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6 May 2004 Design and performance of a new a-Si flat-panel imager for use in cardiovascular and mobile C-arm imaging systems
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This paper describes a new flat panel imager designed for use in cardiovascular and mobile C-arm imaging systems. The a-Si sensor array has a 1024 x 1024 matrix with a pixel pitch of 194 μm, resulting in an active area of 198.7 mm x 198.7 mm. The imager allows frame rates of up to 30 fps in full resolution fluoroscopy mode and up to 60 fps in a 2 x 2 binned low dose fluoroscopy mode. Typically, a 600 μm thick deposited columnar CsI(Tl) layer is used as the scintillator. Improvements in the pixel architecture, charge amplifier ASICs, and system level electronics resulted in a very low electronic noise floor, such that both the fluoroscopy and low dose fluoroscopy modes of the panel are x-ray quantum limited below 1 μR/frame. Low power consumption electronics combined with a mechanical design optimized for heat transfer and dissipation makes air-cooling sufficient for most environments. The small size of 24.1 x 24.1 x 6 cm and the weight of only 4.1 kg meet the requirements of C-Arm systems. Special consideration was given to the border around the active area, which has been reduced to 2 cm. Reported performance parameters include linearity, lag, contrast ratio, MTF, and DQE. For the full resolution mode, the MTF is greater than 0.53 and 0.21 at 1 and 2 lp/mm, respectively. DQE measured at 22 nGy/frame was greater than 0.68, 0.50, and 0.23 at 0, 1, and 2 lp/mm, respectively.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Carlo A. Tognina, Ivan Mollov, Jiann M. Yu, Chris Webb, Pieter G. Roos, Mark Batts, Delenah Trinh, Robert Fong, Nima Taie-Nobraie, Boris Nepo, Isaias D. Job, Keith Gray, Sarah Boyce, and Richard E. Colbeth "Design and performance of a new a-Si flat-panel imager for use in cardiovascular and mobile C-arm imaging systems", Proc. SPIE 5368, Medical Imaging 2004: Physics of Medical Imaging, (6 May 2004);

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