Consistency condition and ML-EM checkerboard artifacts

Jiangsheng You, Jing Wang, Zhengrong Liang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The expectation maximization (EM) algorithm for the maximum likelihood (ML) image reconstruction criterion generates severe checkerboard artifacts in the presence of noise. A classical remedy is to impose an a priori constraint for a penalized ML or maximum a posteriori probability solution. The penalty reduces the checkerboard artifacts and also introduces uncertainty because a priori information is usually unknown in clinic. Recent theoretical investigation reveals that the noise can be divided into two components. One is called null-space noise which annihilates during filtered backprojection (FBP)-type analytical image reconstruction. The other is called range-space noise which propagates into the FBP-type analytically reconstructed image. In particular, the null-space noise can be numerically estimated. The aim of this work is to investigate the relation between the null-space noise and the checkerboard artifacts in the ML-EM image reconstruction from noise projection data. It is expected that removing the null-space noise from the projection data could improve the signal-to-noise ratio of the data and, therefore, reduce the checkerboard artifacts in the ML-EM reconstructed images. The expectation was realized by computer simulation studies with application to single photon emission computed tomography, where the noise has been a major factor for image degradation. The reduction of the ML-EM checkerboard artifacts by removing the null-space noise avoids the uncertainty of using a priori penalty.

Original languageEnglish (US)
Title of host publication2006 IEEE Nuclear Science Symposium - Conference Record
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages2245-2250
Number of pages6
ISBN (Print)1424405610, 9781424405619
DOIs
StatePublished - Jan 1 2006
Event2006 IEEE Nuclear Science Symposium, Medical Imaging Conference and 15th International Workshop on Room-Temperature Semiconductor X- and Gamma-Ray Detectors, Special Focus Workshops, NSS/MIC/RTSD - San Diego, CA, United States
Duration: Oct 29 2006Nov 4 2006

Publication series

NameIEEE Nuclear Science Symposium Conference Record
Volume4
ISSN (Print)1095-7863

Other

Other2006 IEEE Nuclear Science Symposium, Medical Imaging Conference and 15th International Workshop on Room-Temperature Semiconductor X- and Gamma-Ray Detectors, Special Focus Workshops, NSS/MIC/RTSD
CountryUnited States
CitySan Diego, CA
Period10/29/0611/4/06

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging

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