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Proceedings Paper

A helical cone-beam filtered backprojection (CB-FBP) reconstruction algorithm using 3D view weighting
Author(s): Xiangyang Tang; Jiang Hsieh; Roy A. Nilsen; Sandeep Dutta
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Paper Abstract

Although they are approximate only from the theoretical point of view, the FDK cone beam filtered backprojection (CB-FBP) reconstruction algorithm for a circular source trajectory and the general CB-FBP algorithm for other source trajectories, including a helix, have been utilized for decades in extensive applications. A common feature of these two algorithms is that the filtering operation is carried out along each horizontal detector row. Although the horizontal filtering works well for small cone angles, it has been shown that, in applications where a helical source trajectory is employed, the filtering step needs to be carried out along a direction tangential to the source helix to improve reconstruction accuracy. Furthermore, view weighting techniques have to be applied in helical CB-FBP algorithm to suppress streak artifacts caused by data inconsistency. Usually, the view weighting techniques are directly borrowed from their fan beam counterparts, which work well at relatively low helical pitch, but fail at high helical pitches. In this paper, we propose a new helical CB-FBP reconstruction algorithm. The filtering in the proposed algorithm is naturally carried out along the tangential direction of the helical source trajectory after a row-wise fan-to-parallel rebinning. A 3D weighting function (which is dependent on view angle β, ray distance t from the ISO, and cone angle α), is utilized to: (a) suppress artifact caused by data inconsistency; (b) improve noise characteristics by using redundant projection data; (c) extend field of view (FOV) at high pitches by maintaining data redundancy. Both computer simulations and real phantom scans are used to evaluate the proposed helical CB-FBP algorithm. Experimental evaluation verifies that the proposed algorithm produces excellent results from the perspective of reconstruction accuracy, noise characteristics, large FOV at high pitches, and temporal resolution.

Paper Details

Date Published: 26 October 2004
PDF: 11 pages
Proc. SPIE 5535, Developments in X-Ray Tomography IV, (26 October 2004); doi: 10.1117/12.560141
Show Author Affiliations
Xiangyang Tang, GE Healthcare (United States)
Jiang Hsieh, GE Healthcare (United States)
Roy A. Nilsen, GE Healthcare (United States)
Sandeep Dutta, GE Healthcare (United States)

Published in SPIE Proceedings Vol. 5535:
Developments in X-Ray Tomography IV
Ulrich Bonse, Editor(s)

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