CdZnTe is one of the most promising semiconductor material in the field of digital X-ray imaging,... more CdZnTe is one of the most promising semiconductor material in the field of digital X-ray imaging, and may be operated at room temperature. To improve the detector characteristics, ternary systems such as Cd1-xZnxTe were grown by the high pressure Bridgman (HPG) technique. The signal performance characteristics of quasi-resistive Cd1-xZnxTe semiconductor detectors, was studied at different directions of irradiation, within the X-ray diagnostic energy range. The experimental results suggest that the total efficiency of these semiconductor detectors depends upon the energy absorption efficiency as well as the charge collection efficiency. This imaging detector allows one to investigate methods to improve the detection and imaging performance parameters as part of the development of an X-ray imaging system.
Proceedings of the 17th IEEE Instrumentation and Measurement Technology Conference [Cat. No. 00CH37066], 2000
The contrast sensitivity and dynamic range of Cd1-xZn xTe semiconductor detectors have been measu... more The contrast sensitivity and dynamic range of Cd1-xZn xTe semiconductor detectors have been measured within the X-ray diagnostic energy range, using a contrast sensitivity phantom. The aim of this study is to optimize the image quality parameters of these solid state-ionization devices for flat panel digital radiographic applications. The experimental results of this study indicate that Cd 1-xZnxTe detectors have
The Kinestatic Charge Detector (KCD) technique of projection radiography shows promise when used ... more The Kinestatic Charge Detector (KCD) technique of projection radiography shows promise when used for dual- energy imaging, which may be performed either by taking two separate exposures at different kVp settings (the dual-kVp method) or by taking a single exposure with the KCD segmented into a front and back region (the split-detector method), as the higher energy photons will be preferentially absorbed in the back region. Using computer simulations, we have optimized the dual-energy performance of a segmented KCD using the split-detector method for chest radiography. Theoretical optimization of imaging parameters and determination of contrast resolution were performed by minimizing pixel variances of the basis materials. The expected contrast resolution of the aluminum and plexiglas basis material images was found to be acceptable for purposes of clinical diagnosis. A detector medium of krypton produced better results than xenon at the same density, and the optimal kVp setting was ...
In this paper, the detected signal-to-noise was measured and related to the tube current (mA) set... more In this paper, the detected signal-to-noise was measured and related to the tube current (mA) setting. The line spread function amplitude (LSF) dependence on drift distance of a 3 mm thick detector, for 100 kVp, 100 mA, with an applied electric field of 50 V/mm, and 100 V/mm, were measured. In addition, the dependence of the modulation transfer function [MTF(f)]
The detected contrast and dynamic ranges of Cd 1-x Zn x Te semiconductor detectors have been meas... more The detected contrast and dynamic ranges of Cd 1-x Zn x Te semiconductor detectors have been measured, within the X-ray diagnostic energy range, using a contrast sensitivity phantom. The aim of this study is to optimize the image quality parameters of ...
IEEE Transactions on Instrumentation and Measurement, 2004
In this paper, the detective quantum efficiency (DQE) of cadmium zinc telluride (CZT) detector sa... more In this paper, the detective quantum efficiency (DQE) of cadmium zinc telluride (CZT) detector samples for digital radiography has been measured. Specifically, this study is aimed at investigating the zero-frequency DQE(0) under different X-ray tube and detector parameters. The experimental results of this study indicate that the DQE(0) of the CZT samples is strongly dependent upon the irradiation geometry. This
Journal of X-Ray Science and Technology 12 (2004) 111 ... Vincent J. Schmithorst a , Robert J. E... more Journal of X-Ray Science and Technology 12 (2004) 111 ... Vincent J. Schmithorst a , Robert J. Endorf a , Sunil Kulatunga a , David C. Spelic a , ... Frank A. DiBianca b , Carlos Rodriguez b , Herbert D. Zeman b , Zeping Zhu b and ... George C. Giakos c a Physics Department, ...
The Tutorials in Introductory Physics, by Lillian McDermott, Peter Shaffer and the Physics Educat... more The Tutorials in Introductory Physics, by Lillian McDermott, Peter Shaffer and the Physics Education Group at the University of Washington, have been adapted and implemented in the recitation sections of the large introductory calculus-based physics courses taught at the University of Cincinnati. These courses are now taken by approximately 700 students each year, most of whom are first year engineering
A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluat... more A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluate the imaging performance of the single-scan dual energy x-ray KCD system. Those front segments of the KCD collectors will produce a low energy signal and those rear segments will produce a high energy signal. The middle segments between the front and rear work as an inactive
A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluat... more A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluate the imaging performance of the single-scan dual energy x-ray KCD system. Those front segments of the KCD collectors will produce a low energy signal and those rear segments will produce a high energy signal. The middle segments between the front and rear work as an inactive
Medical Imaging 1996: Physics of Medical Imaging, 1996
ABSTRACT A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built t... more ABSTRACT A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluate the imaging performance of the single-scan dual energy x-ray KCD system. Those front segments of the KCD collectors will produce a low energy signal and those rear segments will produce a high energy signal. The middle segments between the front and rear work as an inactive filter to increase the separation of mean energies absorbed in the front and rear segments. In this study, the segmented KCD output signals were measured and compared with the Monte Carlo simulated result. An optimal KCD collector configuration is gotten by mapping the low energy and high energy signal amplitude to the predetermined thickness of the lucite-aluminum wedge-phantom (0-228.6 mm lucite and 0-25.4 mm aluminum), and then performing error analysis between the calculated thickness and known thickness.
