This study aimed to compare the clinical utility of [<sup>68</sup>Ga]Ga-PSMA-11 PET/CT with that of 2-[<sup>18</sup>F]fluoro-2-deoxy-D-glucose ([<sup>18</sup>F]FDG) PET/CT in MTC patients, assess PSMA expression by immunohistochemistry, and correlate PSMA expression with [<sup>68</sup>Ga]Ga-PSMA-11 PET/CT findings.<h4>Methods</h4>Twelve patients with MTC who had undergone total thyroidectomy and presented with elevated serum calcitonin and/or carcinoembryonic antigen levels underwent prospective evaluation with [<sup>68</sup>Ga]Ga-PSMA-11 and [<sup>18</sup>F]FDG PET/CT. The gene discussed is CEACAM5; the disease is medullary thyroid gland carcinoma.