title: Improving spatial resolution in SPECT with the combination of PSPMT based detector and iterative reconstruction algorithms.
abstract: This paper investigates the possibility of developing a SPECT system that combines the high spatial resolution of position sensitive photomultiplier tubes (PSPMTs) with the excellent performance of iterative reconstruction algorithms. A small field of view (FOV) camera based on a PSPMT and a pixelized scintillation crystal made of CsI(Tl) have been used for the acquisition of the projections. With the use of maximum likelihood expectation maximization (ML-EM) and ordered subsets expectation maximization (OSEM) slices of the object are obtained while three-dimensional (3D) reconstruction of the object is carried out using a modified marching cubes (MMC) algorithm. The spatial resolution of tomographic images obtained with the system was 2-3mm. The spatial resolution of a conventional system that uses filtered backprojection (FBP) for slices reconstruction was more than 9 mm.
authors.affiliation: Department of Electrical and Computer Engineering, Institute of Communication and Computer Systems, National Technical University of Athens, 9, Iroon Polytechniou Str., Zografos, Attiki, 15773 Athens, Greece. gloudos@central.ntua.gr
authors.forename: G K
authors.initials: GK
authors.lastname: Loudos
authors.forename: K S
authors.initials: KS
authors.lastname: Nikita
authors.forename: N K
authors.initials: NK
authors.lastname: Uzunoglu
authors.forename: N D
authors.initials: ND
authors.lastname: Giokaris
authors.forename: C N
authors.initials: CN
authors.lastname: Papanicolas
authors.forename: S C
authors.initials: SC
authors.lastname: Archimandritis
authors.forename: D
authors.initials: D
authors.lastname: Varvarigou
authors.forename: D
authors.initials: D
authors.lastname: Maintas
mesh_terms: D000465:Algorithms; D015902:Gamma Cameras; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D019047:Phantoms, Imaging; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000379:methods*