CdZnTe is one of the most promising semiconductor material in the field of digital X-ray imaging,... more CdZnTe is one of the most promising semiconductor material in the field of digital X-ray imaging, and may be operated at room temperature. To improve the detector characteristics, ternary systems such as Cd1-xZnxTe were grown by the high pressure Bridgman (HPG) technique. The signal performance characteristics of quasi-resistive Cd1-xZnxTe semiconductor detectors, was studied at different directions of irradiation, within the X-ray diagnostic energy range. The experimental results suggest that the total efficiency of these semiconductor detectors depends upon the energy absorption efficiency as well as the charge collection efficiency. This imaging detector allows one to investigate methods to improve the detection and imaging performance parameters as part of the development of an X-ray imaging system.
Proceedings of the 17th IEEE Instrumentation and Measurement Technology Conference [Cat. No. 00CH37066], 2000
The contrast sensitivity and dynamic range of Cd1-xZn xTe semiconductor detectors have been measu... more The contrast sensitivity and dynamic range of Cd1-xZn xTe semiconductor detectors have been measured within the X-ray diagnostic energy range, using a contrast sensitivity phantom. The aim of this study is to optimize the image quality parameters of these solid state-ionization devices for flat panel digital radiographic applications. The experimental results of this study indicate that Cd 1-xZnxTe detectors have
The Kinestatic Charge Detector (KCD) technique of projection radiography shows promise when used ... more The Kinestatic Charge Detector (KCD) technique of projection radiography shows promise when used for dual- energy imaging, which may be performed either by taking two separate exposures at different kVp settings (the dual-kVp method) or by taking a single exposure with the KCD segmented into a front and back region (the split-detector method), as the higher energy photons will be preferentially absorbed in the back region. Using computer simulations, we have optimized the dual-energy performance of a segmented KCD using the split-detector method for chest radiography. Theoretical optimization of imaging parameters and determination of contrast resolution were performed by minimizing pixel variances of the basis materials. The expected contrast resolution of the aluminum and plexiglas basis material images was found to be acceptable for purposes of clinical diagnosis. A detector medium of krypton produced better results than xenon at the same density, and the optimal kVp setting was ...
In this paper, the detected signal-to-noise was measured and related to the tube current (mA) set... more In this paper, the detected signal-to-noise was measured and related to the tube current (mA) setting. The line spread function amplitude (LSF) dependence on drift distance of a 3 mm thick detector, for 100 kVp, 100 mA, with an applied electric field of 50 V/mm, and 100 V/mm, were measured. In addition, the dependence of the modulation transfer function [MTF(f)]
The detected contrast and dynamic ranges of Cd 1-x Zn x Te semiconductor detectors have been meas... more The detected contrast and dynamic ranges of Cd 1-x Zn x Te semiconductor detectors have been measured, within the X-ray diagnostic energy range, using a contrast sensitivity phantom. The aim of this study is to optimize the image quality parameters of ...
IEEE Transactions on Instrumentation and Measurement, 2004
In this paper, the detective quantum efficiency (DQE) of cadmium zinc telluride (CZT) detector sa... more In this paper, the detective quantum efficiency (DQE) of cadmium zinc telluride (CZT) detector samples for digital radiography has been measured. Specifically, this study is aimed at investigating the zero-frequency DQE(0) under different X-ray tube and detector parameters. The experimental results of this study indicate that the DQE(0) of the CZT samples is strongly dependent upon the irradiation geometry. This
Journal of X-Ray Science and Technology 12 (2004) 111 ... Vincent J. Schmithorst a , Robert J. E... more Journal of X-Ray Science and Technology 12 (2004) 111 ... Vincent J. Schmithorst a , Robert J. Endorf a , Sunil Kulatunga a , David C. Spelic a , ... Frank A. DiBianca b , Carlos Rodriguez b , Herbert D. Zeman b , Zeping Zhu b and ... George C. Giakos c a Physics Department, ...
The Tutorials in Introductory Physics, by Lillian McDermott, Peter Shaffer and the Physics Educat... more The Tutorials in Introductory Physics, by Lillian McDermott, Peter Shaffer and the Physics Education Group at the University of Washington, have been adapted and implemented in the recitation sections of the large introductory calculus-based physics courses taught at the University of Cincinnati. These courses are now taken by approximately 700 students each year, most of whom are first year engineering
A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluat... more A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluate the imaging performance of the single-scan dual energy x-ray KCD system. Those front segments of the KCD collectors will produce a low energy signal and those rear segments will produce a high energy signal. The middle segments between the front and rear work as an inactive
A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluat... more A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluate the imaging performance of the single-scan dual energy x-ray KCD system. Those front segments of the KCD collectors will produce a low energy signal and those rear segments will produce a high energy signal. The middle segments between the front and rear work as an inactive
Medical Imaging 1996: Physics of Medical Imaging, 1996
ABSTRACT A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built t... more ABSTRACT A kinestatic charge detector (KCD) with fourteen segmented signal collectors was built to evaluate the imaging performance of the single-scan dual energy x-ray KCD system. Those front segments of the KCD collectors will produce a low energy signal and those rear segments will produce a high energy signal. The middle segments between the front and rear work as an inactive filter to increase the separation of mean energies absorbed in the front and rear segments. In this study, the segmented KCD output signals were measured and compared with the Monte Carlo simulated result. An optimal KCD collector configuration is gotten by mapping the low energy and high energy signal amplitude to the predetermined thickness of the lucite-aluminum wedge-phantom (0-228.6 mm lucite and 0-25.4 mm aluminum), and then performing error analysis between the calculated thickness and known thickness.
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Papers by Robert J. Endorf