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Proceedings Paper

Low-noise pixel architecture for advanced diagnostic medical x-ray imaging applications
Author(s): M. H. Izadi; K. S. Karim; A. Nathan; J. A. Rowlands
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Paper Abstract

The most widely used architecture in large-area amorphous silicon (a-Si) flat panel imagers is a passive pixel sensor (PPS), which consists of a detector element and a readout switch. While the PPS has the advantage of being compact and amenable toward high-resolution imaging, reading small PPS output signals requires external column charge amplifiers that produce additional noise and reduce the minimum readable sensor input signal. In contrast, on-pixel amplifiers in a-Si technology reduce readout noise by decoupling off-pixel noise sources, such as external charge amplifier and data line noise, from the sensor input. The off-pixel noise is reduced by the charge gain of the pixel amplifier, allowing for low-noise performance. Theoretical calculations and simulations of gain, linearity, metastability, pixel area requirements and noise indicate the applicability of the amplified a-Si pixel architectures for low-exposure, real-time fluoroscopy. In addition, the detailed noise results allow for the computation of noise performance as a function of transistor dimensions for both amorphous silicon and polysilicon technologies, allowing the designer to choose appropriate device dimensions when designing flat-panel imaging circuits.

Paper Details

Date Published: 2 March 2006
PDF: 11 pages
Proc. SPIE 6142, Medical Imaging 2006: Physics of Medical Imaging, 61420T (2 March 2006); doi: 10.1117/12.654900
Show Author Affiliations
M. H. Izadi, Simon Fraser Univ. (Canada)
K. S. Karim, Simon Fraser Univ. (Canada)
A. Nathan, Univ. of Waterloo (Canada)
J. A. Rowlands, Sunnybrook and Women's College Health Sciences Ctr., Univ. of Toronto (Canada)

Published in SPIE Proceedings Vol. 6142:
Medical Imaging 2006: Physics of Medical Imaging
Michael J. Flynn; Jiang Hsieh, Editor(s)

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