Results 1 - 10 of 172

The Photometry of Undersampled Point Spread Functions

by Tod Lauer National, Tod R. Lauer
"... An undersampled point spread function may interact with the microstructure of a solid-state detector such that the total flux detected can depend sensitively on where the PSF center falls within a pixel. Such intra-pixel sensitivity variations will not be corrected by flat field calibration and may ..."
Abstract - Cited by 4 (0 self) - Add to MetaCart
An undersampled point spread function may interact with the microstructure of a solid-state detector such that the total flux detected can depend sensitively on where the PSF center falls within a pixel. Such intra-pixel sensitivity variations will not be corrected by flat field calibration and may

Buvat I. Fully 3D Monte Carlo reconstruction in SPECT: a feasibility study. Phys Med Biol

by D Lazaro, Z El Bitar, V Breton, D Hill, I Buvat , 2005
"... In single photon emission computed tomography (SPECT) with parallel hole collimation, image reconstruction is usually performed as a set of bidimensional (2D) analytical or iterative reconstructions. This approach ignores the tridimensional (3D) nature of scatter and detector response function that ..."
Abstract - Cited by 10 (1 self) - Add to MetaCart
In single photon emission computed tomography (SPECT) with parallel hole collimation, image reconstruction is usually performed as a set of bidimensional (2D) analytical or iterative reconstructions. This approach ignores the tridimensional (3D) nature of scatter and detector response function

A Postprocessing Method for Compensation of Scatter and Collimator Blurring in SPECT: A Proof-of-Concept Study A POSTPROCESSING METHOD IN SPECT • Yan and Zeng 83

by Yan Yan , Gengsheng Lawrence Zeng , Yan Yan , Eccls Hlth , Sci Lib , 2009
"... Attenuation, scatter, and blurring are 3 major contributors to SPECT image degradation. Image reconstruction without compensation for these degradations results in reduced contrast and reduced quantitative accuracy. In this proof-of-concept study, we present an efficient postprocessing method to co ..."
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to compensate for the scatter and blurring effect in SPECT. Methods: A raw image is first reconstructed with attenuation correction only. Then, a 2-dimensional (2D) point spread function (PSF) in the image domain is estimated to model the scatter and blurring. This spatially variant 2D PSF is fitted

ITERATIVE CORRECTION FOR SPECT IMAGE DISTORTED BY COLLIMATOR’S CHARACTERISTIC

by Nam-yong Lee
"... The projection data of the emission activity of interests is blurred by the point response function of the collimator that is used to define the range of directions where photons can be detected. The point response function of the collimator is not spatially invariant, but it depends on the distance ..."
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The projection data of the emission activity of interests is blurred by the point response function of the collimator that is used to define the range of directions where photons can be detected. The point response function of the collimator is not spatially invariant, but it depends

Submitted to the P. A. S. P. The Photometry of Undersampled Point Spread Functions

by Tod R. Lauer , 1999
"... An undersampled point spread function may interact with the microstructure of a solid-state detector such that the total flux detected can depend sensitively on where the PSF center falls within a pixel. Such intra-pixel sensitivity variations will not be corrected by flat field calibration and may ..."
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An undersampled point spread function may interact with the microstructure of a solid-state detector such that the total flux detected can depend sensitively on where the PSF center falls within a pixel. Such intra-pixel sensitivity variations will not be corrected by flat field calibration and may

Implementation of Sensitivity and Resolution Modeling for SPECT with Cone-Beam Collimator

by A. Krol *a, V. R. Kunniyur B, W. Lee A, K. R. Gangal B, I. L. Coman C, E. D. Lipson D, D. A. Karczewski A, F. D. Thomas A, D. H. Feiglin A
"... We implemented a fully-3D ordered subsets expectation maximization (OSEM) algorithm with compensation of attenuation, distance-dependent blurring (DDB) and sensitivity modeling for SPECT performed with cone-beam collimator (CBC). The experimentally obtained detector response to point sources across ..."
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We implemented a fully-3D ordered subsets expectation maximization (OSEM) algorithm with compensation of attenuation, distance-dependent blurring (DDB) and sensitivity modeling for SPECT performed with cone-beam collimator (CBC). The experimentally obtained detector response to point sources across

Fully 3D Monte Carlo reconstruction in SPECT: proof of concept and is it worthwhile? 1 Abstract—In Single Photon Emission Computed Tomography

by unknown authors
"... (SPECT) with parallel hole collimation, image reconstruction is usually performed as a set of 2D analytical or iterative reconstructions. This approach ignores the 3D nature of scatter and detector response function that affect the detected signal. To deal with the 3D nature of the image formation p ..."
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(SPECT) with parallel hole collimation, image reconstruction is usually performed as a set of 2D analytical or iterative reconstructions. This approach ignores the 3D nature of scatter and detector response function that affect the detected signal. To deal with the 3D nature of the image formation

SPECT imaging: the spatial distribution of detected photons about a point source in a scatter medium

by T Van Doom, Z Zhang, M Zec
"... When photon scattering around a point source in a scatter medium is considered in isolation, the distribution of the scattering sites is radially symmetric and exponentially decreasing in frequency. Discontinuities in the scattering medium will cause a disruption in this radial symmetry. However, wh ..."
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, when the limited intrinsic energy resolution of the gamma camera, the energy acceptance window and the collimator response are included in the consideration, the distribution of the scattering sites of photons accepted by the gamma camera is complex. Monte Carlo techniques (EGS4) have been used

Improved 3-D correction for partial volume effects

by Laurent Itti, Linda Chang, Thomas Ernst, Fred Mishkin - in brain SPECT. Hum Brain Map , 1997
"... Abstract: An improved method for correction of partial volume effects (PVE) in brain SPECT is proposed. It is fully three-dimensional, does not require particular patient positioning, and works with scans only partially covering the brain. The location of functionally inactive brain regions (primari ..."
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the measured SPECT point spread function; 2) correcting the functional measures according to these ratios; 3) fusing functional and anatomical information at the resolution of MRI. Quantitative validation was performed using a phantom containing a test region in which multiple parallel acrylic plates thinner

SYSTEM MATRIX COMPUTATION FOR ITERATIVE RECONSTRUCTION ALGORITHMS IN SPECT BASED ON DIRECT MEASUREMENTS

by Damian Borys, Katarzyna Szczucka-borys, Kamil Gorczewski
"... A method for system matrix calculation in the case of iterative reconstruction algorithms in SPECT was implemented and tested. Due to a complex mathematical description of the geometry of the detector set-up, we developed a method for system matrix computation that is based on direct measurements of ..."
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analysis of SPECT images. It is also especially important in non-hybrid gamma cameras, where not all physical processes that disturb image acquisition can be easily corrected. Two experiments with an 131 I point source placed at different distances from the detector plane were performed allowing
Results 1 - 10 of 172