| Abstract: |
Nuclear medicine imaging utilizes several radiopharmaceuticals that have the potential to evaluate adrenal cancers such as neuroblastoma, pheochromocytoma and adrenocortical carcinoma. Each of these tumors have distinct biologic characteristics and distinguishing features. Adrenocortical carcinomas are rare aggressive malignancies that are often associated with metastatic disease at presentation and carry poor prognosis. Cross-sectional imaging is useful in characterizing the anatomical extent while metabolic imaging using F-18-fluorodeoxyglucose (18F-FDG) positron-emission tomography (PET) has been employed for accurate disease detection and is frequently used to assess locoregional nodal and distant metastases. Pheochromocytomas are neoplasms of the adrenal medulla that are often benign, but up to 10-15% of cases are malignant. Radiopharmaceuticals targeting norepinephrine transporters (NET) such as I-123 or I-131 labeled metaiodobenzylguanidine (MIBG) have been found to be especially helpful for confirming and excluding multifocal or metastatic disease. Somatostatin receptor-based scintigraphy and other PET radiopharmaceuticals such as 18F-FDG, 18F-fluorodopamine and 18F-fluorodihydroxyphenylalanine have also been utilized for imaging pheochromocytomas. Neuroblastoma, a neuroendocrine tumor with adrenal medulla as the most common site of involvement, is the most common extracranial solid tumor in children. Functional imaging using 123I-MIBG is routinely used in the initial staging and follow-up, and also has a role in response assessment, prognostication and detection of unsuspected relapses that are otherwise undetectable on other modalities. Other radiopharmaceuticals such as radiolabeled somatostatin receptor analogs and metabolic tracers have also been used while new PET radiotracers such as F-18-meta-fluorobenzylguanidine (18F-MFBG) and Copper-64 based radiopharmaceuticals are showing promising early results in patients with neuroblastoma. Appropriate choice of radiopharmaceuticals based on tumor characteristics is important to enable accurate evaluation of disease and guide subsequent patient management. The aim of this chapter is to review the role of functional imaging in details, discuss the current status of state-of-the-art techniques and emerging radiopharmaceuticals in the evaluation of adrenal malignancies. © 2022 Elsevier Inc. All rights reserved. |
