<sup>68</sup>Ga-PSMA PET/CT Versus <sup>18</sup>F-FDG PET/CT for Imaging of Hepatocellular Carcinoma
Cihan Gündoğan, Nurhan Ergül, Mehmet Semih Çakır, Özgür Kılıçkesmez, Rıza Umar Gürsu, Tamer Aksoy, Tevfik Fikret Çermik
Abstract
Objectives: This study aimed to compare the metabolic parameters obtained from 18 fluorine-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 ( 68 Ga)-prostate-specific membrane antigen (PSMA) PET/CT and investigate the relationship between serum alpha-fetoprotein and PET scan parameters in patients with hepatocellular carcinoma. Methods: Fourteen patients were recruited after dynamic magnetic resonance imaging (MRI) of the upper abdomen, and 18 F-FDG and 68 Ga-PSMA PET/CT imaging studies were conducted. Regions of interest (ROIs) were drawn from lesion-free liver tissue, abdominal aorta (A), and right medial gluteal muscle (G) for the background activity. Maximum standard uptake value (SUV max ) of these regions were compared with the SUV max of primary tumor (T). Results: On visual assessment, five patients (36%) experienced low 18 F-FDG uptake in the primary lesion, three patients (21%) experienced moderate uptake, and six patients (43%) experienced high uptake. However, only one patient (7%) showed low 68 Ga-PSMA uptake, two patients (14%) showed moderate uptake, and 11 patients (79%) showed high uptake. Four patients with a low 18 F-FDG uptake showed high 68 Ga-PSMA uptake, while one patient exhibited low uptake with both 18 F-FDG and 68 Ga-PSMA. The number of lesions on 68 Ga-PSMA PET/CT and MRI was significantly higher than 18 F-FDG PET/CT (p=0.042 and 0.026, respectively). T/A and T/G values were significantly higher in 68 Ga-PSMA than 18 F-FDG (p=0.002 and 0.002, respectively). Conclusion: 68 Ga-PSMA PET/CT is superior to 18 F-FDG PET/CT in the staging of hepatocellular carcinoma. High 68 Ga-PSMA uptake could be promising for PSMA-targeted radionuclide treatments.