68Ga]Ga-DOTA-TOC PET/CT in the localization of head and neck paraganglioma compared with [18F]FDOPA PET/CT and [123I]MIBG SPECT/CT

Abstract

Purpose18F-Fluoro-L-dihydroxyphenylalanine ([18F]FDOPA) PET offers high sensitivity and specificity in the imaging of non-malignant head and neck paraganglioma (HNPGL) but lower sensitivity in metastatic disease of these neuroendocrine tumours (NET). In contrast to the radiotracer [18F]FDOPA, both 123I-meta-iodo-benzylguanidine ([123I]MIBG) and 68Ga-DOTA-Tyr3-octreotide ([68Ga]Ga-DOTA-TOC) offer valuable clinical information on norepinephrine and somatostatin (SST) receptor status for planning 131I-MIBG and radionuclide peptide therapy (PRRT), respectively.Therefore, we compared [68Ga]Ga-DOTA-TOC and [18F]FDOPA PET/CT with [123I]MIBG planar and SPECT/CT imaging, for the detection of HNPGL. Combined cross-sectional imaging was the reference standard. MethodsA total of 3 men and 7 women (age range 22 to 73 years) with anatomical and/or histologically proven HNPGL were included in this study. Of these patients, 3 patients had metastatic HNPGL. Comparative evaluation included morphological imaging with CT and functional imaging with [68Ga]Ga-DOTA-TOC and [18F]FDOPA PET, including [123I]MIBG imaging. The imaging results were analysed on a per-patient and per-lesion basis. ResultsOn a per-patient analysis, the detection rate of both [68Ga]Ga-DOTA-TOC PET/CT and [18F]FDOPA PET/CT was 100%, that of planar [123I]MIBG imaging 10.0% and that of SPECT/CT 20.0%.On a per-lesion basis and in reference to diagnostic CT, the sensitivity of [68Ga]Ga-DOTA-TOC PET/CT was 100% (McNemar, P < 0.5), that of [18F]FDOPA PET/CT was 66.7% (McNemar, P < 0.01), that of planar [123I]MIBG imaging was 3.7% (McNemar, P < 0.0001), and that of SPECT/CT was 7.4% (McNemar, P < 0.0001) in HNPGL. Overall, [68Ga]Ga-DOTA-TOC PET identified 29 lesions and anatomical imaging identified 27 lesions. [18F]FDOPA PET identified 18 lesions, whereas planar [123I]MIBG imaging identified 1 lesion and SPECT/CT 2 lesions. Conclusion[68Ga]Ga-DOTA-TOC PET/CT is superior for imaging, non-malignant and metastatic HNPGL compared to [18F]FDOPA PET/CT and planar [123I]MIBG imaging, including SPECT/CT, particularly in bone lesions. Combined functional/anatomical imaging ([68Ga]Ga-DOTA-TOC PET/CT) enables excellent delineation of tumour extent in these rare tumour entities. Compared to [123I]MIBG scintigraphy, [68Ga]Ga-DOTA-TOC PET appears far more useful for planning radionuclide therapy in patients with surgically inoperable tumours or metastatic disease.