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Proceedings Paper

Implementation of alternating minimization algorithms for fully 3D CT imaging
Author(s): David G. Politte; Shenyu Yan; Joseph A. O'Sullivan; Donald L. Snyder; Bruce R. Whiting
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Paper Abstract

Algorithms based on alternating minimization (AM) have recently been derived for computing maximum-likelihood images in transmission CT, incorporating accurate models of the transmission-imaging process. In this work we report the first fully three-dimensional implementation of these algorithms, intended for use with multi-row detector spiral CT systems. The most demanding portion of the computations, the three-dimensional projections and backprojections, are calculated using a precomputed lookup table containing a discretized version of the point-spread function that maps between the measurement and image spaces. This table accounts for the details of the scanner. A cylindrical phantom with cylindrical and spherical inserts of known attenuation was scanned with a Siemens Sensation 16, which was employed in a rapid, spiral acquisition mode with 16 active detector rows. These data were downsampled and reconstructed using a monoenergetic version of our AM algorithm. The estimated attenuation coefficients closely match the known coefficients for the cylinder and the embedded objects. We are investigating methods for further accelerating these computations by using a combination of techniques that reduce the time of each iteration and that increase the convergence of the log-likelihood from iteration to iteration.

Paper Details

Date Published: 11 March 2005
PDF: 12 pages
Proc. SPIE 5674, Computational Imaging III, (11 March 2005); doi: 10.1117/12.602748
Show Author Affiliations
David G. Politte, Mallinckrodt Institute of Radiology, Washington Univ. (United States)
Shenyu Yan, Washington Univ. (United States)
Joseph A. O'Sullivan, Washington Univ. (United States)
Donald L. Snyder, Washington Univ. (United States)
Bruce R. Whiting, Mallinckrodt Institute of Radiology, Washington Univ. (United States)

Published in SPIE Proceedings Vol. 5674:
Computational Imaging III
Charles A. Bouman; Eric L. Miller, Editor(s)

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