Positron emission tomography (PET) is an established imaging method in oncology. PET/computed tomography (PET/CT) and PET/magnetic resonance imaging (PET/MRI) are hybrid techniques which combine morphological information obtained by CT and MRI with functional data provided by PET. Several PET radiotracers evaluating different metabolic pathways or receptor status can be used to assess endocrine
tumors such as thyroid
tumors or neuroendocrine
neoplasms (NENs). This review is focused to describe the role of PET imaging using different radiotracers in patients with thyroid
tumors and NENs. The role of PET imaging with different radiotracers in several endocrine
tumors including thyroid
tumors, gastroenteropancreatic
neoplasms, lung neuroendocrine
neoplasms,
pheochromocytomas and
paragangliomas, and
multiple endocrine neoplasia syndromes has been described.
Fluorine-18 fluorodeoxyglucose (18F-FDG) PET evaluating the
glucose metabolism provides useful diagnostic and prognostic information in patients with thyroid
tumors.
Iodine-124 (124I) assessing the
iodine metabolism may be used for dosimetry and diagnostic purposes in thyroid
tumors. In patients with NENs specific radiotracers can be used for diagnostic purposes such as
somatostatin analogues labeled with
gallium-68 (68Ga-DOTA-peptides) evaluating
somatostatin receptor expression and
fluorine-18 fluorodihydroxyphenylalanine (18F-FDOPA) assessing the uptake, decarboxylation and storage of
amine precursors. One advantage of 68Ga-DOTA-peptides PET is to select patients with well-differentiated and inoperable NENs for
peptide receptor radionuclide therapy.
18F-FDG PET may provide useful prognostic information in patients with high-grade NENs. PET imaging with different radiotracers is a useful functional imaging technique in the work-up of several endocrine
tumors.