Paper
24 July 1998 Improved spatial resolution in flat-panel imaging systems
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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.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John Yorkston, Larry E. Antonuk, Youcef El-Mohri, Kyung-Wook Jee, Weidong Huang, Manat Maolinbay, Xiujiang Rong, Jeffrey H. Siewerdsen, and David P. Trauernicht "Improved spatial resolution in flat-panel imaging systems", Proc. SPIE 3336, Medical Imaging 1998: Physics of Medical Imaging, (24 July 1998); https://doi.org/10.1117/12.317058
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Cited by 9 scholarly publications.
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KEYWORDS
Glasses

X-rays

Modulation transfer functions

Imaging systems

Spatial resolution

Backscatter

Monte Carlo methods

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