13 March 2009 Dual energy CT via fast kVp switching spectrum estimation
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Proceedings Volume 7258, Medical Imaging 2009: Physics of Medical Imaging; 72583T (2009) https://doi.org/10.1117/12.811650
Event: SPIE Medical Imaging, 2009, Lake Buena Vista (Orlando Area), Florida, United States
Abstract
Recently there has been significant interest in dual energy CT imaging with several acquisition methods being actively pursued. Here we investigate fast kVp switching where the kVp alternates between low and high kVp every view. Fast kVp switching enables fine temporal registration, helical and axial acquisitions, and full field of view. It also presents several processing challenges. The rise and fall of the kVp, which occurs during the view integration period, is not instantaneous and complicates the measurement of the effective spectrum for low and high kVp views. Further, if the detector digital acquisition system (DAS) and generator clocks are not fully synchronous, jitter is introduced in the kVp waveform relative to the view period. In this paper we develop a method for estimation of the resulting spectrum for low and high kVp views. The method utilizes static kVp acquisitions of air with a small bowtie filter as a basis set. A fast kVp acquisition of air with a small bowtie filter is performed and the effective kVp is estimated as a linear combination of the basis vectors. The effectiveness of this method is demonstrated through the reconstruction of a water phantom acquired with a fast kVp acquisition. The impact of jitter due to the generator and detector DAS clocks is explored via simulation. The error is measured relative to spectrum variation and material decomposition accuracy.
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Dan Xu, David A. Langan, Xiaoye Wu, Jed D. Pack, Thomas M. Benson, J. Eric Tkaczky, Andrea M. Schmitz, "Dual energy CT via fast kVp switching spectrum estimation", Proc. SPIE 7258, Medical Imaging 2009: Physics of Medical Imaging, 72583T (13 March 2009); doi: 10.1117/12.811650; https://doi.org/10.1117/12.811650
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