Comparison of ⁶⁸Ga-DOTANOC and ¹⁸F-FDOPA PET/CT for Detection of Recurrent or Metastatic Paragangliomas

Purpose To evaluate the diagnostic performance of gallium 68 (⁶⁸Ga)-DOTA-NaI3-octreotide (⁶⁸Ga-DOTANOC) and fluorine 18 (¹⁸F)-fluoro-l-3,4-dihydroxyphenylalanine (¹⁸F-FDOPA) PET/CT in detecting recurrent or metastatic paragangliomas. Materials and Methods This single-center retrospective study included patients with paragangliomas who underwent both ⁶⁸Ga-DOTANOC PET/CT and ¹⁸F-FDOPA PET/CT between August 2021 and December 2023. The diagnostic performance of these two tracers in detecting recurrent or metastatic tumors was compared using several metrics, including sensitivity, negative predictive value, and accuracy. Results This study included 36 patients (median age, 52 years [range, 14-78 years]; 16 female, 20 male). Of these, nine underwent initial ⁶⁸Ga-DOTANOC and ¹⁸F-FDOPA PET/CT examinations before treatment, and the remaining 27 underwent posttreatment examinations. Twenty-two of those 27 patients had recurrence or metastasis. According to lesion-level analysis, ⁶⁸Ga-DOTANOC had higher sensitivity, negative predictive value, and accuracy for diagnosis of bone metastases than did ¹⁸F-FDOPA PET/CT (97% vs 78% [<i>P</i> < .001], 85% vs 42% [<i>P</i> = .02], and 97% vs 81% [<i>P</i> < .001], respectively). ¹⁸F-FDOPA PET/CT had higher sensitivity, negative predictive value, and accuracy for the diagnosis of liver metastases than did ⁶⁸Ga-DOTANOC PET/CT (73% vs 15% [<i>P</i> < .001], 68% vs 41% [<i>P</i> = .04], and 83% vs 46% [<i>P</i> < .001], respectively). According to patient-level analysis, the sensitivity of ¹⁸F-FDOPA PET/CT for diagnosing liver metastases was higher than that of ⁶⁸Ga-DOTANOC PET/CT (88% vs 25%; <i>P</i> = .04). Conclusion In patients with recurrent or metastatic paragangliomas, ⁶⁸Ga-DOTANOC PET/CT showed better performance than ¹⁸F-FDOPA PET/CT in detecting bone metastases, and ¹⁸F-FDOPA PET/CT performed better in detecting liver metastases. <b>Keywords:</b> ⁶⁸Ga-DOTANOC, ¹⁸F-FDOPA, Pheochromocytoma, Paraganglioma Published under a CC BY 4.0 license.