title: Statistical image reconstruction for polyenergetic X-ray computed tomography.
abstract: This paper describes a statistical image reconstruction method for X-ray computed tomography (CT) that is based on a physical model that accounts for the polyenergetic X-ray source spectrum and the measurement nonlinearities caused by energy-dependent attenuation. We assume that the object consists of a given number of nonoverlapping materials, such as soft tissue and bone. The attenuation coefficient of each voxel is the product of its unknown density and a known energy-dependent mass attenuation coefficient. We formulate a penalized-likelihood function for this polyenergetic model and develop an ordered-subsets iterative algorithm for estimating the unknown densities in each voxel. The algorithm monotonically decreases the cost function at each iteration when one subset is used. Applying this method to simulated X-ray CT measurements of objects containing both bone and soft tissue yields images with significantly reduced beam hardening artifacts.
authors.affiliation: Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor 48109-2122, USA. ielbakri@umich.edu
authors.forename: Idris A
authors.initials: IA
authors.lastname: Elbakri
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Fessler
mesh_terms: D000465:Algorithms; D001842:Bone and Bones / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D003198:Computer Simulation; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008954:Models, Biological; D015233:Models, Statistical; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*; D014867:Water
chemical_list: D014867:Water