Fast Methods for Approximation of Resolution and Covariance for SPECT

J. Webster Stayman, Jeffrey A. Fessler

Research output: Contribution to conferencePaperpeer-review

8 Scopus citations


Resolution and covariance predictors have been derived previously for penalized-likelihood estimators. These predictors can provide accurate approximations to the local resolution properties and covariance functions for tomographic systems given a good estimate of the mean measurements. However, when numerous evaluations are made repeatedly (as in penalty design or calculation of variance images), these predictors still require large amounts of computing time. In [1], we discussed methods for precomputing a large portion of the predictor for shift-invariant system geometries. In this paper, we generalize the efficient procedure discussed in [1] to shift-variant single photon emission computed tomography (SPECT) systems. This generalization relies on a new attenuation approximation and several observations on the symmetries in SPECT systems. These new general procedures apply to both 2D and fully-3D SPECT models, that may be either precomputed and stored, or written in procedural form.

Original languageEnglish (US)
Number of pages3
StatePublished - 2002
Externally publishedYes
Event2002 IEEE Nuclear Science Symposium Conference Record - Norfolk, VA, United States
Duration: Nov 10 2002Nov 16 2002


Other2002 IEEE Nuclear Science Symposium Conference Record
Country/TerritoryUnited States
CityNorfolk, VA


  • Image quality
  • Local impulse response
  • Noise
  • Tomography
  • Variance

ASJC Scopus subject areas

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


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