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Proceedings Paper

Analysis of axial spatial resolution in a variable resolution x-ray cone beam CT (VRX-CBCT) system
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Paper Abstract

The Variable Resolution X-ray (VRX) technique has been successfully used in a Cone-Beam CT (CBCT) system to increase the spatial resolution of CT images in the transverse plane. This was achieved by tilting the Flat Panel Detector (FPD) to smaller vrxy angles in a VRX Cone Beam CT (VRX-CBCT) system. In this paper, the effect on the axial spatial resolution of CT images created by the VRX-CBCT system is examined at different vrxx angles, where vrxx is the tilting angle of the FPD about its x-axis. An amorphous silicon FPD with a CsI scintillator is coupled with a micro-focus x-ray tube to form a CBCT. The FPD is installed on a rotating frame that allows rotation of up to 90° about x and y axes of the FPD. There is no rotation about the z-axis (i.e. normal to the imaging surface). Tilting the FPD about its x-axis (i.e. decreasing the vrxx angle) reduces both the width of the line-spread function and the sampling distance by a factor of sin vrxx, thereby increasing the theoretical detector pre-sampling spatial resolution proportionately. This results in thinner CT slices that in turn help increase the axial spatial resolution of the CT images. An in-house phantom is used to measure the MTF of the reconstructed CT images at different vrxx angles.

Paper Details

Date Published: 19 March 2008
PDF: 8 pages
Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 69134Y (19 March 2008); doi: 10.1117/12.773068
Show Author Affiliations
Bahram Dahi, The Univ. of Tennessee Health Science Ctr. (United States)
Gary S. Keyes, The Univ. of Tennessee Health Science Ctr. (United States)
David A. Rendon, The Univ. of Tennessee Health Science Ctr. (United States)
Frank A. DiBianca, The Univ. of Tennessee Health Science Ctr. (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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