1. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology The high matrix acquisition technique for imaging of atherosclerotic plaque inflammation in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography with time-of-flight: Phantom study Masaya Suda, PhD Clinical Imaging Center for Healthcare, Nippon Medical School, Tokyo, Japan, Institution Picture/Logo Optional Copyright American Society of Nuclear Cardiology

2. BACKGROUND 1- 18 F-FDG PET have enabled evaluation of inflammation and macrophages in atherosclerotic plaque. 2- Motion artifact caused induced by a moving small target will decrease SNR and reduce count density. 3-The smaller size of target as plaques is limited to the spatial resolution of PET imaging 4- The aim of this study is to investigate the effectiveness of high-resolution PET using the TOF technique for small and moving targets mimicking human atherosclerotic coronary artery plaque in a phantom. Copyright American Society of Nuclear Cardiology Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology

3. METHODS A.Study type:( Select all that apply) phantom study A.Study variables Copyright American Society of Nuclear Cardiology Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology

4. RESULTS Copyright American Society of Nuclear Cardiology Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology TBR as a function of sphere size at each radioactivity concentration.

5. RESULTS Copyright American Society of Nuclear Cardiology Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology non-motion motion φ:4 mm φ:2 mm High matrix with TOF Conven- tional (a) (c) (b) (d) (a) (c) (b) (d) ×8 ×16 ×2 ×4 ×8 ×16 ×2 ×4 Comparison with and without motion: representative images of heart phantom study. Short-axis images of conventional algorithm without TOF and high matrix algorithm with TOF. Left; φ 4 mm, Right; φ 2 mm, Image sets: (a) conventional algorithm without TOF and not in motion; (b) conventional algorithm without TOF and in motion; (c) high matrix algorithm with TOF and not in motion; (d) high matrix algorithm with TOF and in motion

6. CONCLUSIONS 1- Visual detectability, maximum activity, and TBR with the high matrix algorithm with TOF were better than with the conventional algorithm without TOF in microsphere phantom studies. 2- Heart phantom studies demonstrated that Partial volume effect is a factor that can be overridden by cardiac contraction in the detection of atherosclerotic plaques in coronary arteries. Copyright American Society of Nuclear Cardiology Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology