Adrenal Medulla Scintigraphy
When is this exam indicated?
- Pheochromocytoma, to confirm the site or multiple sites (multifocality) and to search for possible recurrences and evaluate the possibility of a radiometabolic therapy;
- paraganglioma and neuroblastoma;
- medullary thyroid carcinoma;
- multiple endocrine neoplasms (MEN I and MEN II type).
- Medullary-renal scintigraphy is accessed if the patient is found to have:
- elevated urinary concentrations of vanilmandelic acid and its derivatives;
- increased plasma catecholamines;
- suspicious adrenal lesions on CT and/or MRI;
- elevation of neural crest tumor markers.
How is it performed?
Meta-iodobenzyl-guanidine (MIBG) marked with Iodine 131 or 123 and injected intravenously is used.
The radiopharmaceutical analogues of guanethidine accumulate in the pre-synaptic nerve endings of the adrenergic system and in the cytoplasmic granules of the chromaffin cells of the neural crest.
PREPARATION AND SIDE EFFECTS
The patient drinks a 2% Lugol's solution for 3-4 days before delivery of the radiopharmaceutical and for the duration of the investigation.
The examination takes approximately 30 minutes and is performed in three sessions (at 24, 48, and 72 hours after tracer intake).
Reserpine, MAOIs, tricyclic antidepressants are drugs that inhibit adrenal absorption.
Allergy to iodinated contrast medium.