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Proceedings Paper

Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector
Author(s): Olivier Tousignant; Yves Demers; Luc Laperriere; Habib Mani; Philippe Gauthier; Jonathan Leboeuf
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Paper Abstract

Large area, real-time, amorphous selenium (a-Se) based Flat Panel Detectors (FPD) were recently equipped with low noise front end electronics. In full resolution, 14”x14” detectors (FPD14) and 9”x9” detectors (FPD9) show an electronic noise of 1400 electrons. To evaluate the positive impact of such low noise on image quality, a dedicated report on spatial characteristics (MTF, NPS and DQE) covering the low dose range from 0.6 μR to 12 μR per frame, will be presented in the first section of this paper. For one RQA5 beam quality, DQE corrected for lag extrapolated at zero spatial frequency was equal to 0.6 for quantum noise limited exposure and equal to 0.4 for 0.6 μR. Almost no difference was found between 1x1 and 2x2 resolution mode giving the opportunity to 1x1 fluoroscopy. Recent advances to reduce image temporal artifacts such as lag and ghost will make the second part of this paper. It is demonstrated that the most significant contribution to detector lag is coming from the PIN selenium structure. Above electric field of 10 V/μm charges release from traps following one x-ray exposure could not explain selenium lag. Active ghost correction based on deep trapped charge recombination was developed giving good preliminary results in showing no residual ghost for a high dose rate of 33 mR/min.

Paper Details

Date Published: 20 April 2005
PDF: 9 pages
Proc. SPIE 5745, Medical Imaging 2005: Physics of Medical Imaging, (20 April 2005); doi: 10.1117/12.602183
Show Author Affiliations
Olivier Tousignant, Anrad Corp. (Canada)
Yves Demers, Anrad Corp. (Canada)
Luc Laperriere, Anrad Corp. (Canada)
Habib Mani, Anrad Corp. (Canada)
Philippe Gauthier, Anrad Corp. (Canada)
Jonathan Leboeuf, Anrad Corp. (Canada)


Published in SPIE Proceedings Vol. 5745:
Medical Imaging 2005: Physics of Medical Imaging
Michael J. Flynn, Editor(s)

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