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Proceedings Paper

Effects of digital geometry and phantom size on cone-beam CT point spread function measurement
Author(s): Zikuan Chen; Yang Tao
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Paper Abstract

The three-dimensional point spread function (3D PSF) of cone-beam computed tomography (CBCT) can be measured through the use of point phantom or edge phantom. In cone-beam tomography theory, an input of delta impulse function will produce an output of a delta function (except a scale factor) under the assumption of continuous geometry, thus manifesting spatial shift invariance over the scan field of view (SFOV). For a practical CBCT system, its 3D PSF is of spatial variant distribution over the SFOV, due to the digital geometry in discrete projection detection and gridded volume reconstruction. In principle, the 3D PSF of a CBCT system can be measured either by a micro point-like phantom (<1mm) by approaching a delta impulse function, or by a macro edge phantom (>1mm) by analyzing the edge blurring mechanism. We found that there exists ambiguity and controversy among the 3D PSF measurement and characterization, varying with the size of the phantom. In this work, we will investigate the effects of digital geometry and phantom size on the 3D PSF measurement. In the results, we will propose an experimental protocol for eliminating the uncertainty associated with the 3D PSF characterization of a CBCT system.

Paper Details

Date Published: 19 March 2008
PDF: 11 pages
Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 691350 (19 March 2008); doi: 10.1117/12.765928
Show Author Affiliations
Zikuan Chen, Northeastern Univ. (China)
Yang Tao, Univ. of Maryland (United States)

Published in SPIE Proceedings Vol. 6913:
Medical Imaging 2008: Physics of Medical Imaging
Jiang Hsieh; Ehsan Samei, Editor(s)

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