title: An evaluation of maximum likelihood reconstruction for SPECT.
abstract: A reconstruction method for SPECT (single photon emission computerized tomography) that uses the maximum likelihood (ML) criterion and an iterative expectation-maximization (EM) algorithm solution is examined. The method is based on a model that incorporates the physical effects of photon statistics, nonuniform photon attenuation, and a camera-dependent point-spread response function. Reconstructions from simulation experiments are presented which illustrate the ability of the ML algorithm to correct for attenuation and point-spread. Standard filtered backprojection method reconstructions, using experimental and simulated data, are included for reference. Three studies were designed to focus on the effects of noise and point-spread, on the effect of nonuniform attenuation, and on the combined effects of all three. The last study uses a chest phantom and simulates Tl-201 imaging of the myocardium. A quantitative analysis of the reconstructed images is used to support the conclusion that the ML algorithm produces reconstructions that exhibit improved signal-to-noise ratios, improved image resolution, and image quantifiability.
authors.affiliation: Dept. of Electr. Eng., Washington Univ., St. Louis, MO.
authors.forename: E S
authors.initials: ES
authors.lastname: Chornoboy
authors.forename: C J
authors.initials: CJ
authors.lastname: Chen
authors.forename: M I
authors.initials: MI
authors.lastname: Miller
authors.forename: T R
authors.initials: TR
authors.lastname: Miller
authors.forename: D L
authors.initials: DL
authors.lastname: Snyder