Spatial resolution properties of FB and ML-EM reconstruction methods

D. W. Wilson, B. M.W. Tsui

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

Abstract

We investigated the spatial resolution and quantitative properties of SPECT images reconstructed using filtered-backprojection (FB) and maximum likelihood-expectation maximization (ML-EM) algorithms. We studied ML-EM as a function of iteration number and projector/backprojector (p/bp) model, and FB as a function of filter. To quantify the image resolution for a shift-variant process we defined a local point response function (PRF). To justify the use of the local PRF to quantify resolution for nonlinear ML-EM we tested the regime over which the algorithm behaved linearly with respect to input perturbations. Using Fourier domain analogs of the local PRF we demonstrated that ML-EM with an accurate p/bp can lead to images of better resolution than FB with a Butterworth or Metz filter or ML-EM with a p/bp that does not fully model the imaging process. We also showed that the resolution improves with increasing ML-EM iteration number, and the extent of the improvement depends on the accuracy of the p/bp model. We conclude that the local PRF can be used to characterize spatial resolution in SPECT images, and that ML-EM offers the possibility of superior resolution, particularly if the algorithm contains a good model of the imaging process.

Original languageEnglish (US)
Title of host publicationIEEE Nuclear Science Symposium & Medical Imaging Conference
PublisherPubl by IEEE
Pages1189-1193
Number of pages5
Editionpt 2
ISBN (Print)0780314875
StatePublished - 1994
Externally publishedYes
EventProceedings of the 1993 IEEE Nuclear Science Symposium & Medical Imaging Conference - San Francisco, CA, USA
Duration: Oct 30 1993Nov 6 1993

Publication series

NameIEEE Nuclear Science Symposium & Medical Imaging Conference
Numberpt 2

Other

OtherProceedings of the 1993 IEEE Nuclear Science Symposium & Medical Imaging Conference
CitySan Francisco, CA, USA
Period10/30/9311/6/93

ASJC Scopus subject areas

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

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