The effects of incorrect modeling on noise and resolution properties of ML-EM images

D. W. Wilson, H. H. Barrett

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The effects of incorrect compensation for collimator blur in single-photon emission computed tomography (SPECT) images are studied in terms of the noise and resolution properties of the reconstructed images. Qualitative analysis of images of the Hoffman brain phantom reconstructed using nonlinear maximum-likelihood-expectation maximization (ML-EM) show the behavior of longer noise correlations for high-pass filtered images. These qualitative observations are confirmed with more quantitative noise measures. The differences also appear in images reconstructed using linear Landweber iteration. However, the signal-to-noise ratio, in terms of the noise-equivalent quanta, remains largely unchanged. We conclude that the compensation model affects SPECT image properties, though the effect on human task performance remains to be studied.

Original languageEnglish (US)
Pages (from-to)768-773
Number of pages6
JournalIEEE Transactions on Nuclear Science
Volume49 I
Issue number3
StatePublished - Jun 2002


  • Image reconstruction
  • Image resolution
  • Image restoration

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Electrical and Electronic Engineering


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