Value of <sup>68</sup>Ga-DOTATOC and Carbidopa-Assisted <sup>18</sup>F-DOPA PET/CT for Insulinoma Localization
Alessio Impériale, Caroline Boursier, Nicolas Sahakian, Éric Ouvrard, Elodie Chevalier, F. Sébag, Pietro Addeo, David Taïeb
Abstract
To assess the value of <sup>68</sup>Ga-DOTATOC and carbidopa-assisted <sup>18</sup>F-DOPA in 21 hypoglycaemic patients. <b>Methods:</b> All patients who underwent <sup>68</sup>Ga-DOTATOC and/or carbidopa-assisted <sup>18</sup>F-DOPA PET/CT for suspicion of insulinoma from January 2019 to January 2021 were retrospectively analysed. Insulinoma final diagnosis was defined according to pathological reports or consensus. <b>Results:</b> During the study period, 21 patients underwent both <sup>68</sup>Ga-DOTATOC and <sup>18</sup>F-DOPA PET/CT. A final diagnosis of insulin-secreting tumour was reached in 12 cases, including 11 insulinomas and 1 small mixed neuroendocrine/non-neuroendocrine neoplasm. <sup>18</sup>F-DOPA and <sup>68</sup>Ga-DOTATOC PET/CT were positive in 5 (45%) and 7 (64%) of 11 cases, respectively, with 4 concordant positive findings. Moreover, 1 insulinoma was visualized exclusively by <sup>18</sup>F-DOPA PET/CT and 3 by <sup>68</sup>Ga-DOTATOC PET/CT only. <sup>18</sup>F-DOPA and <sup>68</sup>Ga-DOTATOC PET/CT were falsely positive in 1 non-functioning pancreatic neuroendocrine tumour. <b>Conclusion:</b> When <sup>68</sup>Ga-exendin-4 is not available, <sup>68</sup>Ga-SSTR PET/CT should be the first choice for insulinoma functional imaging.