Feasibility of Global Assessment of Bone Metastases in Prostate Cancer with F-Sodium Fluoride-PET/Computed Tomography.

18F-sodium fluoride (NaF) PET/computed tomography (CT) allows detection of bone metastases in patients with prostate cancer (PCa). The aim of this study was to test the feasibility of assessing global metastatic bone disease in patients with PCa by using a threshold-based PET segmentation technique. This retrospective analysis was performed in 32 patients with PCa with known bone metastases who underwent NaF-PET/CT imaging. An adaptive contrast-oriented thresholding technique was used to segment NaF avid lesions. The mean metabolic volumetric product (MVPmean), partial volume-corrected MVPmean (cMVPmean), and metabolically active volume (MAV) were calculated. Lesional values were summed within each patient to obtain the global PET disease burden. Pearson correlation analysis was used to assess the associations between global NaF-PET/CT metrics and clinical biomarkers of metastatic disease activity. Global MVPmean, cMVPmean, and MAV were significantly correlated with alkaline phosphatase (ALP) levels (p < 0.05). No correlation was observed between global NaF-PET/CT measures and prostate-specific antigen (PSA) levels. Global assessment is a feasible method to quantify metastatic bone disease activity in patients with PCa. Convergent validity was supported by demonstrating a significant correlation between NaF-PET/CT parameters and blood ALP levels.