Implementation of an iterative scatter correction, the influence of attenuation map quality and their effect on absolute quantitation in SPECT.

Full Abstract

We investigated the accuracy of qSPECT, a quantitative SPECT reconstruction algorithm we have developed which employs corrections for collimator blurring, photon attenuation and scatter, and provides images in units of absolute radiotracer concentrations (kBq cm(-3)). Using simulated and experimental phantom data with characteristics similar to clinical cardiac perfusion data, we studied the implementation of a scatter correction (SC) as part of an iterative reconstruction protocol. Additionally, with experimental phantom studies we examined the influence of CT-based attenuation maps, relative to those obtained from conventional SPECT transmission scans, on SCs and quantitation. Our results indicate that the qSPECT estimated scatter corrections did not change appreciably after the third iteration of the reconstruction. For the simulated data, qSPECT concentrations agreed with images reconstructed using ideal, scatter-free, simulated data to within 6%. For the experimental data, we observed small systematic differences in the scatter fractions for data using different combinations of SCs and attenuation maps. The SCs were found to be significantly influenced by errors in image coregistration. The reconstructed concentrations using CT-based corrections were more quantitatively accurate than those using attenuation maps from conventional SPECT transmission scans. However, segmenting the attenuation maps from SPECT transmission scans could provide sufficient accuracy for most applications.

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Author information

Author/s: Vandervoort, Eric (E); Celler, Anna (A); Harrop, Ronald (R);

Affiliation: Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, V6T 1Z1, Canada. evander(-atsign-)physics.ubc.ca

Journal and publication information

Publication Type: Evaluation Studies; Journal Article

Journal: Physics in medicine and biology (Phys Med Biol), published in England. (Language: eng)

Reference: 2007-Mar; vol 52 (issue 5) : pp 1527-45

Dates: Created 2007/02/15; Completed 2007/04/24;

PMID: 17301469, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Algorithms
Artifacts
Image Enhancement - methods
Image Interpretation, Computer-Assisted - methods
Phantoms, Imaging

Phantoms, Imaging
Reproducibility of Results
Scattering, Radiation
Sensitivity and Specificity
Tomography, Emission-Computed, Single-Photon - instrumentation; methods

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