Title :
Projector model for efficient list-mode reconstruction in PET scanners with parallel planar detectors
Author :
Ortuno, J.E. ; Sportelli, Giancarlo ; Guerra, Pedro ; Santos, Andres
Author_Institution :
Dipt. de Ing. Electron., Univ. Politec. de Madrid, Madrid, Spain
Abstract :
We have developed a new projector model specifically tailored for fast list-mode tomographic reconstructions in Positron emission tomography (PET) scanners with parallel planar detectors. The model provides an accurate estimation of the probability distribution of coincidence events defined by pairs of scintillating crystals. This distribution is parameterized with 2D elliptical Gaussian functions defined in planes perpendicular to the main axis of the tube of response (TOR). The parameters of these Gaussian functions have been obtained by fitting Monte Carlo simulations that include positron range, acolinearity of gamma rays, as well as detector attenuation and scatter effects. The proposed model has been applied efficiently to list-mode reconstruction algorithms. Evaluation with Monte Carlo simulations over a rotating high resolution PET scanner indicates that this model allows to obtain better recovery to noise ratio in OSEM (ordered-subsets, expectation-maximization) reconstruction, if compared to list-mode reconstruction with symmetric circular Gaussian TOR model, and histogram-based OSEM with precalculated system matrix using Monte Carlo simulated models and symmetries.
Keywords :
Monte Carlo methods; expectation-maximisation algorithm; image reconstruction; medical image processing; positron emission tomography; probability; solid scintillation detectors; tomography; 2D elliptical Gaussian functions; Gaussian function parameters; Monte Carlo simulations; OSEM reconstruction; PET scanners; and histogram based OSEM; coincidence event probability distribution; efficient list mode reconstruction; fast list mode tomographic reconstructions; gamma ray acolinearity; high resolution PET scanner; ordered subsets expectation maximization reconstruction; parallel planar detectors; positron emission tomography; positron range; projector model; response tube main axis; scintillating crystal pairs; symmetric circular Gaussian TOR model; system matrix; Biological system modeling; Biomedical imaging; Kernel; Logic gates; Noise; Noise measurement;
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2011 IEEE
Conference_Location :
Valencia
Print_ISBN :
978-1-4673-0118-3
DOI :
10.1109/NSSMIC.2011.6153800