Background: (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) scanning is a widely accepted preoperative tumor imaging modality. Herein, we evaluate the becquerel (Bq) as a potential novel quantitative PET measure for application of surgical specimen imaging.
Methods: Retrospectively, PET-avid lesions that could be followed from preoperative imaging, confidently identified in the operating room, imaged ex vivo, and correlated with histopathology were included in this study. Bq counts from both in vivo (preoperative) and ex vivo (surgical specimen) PET/CT images were measured and correlated with histopathology.
Results: Fifty-five PET-avid lesions in 37 patients were included. Forty-six of 55 PET-avid lesions identified were found to contain malignancy on histopathology. Mean Bq counts for the PET-avid lesions were significantly higher that the adjacent PET-nonavid areas (background) within both in vivo and ex vivo imaging (P < .001 and P < .001, respectively). When analyzing all 55 lesions, we found significant increases in Bq levels. PET-avid lesions from in vivo to ex vivo images (P < .001) without significant increases in Bq levels in PET-nonavid lesions from in vivo to ex vivo images (P = .06). When comparing Bq levels between the 2 groups (malignant and benign), we found significantly higher Bq counts in the malignant group on in vivo imaging (P = .02) as well as significantly lower Bq counts in FDG-nonavid areas on ex vivo imaging (P = .04) within the malignant group. Significant differences in PET-avid to PET-nonavid Becquerels ratios within both in vivo and ex vivo images (P = .004, P = .002 respectively) were found, with ex vivo ratio being significantly higher (P < .001).
Conclusions: (18)F-FDG PET/CT imaging using Bqs is the potential to discern malignant lesions from benign tissues within both in vivo and ex vivo scans.