which nuclear medicine study would be the most appropriate for your patient.
Anatomic imaging with computed tomography and magnetic resonance imaging is often complimentary, as it is sensitive, but not specific for tumour type.
Page last modified on 18/5/2018.
RANZCR® is not aware that any person intends to act or rely upon the opinions, advices or information contained in this publication or of the manner in which it might be possible to do so. It issues no invitation to any person to act or rely upon such opinions, advices or information or any of them and it accepts no responsibility for any of them.
RANZCR® intends by this statement to exclude liability for any such opinions, advices or information. The content of this publication is not intended as a substitute for medical advice. It is designed to support, not replace, the relationship that exists between a patient and his/her doctor. Some of the tests and procedures included in this publication may not be available at all radiology providers.
RANZCR® recommends that any specific questions regarding any procedure be discussed with a person's family doctor or medical specialist. Whilst every effort is made to ensure the accuracy of the information contained in this publication, RANZCR®, its Board, officers and employees assume no responsibility for its content, use, or interpretation. Each person should rely on their own inquires before making decisions that touch their own interests.