19 March 2014 High-performance soft-tissue imaging in extremity cone-beam CT
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Abstract
Purpose: Clinical performance studies of an extremity cone-beam CT (CBCT) system indicate excellent bone visualization, but point to the need for improvement of soft-tissue image quality. To this end, a rapid Monte Carlo (MC) scatter correction is proposed, and Penalized Likelihood (PL) reconstruction is evaluated for noise management. Methods: The accelerated MC scatter correction involved fast MC simulation with low number of photons implemented on a GPU (107 photons/sec), followed by Gaussian kernel smoothing in the detector plane and across projection angles. PL reconstructions were investigated for reduction of imaging dose for projections acquired at ~2 mGy. Results: The rapid scatter estimation yielded root-mean-squared-errors of scatter projections of ~15% of peak scatter intensity for 5⋅106 photons/projection (runtime ~0.5 sec/projection) and 25% improvement in fat-muscle contrast in reconstructions of a cadaveric knee. PL reconstruction largely restored soft-tissue visualization at 2 mGy dose to that of 10 mGy FBP image. Conclusion: The combination of rapid (5-10 minutes/scan) MC-based, patient-specific scatter correction and PL reconstruction offers an important means to overcome the current limitations of extremity CBCT in soft-tissue imaging.
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W. Zbijewski, W. Zbijewski, A. Sisniega, A. Sisniega, J. W. Stayman, J. W. Stayman, A. Muhit, A. Muhit, G. Thawait, G. Thawait, N. Packard, N. Packard, R. Senn, R. Senn, D. Yang, D. Yang, J. Yorkston, J. Yorkston, J. A. Carrino, J. A. Carrino, J. H. Siewerdsen, J. H. Siewerdsen, } "High-performance soft-tissue imaging in extremity cone-beam CT", Proc. SPIE 9033, Medical Imaging 2014: Physics of Medical Imaging, 903329 (19 March 2014); doi: 10.1117/12.2043463; https://doi.org/10.1117/12.2043463
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