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Proceedings Paper

Investigation of Moiré pattern-based phase retrieval approach for differential phase-contrast cone beam CT imaging using a hospital-grade tube
Author(s): Weixing Cai; Ruola Ning; Yang Yu; Jiangkun Liu; David Conover
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Paper Abstract

The phase stepping algorithm is commonly used for phase retrieval in grating-based differential phase-contrast (DPC) imaging, which requires multiple intensity images to compute one DPC image. It is not efficient for data acquisition, especially in the case of dynamic imaging using either DPC imaging or DPC-based come beam CT (DPC-CBCT) imaging. A Fourier transform-based approach has been developed for fringe pattern analysis in optics, and it was recently implemented into a synchrotron-based DPC tomography system. In this research, this approach is further developed for a bench-top DPC-CBCT imaging system with a hospital-grade x-ray tube. The key idea is to separate carrier fringes and object information in Fourier domain of the interferogram and to reconstruct the differentiated phase information using the object information. Only one interferogram is required for phase retrieval at a cost of spatial resolution. The fringes of moiré patterns are used as the carrier fringes, and a phantom is scanned to evaluate the approach. Various interferograms with different carrier fringe frequencies are investigated and the reconstruction image quality is evaluated in terms of contrast, noise and sharpness. The results indicated that the DPC images can be effectively retrieved using the Fourier transform-based approach and the reconstructed phase coefficient showed better contrast compared to that of attenuation-based contrast. The spatial resolution is acceptable in the phantom studies although it is not as good as the results of phase-stepping approach. The Fourier transform-based phase retrieval approach is able to greatly simplify data acquisition, to improve the temporal resolution and to make it possible for dynamic DPC-CBCT imaging. It is promising for perfusion imaging where spatial resolution is not a concern.

Paper Details

Date Published: 9 March 2012
PDF: 8 pages
Proc. SPIE 8313, Medical Imaging 2012: Physics of Medical Imaging, 83132R (9 March 2012); doi: 10.1117/12.911342
Show Author Affiliations
Weixing Cai, Univ. of Rochester Medical Ctr. (United States)
Ruola Ning, Univ. of Rochester Medical Ctr. (United States)
Univ. of Rochester (United States)
Yang Yu, Univ. of Rochester (United States)
Jiangkun Liu, Univ. of Rochester (United States)
David Conover, Koning Corp. (United States)

Published in SPIE Proceedings Vol. 8313:
Medical Imaging 2012: Physics of Medical Imaging
Norbert J. Pelc; Robert M. Nishikawa; Bruce R. Whiting, Editor(s)

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