Usefulness of respiratory-gated F-18-FDG PET/CT scan protocol in patients having positive myocardial F-18-FDG uptake

摘要

Objective The aim of this study were to estimate the influence of respiratory movement on the fluorine-18-fluorodeoxyglucose (F-18-FDG) PET/computed tomography (CT) imaging of patients having positive myocardial F-18-FDG uptake and to demonstrate an adequate respiratory-gated F-18-FDG PET/CT scan protocol. Materials and methods An anthropomorphic chest phantom containing a cardiac ventricle phantom was filled with an fluorine-18 solution and scanned in both a nonmoving state and a moving state with respiratory gating. In the nonmoving state, PET images were acquired in static mode (static PET), whereas in the moving state, PET images were acquired in a nongated mode (nongated PET), and in a gated mode (gated PET). The gated PET images were divided into 2-10 phases. The standardized uptake value (SUV)(nongated ratio) and SUVgated ratio (SUVnongated ratio or SUVgated ratio=SUVmean of nongated PET or gated PET/SUVmean of static PET) were calculated. In addition, nongated PET images and gated PET images were created from 12 sets of respiratory-gated clinical F-18-FDG PET/CT acquisitions. The clinical 12 gated PET data were divided into 2-8 phases. We measured SUVmax of cardiac volume data at each number of phases. Results In dividing into more than three phases, the SUVgated ratio remarkably improved. In dividing into more than five phases, rate of SUVmax improvement from nongated PET showed 5% in the analysis of clinical data. Conclusion For a F-18-FDG PET/CT scan for patients with having positive myocardial F-18-FDG uptake, a respiratory-gated PET protocol divided into five phases is recommended, to minimize the influence of internal motion on cardiac accumulation.