Paper
2 March 2006 Substrate effect on indirect digital radiography system performance
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Abstract
In a typical indirect flat-panel digital radiography detector, a phosphor screen is coupled to an a-Si:H imaging array, whose pixels comprise an a-Si:H photodiode and an a-Si:H TFT switch. This two-dimensional array is fabricated on a thin glass substrate that usually contains a rather high concentration of heavy elements such as barium. In previous system performance analyses, only the effect of K-fluorescence reabsorption in the phosphor screen was included. The effect of K-fluorescence from heavy elements in the glass substrate of the array was not taken into account. This K-fluorescence may be excited directly by primary x-rays that penetrate the overlying phosphor and interact in the glass, or by K-fluorescence x-rays that escape from the phosphor into the glass. In this paper, we extend the parallel-cascaded linear systems model to include the effect of K-fluorescence from heavy elements in the glass substrate. As an example, the MTF, NPS, and DQE of an indirect flat-panel imager consisting of a Gd2O2S:Tb phosphor screen and an a-Si:H photodiode/TFT array fabricated on a glass substrate containing barium, are calculated. Degradations in MTF and DQE as a result of the K-fluorescence from the substrate are presented and discussed.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
A. R. Lubinsky, Kwok L. Yip, David P. Trauernicht, and John Yorkston "Substrate effect on indirect digital radiography system performance", Proc. SPIE 6142, Medical Imaging 2006: Physics of Medical Imaging, 61423J (2 March 2006); https://doi.org/10.1117/12.655564
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Cited by 2 scholarly publications.
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KEYWORDS
Gadolinium

X-rays

Barium

Modulation transfer functions

Glasses

Photons

Imaging systems

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