%0 Journal Article %T Quantitative evaluation of TOF benefits indifferent tumor regions of Overweight patients in clinical PET/CT scanner %J Iranian Journal of Medical Physics %I Mashhad University of Medical Sciences %Z 2345-3672 %A Jozi, Hanieh Sadat %A Ghafarian, Pardis %D 2018 %\ 12/01/2018 %V 15 %N Special Issue-12th. Iranian Congress of Medical Physics %P 84-84 %! Quantitative evaluation of TOF benefits indifferent tumor regions of Overweight patients in clinical PET/CT scanner %K F18-FDG-PET/CT %K 𝑆𝑈𝑉𝑚𝑎𝑥 %K TOF %K Overweight %K Tumor-to-background ratio %R 10.22038/ijmp.2018.12362 %X Introduction: Using TOF information in image reconstruction reduce the noise propagation along the LOR during forward and back projection of the data, and improve the image signal-to-noise ratio (SNR) of PET scanners. This improvement is dependent on the scintillator decay time, time response of coincidence circuits and front-end electronics. The goals of this study were to evaluate the benefits of time of flight (TOF) in clinical PET/CT images of overweight patients in relation to the tumor-to-background ratios, and to determine what SNR gains in PET performance could be achieved. Materials and Methods: 32 overweight patient studies with normal 18F-fluoro-deoxyglucose (18F-FDG) uptake were chosen. FDG-PET/CT imaging was performed on the LYSO-based PET component of Discovery RX PET/CT scanner. Various tumor sizes in different locations of the thorax and abdomen in PET images have been investigated. The PET data were reconstructed with the baseline ordered-subsets expectation maximization (OSEM) algorithm+ PSF model and OSEM + PSF + TOF model. The image quality was evaluated using AMIDE to estimate the SNR, contrast, coefficient of variation(COV), and the standardized uptake values (𝑆𝑈𝑉𝑚𝑎𝑥). The results were then subjectively analyzed as a function of patient body-mass index (25