Is There Novel 18F-FDG Biodistribution in the Digital PET/CT Era? A Real-World Data Analysis

Background: This retrospective multicenter study investigated the biodistribution of Fluorodeoxyglucose (18F-FDG) in the positron emission tomography (PET)/computed tomography (CT) in digital PET/CT (dPET) compared to analog PET/CT (aPET), focusing differences in physiological uptake in reference and small structures across various scanner models. Materials and Methods: One hundred thirty patients with similar preimaging conditions underwent both dPET and aPET imaging within 6 months. Visual evaluations and paired comparative analyses of semiquantitative parameters were performed for small and reference structures. Results: 18F-FDG uptake was higher in both reference and small structures for dPET compared to three different aPET scanners. The Siemens mCT20-4R (mCT20) demonstrated comparable results to dPET. Notably, mCT20 had higher standardized uptake value (SUVmax) for the conus medullaris (CM) (3.20 vs. 2.76). CM was most highly visible with dPET on visual evaluation by physicians. Conclusions: Digital PET/CT provides higher SUV values in both small and reference structures. This leads to improved visualization of 18F-FDG physiological biodistribution. Given the growing adoption of dPET technology, these advancements should be carefully considered in image interpretation and clinical research.