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Proceedings Paper

Incorporating known information into image reconstruction algorithms for transmission tomography
Author(s): Ryan Murphy; Joseph A. O'Sullivan; Jasenka Benac; Donald L. Snyder; Bruce R. Whiting; David G. Politte; Jeffrey F. Williamson
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Paper Abstract

We propose an alternating minimization (AM) image estimation algorithm for iteratively reconstructing transmission tomography images. The algorithm is based on a model that accounts for much of the underlying physics, including Poisson noise in the measured data, beam hardening of polyenergetic radiation, energy dependence of the attenuation coefficients and scatter. It is well-known that these nonlinear phenomena can cause severe artifacts throughout the image when high-density objects are present in soft tissue, especially when using the conventional technique of filtered back projection (FBP). If we assume no prior knowledge of the high-density object(s), our proposed algorithm yields much improved images in comparison to FBP, but retains significant streaking between the high-density regions. When we incorporate the knowledge of the attenuation and pose parameters of the high-density objects into the algorithm, our simulations yield images with greatly reduced artifacts. To accomplish this, we adapted the algorithm to perform a search at each iteration (or after every n iterations) to find the optimal pose of the object before updating the image. The final iteration returns pose values within 0.1 millimeters and 0.01 degrees of the actual location of the high-density structures.

Paper Details

Date Published: 9 May 2002
PDF: 9 pages
Proc. SPIE 4684, Medical Imaging 2002: Image Processing, (9 May 2002); doi: 10.1117/12.467179
Show Author Affiliations
Ryan Murphy, Washington Univ. (United States)
Joseph A. O'Sullivan, Washington Univ. (United States)
Jasenka Benac, Washington Univ. (United States)
Donald L. Snyder, Washington Univ. (United States)
Bruce R. Whiting, Mallinckrodt Institute of Radiology/Washington Univ. (United States)
David G. Politte, Mallinckrodt Institute of Radiology/Washington Univ. (United States)
Jeffrey F. Williamson, Mallinckrodt Institute of Radiology/Washington Univ. (United States)

Published in SPIE Proceedings Vol. 4684:
Medical Imaging 2002: Image Processing
Milan Sonka; J. Michael Fitzpatrick, Editor(s)

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