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Proceedings Paper

Improved spatial resolution in flat-panel imaging systems
Author(s): John Yorkston; Larry E. Antonuk; Youcef El-Mohri; Kyung-Wook Jee; Weidong Huang; Manat Maolinbay; Xiujiang Rong; Jeffrey H. Siewerdsen; David P. Trauernicht
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Paper Abstract

Results of an investigation into the limiting spatial resolution of a flat-panel amorphous silicon (a-Si:H) X-ray imaging system are reported. The system was comprised of a 127 micrometer pixel pitch a-Si:H array used in conjunction with an overlying Gd2O2S:Tb (GOS) phosphor screen. The pre- sampled modulation transfer function (psMTF) of the system was measured at diagnostic X-ray energies and compared to the value predicted from a knowledge of the spatial resolution of the individual system components. A reproducible drop in the measured psMTF is seen at low spatial frequencies. Measurements of the magnitude of X-ray backscatter from the array substrate, along with the results of a theoretical model for K-fluorescence X-ray scatter, indicate that a significant fraction of this low-frequency drop is due to K-fluorescence from heavy elements in the glass substrate of the array. This K-fluorescence may be excited directly by primary X-rays that penetrate the overlying phosphor and interact in the glass, or by gadolinium K-fluorescence X-rays that escape from the phosphor into the glass. The measurements indicate that the spatial resolution of such an X-ray imaging system may be improved by the use of a substrate containing as low a concentration of heavy elements as possible.

Paper Details

Date Published: 24 July 1998
PDF: 8 pages
Proc. SPIE 3336, Medical Imaging 1998: Physics of Medical Imaging, (24 July 1998); doi: 10.1117/12.317058
Show Author Affiliations
John Yorkston, Univ. of Michigan (United States)
Larry E. Antonuk, Univ. of Michigan (United States)
Youcef El-Mohri, Univ. of Michigan (United States)
Kyung-Wook Jee, Univ. of Michigan (United States)
Weidong Huang, Univ. of Michigan (United States)
Manat Maolinbay, Univ. of Michigan (United States)
Xiujiang Rong, Univ. of Michigan (United States)
Jeffrey H. Siewerdsen, Univ. of Michigan (Canada)
David P. Trauernicht, Eastman Kodak Co. (United States)

Published in SPIE Proceedings Vol. 3336:
Medical Imaging 1998: Physics of Medical Imaging
James T. Dobbins III; John M. Boone, Editor(s)

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