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Proceedings Paper

Local convolution-deconvolution for resolution restoration and recovery in PET: a feasibility study
Author(s): Sharok Kimiaei; Refaat Al-Mazrou; Omer Demirkaya
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Paper Abstract

Positron Emission Tomography (PET) is one of the most popular methods for accurate localization and quantification of in vivo concentration of radioactivity. However, in most circular PET scanners, the inherent detector geometry results in a distance dependent and variant point spread function (PSF) in the image plane. Off-centered point sources are imaged with impaired spatial resolution in the radial direction resultng in elliptically shaped points. While some attempts have been made to correct for this unwanted image deterioration through incorporation of the variant detector blurring in the iterative reconstruction procedures, in most cases this effect has been disregarded and the images are uncorrected. In this paper we present and evaluate, by means of computer simulation, a novel approach for correction of the distance dependent and spatially variant point spread function in a two-step procedure. The projections are first homogenized through a non-linear convolution schema prior to reconstruction. In the second step, in order to compensate for the convolution performed in the first step, the spatially shift invariant images thus obtained are deconvolved using a conventional deconvolution method. The preliminary results show that the homogenization can completely remove the shift variant non-isotropic blurring in the image plane. Resolution of the images deconvolved with Lucy-Richardson deconvolution method was improved from 9 mm to 3 mm with maintained shift-invariance.

Paper Details

Date Published: 5 June 2003
PDF: 10 pages
Proc. SPIE 5030, Medical Imaging 2003: Physics of Medical Imaging, (5 June 2003); doi: 10.1117/12.480152
Show Author Affiliations
Sharok Kimiaei, King Faisal Specialist Hospital and Research Ctr. (Saudi Arabia)
Karolinska Institute/Univ. of Stockholm (Sweden)
Refaat Al-Mazrou, King Faisal Specialist Hospital and Research Ctr. (Saudi Arabia)
Omer Demirkaya, King Faisal Specialist Hospital and Research Ctr. (Saudi Arabia)

Published in SPIE Proceedings Vol. 5030:
Medical Imaging 2003: Physics of Medical Imaging
Martin J. Yaffe; Larry E. Antonuk, Editor(s)

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