title: Implementation of an accelerated iterative algorithm for cone-beam SPECT.
abstract: In this paper we describe the implementation of an accelerated iterative reconstruction algorithm (AIRA) for cone-beam (CB) projections using a single circular orbit in single-photon-emission computed tomography (SPECT). This algorithm is a modified maximum-likelihood-expectation-maximization (ML-EM) algorithm and several approaches have been used to accelerate the reconstruction process. These approaches include: (i) the use of ordered subsets; (ii) the use of active areas and volumes; and (iii) the storing in memory of the transition vector for a given ray (during the forward projection step). This algorithm, which compensates for collimator geometric sensitivity variation as a function of position and makes uniform attenuation corrections has been evaluated using experimentally acquired phantom data. The results demonstrate a two-orders-of-magnitude decrease of the computational time of this algorithm over the conventional ML-EM algorithm with similar convergence properties.
authors.affiliation: Department of Radiology, PO Box 3949, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: R J
authors.initials: RJ
authors.lastname: Jaszczak
authors.forename: K L
authors.initials: KL
authors.lastname: Greer
authors.forename: R E
authors.initials: RE
authors.lastname: Coleman
mesh_terms: D000465:Algorithms; D016477:Artifacts; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D016013:Likelihood Functions; D015233:Models, Statistical; D019047:Phantoms, Imaging; D017785:Photons; D012680:Sensitivity and Specificity; D012984:Software; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*