Early experience with positron emission tomography (PET) has provided exciting results in the evaluation of a broad spectrum of
neoplasms, to include primary adrenal
tumors, their
metastases and metastatic disease to the adrenal glands. By virtue of the well-recognized propensity of
malignancies to preferentially use glycolysis as an important energy source and the stimulation of mechanisms designed to absorb substrate
glucose, the
glucose analog, [
18F]fluorodeoxyglucose, has become a successful
radiopharmaceutical in the scintigraphic evaluation of adrenal
tumors. Building upon prior experience gained with imaging the adrenal gland, other positron-labeled
radiopharmaceuticals are finding their way into clinical use. The 11b-hydroxylase inhibitor,
metomidate labeled with 11C has been used to scintigraphically identify tissues of adrenocortical origin, to accurately identify recurrent and metastatic
adrenocortical carcinoma and may be useful in assessing the malignant potential of these
tumors and predicting survival in afflicted patients. Adrenomedulla imaging with 11C- and 18F-labeled
catecholamines and
catecholamine analogs draws heavily from the experience gained from predecessor compounds, labeled with single photon emitting
isotopes and, in some instances, single photon emission tomography, and has been shown to depict with high efficacy
pheochromocytomas,
neuroblastomas and other
neoplasms of neural crest origin. Additional structural and functional information provided by computed tomography (CT), performed as part of hybrid PET/CT imaging directly complements PET and adds measurable diagnostic value in the evaluation of adrenal
tumors.