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Proceedings Paper

Experimental measurement of the modulation transfer function of differential phase contrast CT systems
Author(s): Ke Li; Nicholas Bevins; Joseph Zambelli; Guang-Hong Chen
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Paper Abstract

This paper concerns an experimental method to quantify the spatial resolution of an experimental DPC-CT system via modulation transfer function (MTF) measurement. Note that conventional metal wire-based MTF measurement methods are no long applicable to DPC-CT, because: (i) The refractive signal generated by the high density metal is out of the dynamic range of DPC-CT, and (ii) A DPC-CT system is not sensitive to input pulse finer than a detector pixel. These technical challenges were overcome by a new experimental design, in which a graphite rod was used as the probe to simultaneously measure the MTFs of the DPC-CT and the associated absorption CT. An appreciable difference in MTFs between DPC-CT and absorption CT was observed in our experimental benchtop system: At the 10% MTF level, the MTFs of the DPC-CT and the absorption CT are 4.7 cycles/mm and 5.2 cycles/mm, respectively. Such a difference in MTF leads to the conclusion that the grating interferometer used by the DPC-CT system has a frequency-dependent response to input DPC-CT signals.

Paper Details

Date Published: 19 March 2013
PDF: 7 pages
Proc. SPIE 8668, Medical Imaging 2013: Physics of Medical Imaging, 866856 (19 March 2013); doi: 10.1117/12.2008081
Show Author Affiliations
Ke Li, Univ. of Wisconsin-Madison (United States)
Nicholas Bevins, Univ. of Wisconsin-Madison (United States)
Joseph Zambelli, Univ. of Wisconsin-Madison (United States)
Guang-Hong Chen, Univ. of Wisconsin-Madison (United States)

Published in SPIE Proceedings Vol. 8668:
Medical Imaging 2013: Physics of Medical Imaging
Robert M. Nishikawa; Bruce R. Whiting; Christoph Hoeschen, Editor(s)

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