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Absolute quantitative total-body small-animal SPECT with focusing pinholes

PURPOSE: In pinhole SPECT, attenuation of the photon flux on trajectories between source and pinholes affects quantitative accuracy of reconstructed images. Previously we introduced iterative methods that compensate for image degrading effects of detector and pinhole blurring, pinhole sensitivity an...

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Autores principales: Wu, Chao, van der Have, Frans, Vastenhouw, Brendan, Dierckx, Rudi A. J. O., Paans, Anne M. J., Beekman, Freek J.
Formato: Texto
Lenguaje:English
Publicado: Springer-Verlag 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948163/
https://www.ncbi.nlm.nih.gov/pubmed/20577738
http://dx.doi.org/10.1007/s00259-010-1519-9
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author Wu, Chao
van der Have, Frans
Vastenhouw, Brendan
Dierckx, Rudi A. J. O.
Paans, Anne M. J.
Beekman, Freek J.
author_facet Wu, Chao
van der Have, Frans
Vastenhouw, Brendan
Dierckx, Rudi A. J. O.
Paans, Anne M. J.
Beekman, Freek J.
author_sort Wu, Chao
collection PubMed
description PURPOSE: In pinhole SPECT, attenuation of the photon flux on trajectories between source and pinholes affects quantitative accuracy of reconstructed images. Previously we introduced iterative methods that compensate for image degrading effects of detector and pinhole blurring, pinhole sensitivity and scatter for multi-pinhole SPECT. The aim of this paper is (1) to investigate the accuracy of the Chang algorithm in rodents and (2) to present a practical Chang-based method using body outline contours obtained with optical cameras. METHODS: Here we develop and experimentally validate a practical method for attenuation correction based on a Chang first-order method. This approach has the advantage that it is employed after, and therefore independently from, iterative reconstruction. Therefore, no new system matrix has to be calculated for each specific animal. Experiments with phantoms and animals were performed with a high-resolution focusing multi-pinhole SPECT system (U-SPECT-II, MILabs, The Netherlands). This SPECT system provides three additional optical camera images of the animal for each SPECT scan from which the animal contour can be estimated. RESULTS: Phantom experiments demonstrated that an average quantification error of –18.7% was reduced to –1.7% when both window-based scatter correction and Chang correction based on the body outline from optical images were applied. Without scatter and attenuation correction, quantification errors in a sacrificed rat containing sources with known activity ranged from –23.6 to –9.3%. These errors were reduced to values between –6.3 and +4.3% (with an average magnitude of 2.1%) after applying scatter and Chang attenuation correction. CONCLUSION: We conclude that the modified Chang correction based on body contour combined with window-based scatter correction is a practical method for obtaining small-animal SPECT images with high quantitative accuracy.
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spelling pubmed-29481632010-10-20 Absolute quantitative total-body small-animal SPECT with focusing pinholes Wu, Chao van der Have, Frans Vastenhouw, Brendan Dierckx, Rudi A. J. O. Paans, Anne M. J. Beekman, Freek J. Eur J Nucl Med Mol Imaging Original Article PURPOSE: In pinhole SPECT, attenuation of the photon flux on trajectories between source and pinholes affects quantitative accuracy of reconstructed images. Previously we introduced iterative methods that compensate for image degrading effects of detector and pinhole blurring, pinhole sensitivity and scatter for multi-pinhole SPECT. The aim of this paper is (1) to investigate the accuracy of the Chang algorithm in rodents and (2) to present a practical Chang-based method using body outline contours obtained with optical cameras. METHODS: Here we develop and experimentally validate a practical method for attenuation correction based on a Chang first-order method. This approach has the advantage that it is employed after, and therefore independently from, iterative reconstruction. Therefore, no new system matrix has to be calculated for each specific animal. Experiments with phantoms and animals were performed with a high-resolution focusing multi-pinhole SPECT system (U-SPECT-II, MILabs, The Netherlands). This SPECT system provides three additional optical camera images of the animal for each SPECT scan from which the animal contour can be estimated. RESULTS: Phantom experiments demonstrated that an average quantification error of –18.7% was reduced to –1.7% when both window-based scatter correction and Chang correction based on the body outline from optical images were applied. Without scatter and attenuation correction, quantification errors in a sacrificed rat containing sources with known activity ranged from –23.6 to –9.3%. These errors were reduced to values between –6.3 and +4.3% (with an average magnitude of 2.1%) after applying scatter and Chang attenuation correction. CONCLUSION: We conclude that the modified Chang correction based on body contour combined with window-based scatter correction is a practical method for obtaining small-animal SPECT images with high quantitative accuracy. Springer-Verlag 2010-06-25 2010 /pmc/articles/PMC2948163/ /pubmed/20577738 http://dx.doi.org/10.1007/s00259-010-1519-9 Text en © The Author(s) 2010 https://creativecommons.org/licenses/by-nc/4.0/ This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
spellingShingle Original Article
Wu, Chao
van der Have, Frans
Vastenhouw, Brendan
Dierckx, Rudi A. J. O.
Paans, Anne M. J.
Beekman, Freek J.
Absolute quantitative total-body small-animal SPECT with focusing pinholes
title Absolute quantitative total-body small-animal SPECT with focusing pinholes
title_full Absolute quantitative total-body small-animal SPECT with focusing pinholes
title_fullStr Absolute quantitative total-body small-animal SPECT with focusing pinholes
title_full_unstemmed Absolute quantitative total-body small-animal SPECT with focusing pinholes
title_short Absolute quantitative total-body small-animal SPECT with focusing pinholes
title_sort absolute quantitative total-body small-animal spect with focusing pinholes
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948163/
https://www.ncbi.nlm.nih.gov/pubmed/20577738
http://dx.doi.org/10.1007/s00259-010-1519-9
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