Dr. Samuel Richard Profile

Dr. Samuel Richard

Research Scientist at Carestream Health Inc

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Publications (13)

Proceedings Article | 19 March 2014 Paper

Size-specific dose estimates (SSDE) for a prototype orthopedic cone-beam CT system

Samuel Richard, Nathan Packard, John Yorkston

Proceedings Volume 9033, 90331S (2014) https://doi.org/10.1117/12.2043032

KEYWORDS: Imaging systems, Scanners, Prototyping, Factor analysis, Sensors, X-ray computed tomography, Ions, Medical imaging, X-ray imaging, Copper

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Proceedings Article | 6 March 2013 Paper

Physical model-based metal artifact reduction (MAR) scheme for a 3D cone-beam CT extremity imaging system

D. Yang, R. Senn, N. Packard, S. Richard, J. Yorkston

Proceedings Volume 8668, 86685T (2013) https://doi.org/10.1117/12.2006207

KEYWORDS: Metals, Imaging systems, X-ray computed tomography, Reconstruction algorithms, Sensors, Image segmentation, X-rays, 3D modeling, CT reconstruction, Signal processing

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Proceedings Article | 9 March 2012 Paper

Relevance of MTF and NPS in quantitative CT: towards developing a predictable model of quantitative performance

Baiyu Chen, Samuel Richard, Ehsan Samei

Proceedings Volume 8313, 83132O (2012) https://doi.org/10.1117/12.913219

KEYWORDS: Reconstruction algorithms, Computed tomography, Precision measurement, Lung, Modulation transfer functions, Chest, Image segmentation, Mathematical modeling, Performance modeling, Scanners

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Proceedings Article | 24 February 2012 Paper

CT performance as a variable function of resolution, noise, and task property for iterative reconstructions

Baiyu Chen, Samuel Richard, Olav Christianson, Xiaodong Zhou, Ehsan Samei

Proceedings Volume 8313, 83131K (2012) https://doi.org/10.1117/12.913220

KEYWORDS: Reconstruction algorithms, Infrared imaging, IRIS Consortium, Eye models, Scanners, Optical filters, Image resolution, Physics, Medicine, Image quality

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Proceedings Article | 17 March 2011 Paper

Predictive models for observer performance in CT: applications in protocol optimization

S. Richard, X. Li, G. Yadava, E. Samei

Proceedings Volume 7961, 79610H (2011) https://doi.org/10.1117/12.877069

KEYWORDS: Modulation transfer functions, Performance modeling, Eye models, Reconstruction algorithms, Computed tomography, Optimization (mathematics), Eye, X-ray computed tomography, Imaging systems, Image filtering

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Proceedings Article | 17 March 2011 Paper

3D task-based performance assessment metrics for optimization of performance and dose in breast tomosynthesis

S. Richard, E. Samei

Proceedings Volume 7961, 79611A (2011) https://doi.org/10.1117/12.877070

KEYWORDS: Modulation transfer functions, Breast, Optical spheres, Imaging systems, 3D modeling, Systems modeling, 3D metrology, 3D image processing, Stereoscopy, 3D acquisition

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Proceedings Article | 23 March 2010 Paper

Extending the detectability index to quantitative imaging performance: applications in tomosynthesis and CT

Samuel Richard, Baiyu Chen, Ehsan Samei

Proceedings Volume 7622, 76220Z (2010) https://doi.org/10.1117/12.845286

KEYWORDS: Modulation transfer functions, Imaging systems, Breast, Performance modeling, 3D modeling, Systems modeling, Statistical analysis, 3D acquisition, Medical imaging, Optical spheres

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Proceedings Article | 23 March 2010 Paper

Quantitative CT: technique dependency of volume assessment for pulmonary nodules

Baiyu Chen, Samuel Richard, Huiman Barnhart, James Colsher, Maxwell Amurao, Ehsan Samei

Proceedings Volume 7622, 76222W (2010) https://doi.org/10.1117/12.845493

KEYWORDS: 3D imaging standards, Computed tomography, Lung, Statistical analysis, Image segmentation, 3D image reconstruction, Solids, 3D acquisition, Physics, Scanners

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Proceedings Article | 19 March 2010 Paper

