Positron emission tomography tracers in medullary thyroid carcinoma: Current evidence and emerging targets

Table 1 Comparative diagnostic performance of positron emission tomography tracers in recurrent medullary thyroid carcinoma

Tracer	Ref.	Patient-based detection rate (sensitivity)	Lesion-based detection rate	Key correlate/finding
18F-FDOPA	Treglia et al[4], 2012	66% (pooled)	71% (pooled)	Sensitivity rises to 86% with Ctn > 1000 pg/mL
	Lee et al[5], 2020	Highest among 5 tracers (network meta-analysis)	N/A	Ranked 1 for patient-level detection
	Zhang et al[6], 2024	95% (single-centre cohort, n = 109)	N/A	High specificity (93%) and accuracy (94%)
18F-FDG	Cheng et al[13], 2012	68-69% (pooled)	N/A	General performance in recurrent/metastatic MTC
	Treglia et al[14], 2012	75% (with Ctn > 1000 pg/mL)	N/A	Sensitivity rises to 91% with CEA DT < 24 months
	Verbeek et al[15], 2012	77% positivity in patients with Ctn DT < 24 months	N/A	Strong correlation with aggressive disease
68Ga-SSTR	Treglia et al[17], 2017	63.5% (pooled)	N/A	Lower than FDOPA; comparable to FDG
	Hayes et al[18], 2021	26% show sufficient uptake for PRRT	N/A	Highlights limited PRRT eligibility
	Castroneves et al[19], 2018	100% for bone metastases	N/A	Superior to bone scintigraphy (44%) for bone lesions

This table summarizes the key diagnostic performance metrics from foundational meta-analyses and large cohort studies for the three main tracers. ¹⁸F-FDOPA: ¹⁸F-fluorodihydroxyphenylalanine; ¹⁸F-FDG: ¹⁸F-fluorodeoxyglucose; ⁶⁸Ga-SSTR: Gallium-68-labelled somatostatin receptor; Ctn: Calcitonin; DT: Doubling time; N/A: Not applicable; PRRT: Peptide receptor radionuclide therapy; MTC: Medullary thyroid carcinoma; CEA: Carcinoembryonic antigen; FDG: Fluorodeoxyglucose; FDOPA: Fluorodihydroxyphenylalanine.