OTHER POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY TRACERS IN DIFFERENTIAL THYROID CARCINOMA ¡BEYOND THE USE OF 2-[18F]FDG

Thyroid cancer is a common endocrinological malignancy worldwide, accounting for 3% of the global incidence of all cancers. Meta-analyses, systematic reviews, and descriptive reviews mention the use of positron emission tomography / computed tomography (PET/CT) as an alternative to morphological imaging such as computed tomography or magnetic resonance imaging to clarify the diagnosis. The aim: analysis of positron emission tomography/computed tomography tracers in the differential diagnosis of thyroid carcinomas. Materials and methods: Review about PET/CT tracers different than 2-[18F] fluorodeoxyglucose (FDG) in patients with diagnosed differentiated thyroid carcinoma. Evidence Synthesis: PET/CT is an alternative to morphological diagnosis imaging when is inconclusive or negative due to the suspicion of tumor persistence or recurrence, elevation of tumor markers, dedifferentiation thyroid carcinoma, non-conventional therapeutic options. 2-[18F] FDG is the most uses a tracer, but there are scenarios where can be negative or inconclusive, for this reason, in recent years other PET tracers have been used: [124I] NaI, [18F] Tetrafluoroborate, [68Ga] Ga-NOTE-PRGD2 or [18F] AIF-NOTE-PRGD2, [68Ga] Ga-DOTA-FAPI, [18F] Fluorocholine or [11C] C-Choline, [18F] or [68Ga] Ga-PSMA, [68Ga] Ga DOTA-TATE/TOC/NOC/LAN, [18F]-FAZA, L-[methyl-11C] Methionine and [89Zr] DFO-PAS200-Fab. Conclusions. There are multiple radiopharmaceuticals different than 2-[18F] FDG, which can be adequate in the context of differentiated thyroid carcinoma: 2-[18F] FDG PET/CT negative, TENIS syndrome, radioiodine-refractory thyroid cancer suspected, thyroid dedifferentiated carcinoma, and some cases theragnostic tools.