Wide-angle breast tomosynthesis: initial comparative evaluation

John Thompson, Baiyu Chen, Samuel Richard, James Bowsher, Ehsan Samei

Proceedings Volume 7622, 76220C (2010) https://doi.org/10.1117/12.845649

KEYWORDS: Breast, Monte Carlo methods, Digital breast tomosynthesis, Tissues, Computed tomography, Expectation maximization algorithms, Calibration, Mammography, Sensors, Chest

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Proceedings Article | 18 March 2008 Paper

NEQ and task in dual-energy imaging: from cascaded systems analysis to human observer performance

Samuel Richard, Jeffrey Siewerdsen, Daniel Tward

Proceedings Volume 6913, 691311 (2008) https://doi.org/10.1117/12.772772

KEYWORDS: Imaging systems, Modulation transfer functions, Image filtering, Optical spheres, Eye models, Eye, Linear filtering, Electronic filtering, Laser sintering, Systems modeling

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Proceedings Article | 20 March 2007 Paper

Development and implementation of a high-performance cardiac-gated dual-energy imaging system

N. Shkumat, J. Siewerdsen, A. Dhanantwari, D. Williams, S. Richard, D. Tward, N. Paul, J. Yorkston, R. Van Metter

Proceedings Volume 6510, 651006 (2007) https://doi.org/10.1117/12.713680

KEYWORDS: Imaging systems, X-rays, Radiography, Lung, Heart, Diagnostics, Oximeters, Image filtering, Image processing, Sensors

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Proceedings Article | 2 March 2006 Paper

High-performance dual-energy imaging with a flat-panel detector: imaging physics from blackboard to benchtop to bedside

J. Siewerdsen, N. Shkumat, A. Dhanantwari, D. Williams, S. Richard, M. Daly, N. Paul, D. Moseley, D. Jaffray, J. Yorkston, R. Van Metter

Proceedings Volume 6142, 61421E (2006) https://doi.org/10.1117/12.658080

KEYWORDS: Imaging systems, Sensors, Image acquisition, Oximeters, Dual energy imaging, Lung, Radiography, Diagnostics, Silver, X-rays

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The application of high-performance flat-panel detectors (FPDs) to dual-energy (DE) imaging offers the potential for dramatically improved detection and characterization of subtle lesions through reduction of "anatomical noise," with applications ranging from thoracic imaging to image-guided interventions. In this work, we investigate DE imaging performance from first principles of image science to preclinical implementation, including: 1.) generalized task-based formulation of NEQ and detectability as a guide to system optimization; 2.) measurements of imaging performance on a DE imaging benchtop; and 3.) a preclinical system developed in our laboratory for cardiac-gated DE chest imaging in a research cohort of 160 patients. Theoretical and benchtop studies directly guide clinical implementation, including the advantages of double-shot versus single-shot DE imaging, the value of differential added filtration between low- and high-kVp projections, and optimal selection of kVp pairs, filtration, and dose allocation. Evaluation of task-based NEQ indicates that the detectability of subtle lung nodules in double-shot DE imaging can exceed that of single-shot DE imaging by a factor of 4 or greater. Filter materials are investigated that not only harden the high-kVp beam (e.g., Cu or Ag) but also soften the low-kVp beam (e.g., Ce or Gd), leading to significantly increased contrast in DE images. A preclinical imaging system suitable for human studies has been constructed based upon insights gained from these theoretical and experimental studies. An important component of the system is a simple and robust means of cardiac-gated DE image acquisition, implemented here using a fingertip pulse oximeter. Timing schemes that provide cardiac-gated image acquisition on the same or successive heartbeats is described. Preclinical DE images to be acquired under research protocol will afford valuable testing of optimal deployment, facilitate the development of DE CAD, and support comparison of DE diagnostic imaging performance to low-dose CT and radiography.

Proceedings Article | 20 April 2005 Paper

Generalized DQE analysis of dual-energy imaging using flat-panel detectors

S. Richard, J. Siewerdsen, D. Jaffray, D. Moseley, B. Bakhtiar

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.595534

KEYWORDS: Imaging systems, Tissues, Sensors, Quantum efficiency, Spatial frequencies, Dual energy imaging, Chest, Modulation transfer functions, Image processing, Quantum electronics

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Showing 5 of 13 publications

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