George Zentai - Academia.edu (original) (raw)

Papers by George Zentai

Research paper thumbnail of TH-EF-BRB-02: Combination of Multiple EPID Imager Layers Improves Image Quality and Tracking Performance of Low Contrast Objects

Medical Physics, Jun 1, 2015

ABSTRACT We hypothesize that an electronic portal imaging device (EPID) consisting of multiple la... more ABSTRACT We hypothesize that an electronic portal imaging device (EPID) consisting of multiple layers, each containing a scintillator coupled to amorphous silicon flat panel imager (AMFPI), increases photon detection efficiency, improving image quality and tracking accuracy of low contrast targets during radiotherapy. The prototype 4-layer imager evaluated in this study contained four individually programmable layers each with a copper-Gd₂O₂S scintillator coupled to an AMFPI with a complete set of readout electronics. The imager was placed on a Varian TrueBeam linac. A Las-Vegas phantom programmed with sinusoidal motion (Peak-to-peak amplitude=20cm, Period=3.5sec) was imaged at a frame rate of 10Hz with one to four layers activated (activation of only the top layer is equivalent to using a conventional EPID). Image quality was assessed by counting the number of visible circles, and computing the contrast-to-noise ratio (CNR) of the least visible circle (depth=0.5mm, diameter=7mm). A previously validated tracking algorithm was employed for auto-tracking. Tracking error was defined as the difference between the programmed and tracked positions of the circle. The Pearson correlation coefficient of the CNR and tracking error was also computed. Motion-induced EPID image blurring significantly reduced circle visibility. During one cycle of phantom motion, the number of visible circles ranged from 11-23, 13-24, 15-25, and 16-26 when imaged with one, two, three and four layer imagers, respectively. Compared with using only a single layer, combining 2, 3, and 4 layers increased the median CNR by factors of 1.19, 1.42, and 1.71, respectively and reduced the average tracking error from 3.32mm to 1.67mm to 1.47mm, and 0.74mm, respectively. Significant correlations (p∼10-(9)) were found between the tracking error and CNR. Combination of four amorphous silicon layers, instead of single layer, significantly improves the EPID image quality and tracking accuracy for a poorly visible object that replicates lung tumor radiotherapy conditions. The project described was supported, in part, by a grant from Varian Medical Systems, Inc., and Award No. R01CA188446-01 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

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Research paper thumbnail of TH‐EF‐BRB‐01: JUNIOR INVESTIGATOR WINNER — Novel EPID for Enhanced Contrast and Detective Quantum Efficiency

Medical Physics, 2015

Purpose:Beams‐eye‐view imaging applications such as real‐time soft‐tissue motion estimation are h... more Purpose:Beams‐eye‐view imaging applications such as real‐time soft‐tissue motion estimation are hindered by the inherently low image contrast of electronic portal imaging devices (EPID) currently in clinical use. We introduce and characterize a novel EPID that provides substantially increased detective quantum efficiency (DQE), contrast‐to‐noise ratio (CNR) and dynamic range without degradation in spatial resolution.Methods:The prototype design features a stack of four conventional EPID layers combined with low noise integrated readout electronics. Each layer consists of a copper plate, a scintillator (GdO2S2:Tb) and a photodiode/TFT‐switch (aSi:H). We characterize the prototype in terms of contrast‐to‐noise ratio (CNR), modulation transfer function (MTF) and DQE. CNR is estimated using a Las Vegas contrast phantom, presampled MTF is estimated using a slanted edge technique and the DQE is calculated from measured normalized noise power spectra (NPS) and the MTF. The prototype has be...

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Research paper thumbnail of SU-E-J-27: Shifting Multiple EPID Imager Layers to Improve Image Quality and Resolution in MV CBCT

Medical Physics, 2015

Purpose: Vertical stacking of four conventional EPID layers can improve DQE for MV-CBCT applicati... more Purpose: Vertical stacking of four conventional EPID layers can improve DQE for MV-CBCT applications. We hypothesize that shifting each layer laterally by half a pixel relative to the layer above, will improve the contrast-to-noise ratio (CNR) and image resolution. Methods: For CNR assessment, a 20 cm diameter digital phantom with 8 inserts is created. The attenuation coefficient of the phantom is similar to lung at the average energy of a 6 MV photon beam. The inserts have attenuations 1, 2…8 times of lung. One of the inserts is close to soft tissue, resembling the case of a tumor in lung. For resolution assessment, a digital phantom featuring a bar pattern is created. The phantom has an attenuation coefficient similar to soft tissue and the bars have an attenuation coefficient of calcium sulfate. A 2 MeV photon beam is attenuated through these phantoms and hits each of the four stacked detector layers. Each successive layer is shifted by half a pixel in the x only, y only, and x and y (combined) directions, respectively. Blurring and statistical noise are added to the projections. Projections from one, two, three and four layers are used for reconstruction. CNR and image resolution are evaluated and compared. Results: When projections from multiple layers are combined for reconstruction, CNR increases with the number of layers involved. CNR in reconstructions from two, three and four layers are 1.4, 1.7 and 1.99 times that from one layer. The resolution from the shifted four layer detector is also improved from a single layer. In a comparison between one layer versus four layers in this preliminary study, the resolution from four shifted layers is at least 20% better. Conclusion: Layer-shifting in a stacked EPID imager design enhances resolution as well as CNR for half scan MV-CBCT. The project described was supported, in part, by a grant from Varian Medical Systems, Inc., and Award No. R01CA188446-01 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health

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Research paper thumbnail of Organized by IEEE I&M TC-19 Technical Committee on Imaging Systems and Techniques and Tsinghua University Graduate School in ShenZehn

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Research paper thumbnail of Dispositif d'imagerie par rayons x conçu pour communiquer des donnees en temps reel par le biais d'une interface de reseau

L'invention concerne un dispositif d'imagerie par rayons x concu pour communiquer des don... more L'invention concerne un dispositif d'imagerie par rayons x concu pour communiquer des donnees images en temps reel par le biais d'une interface de reseau. Des signaux de donnees images provenant d'un ensemble de detecteur d'imagerie par rayons x issus de la conversion de photons des rayons x incidents correspondant a une image d'un sujet sont, a leur tour, convertis en un ou plusieurs signaux de donnees de reseau correspondants, tels que des signaux de gigabit ethernet.

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Research paper thumbnail of Data signal amplifier automatically controllable dynamic signal extensive

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Research paper thumbnail of A novel EPID design for enhanced contrast and detective quantum efficiency

Physics in Medicine and Biology, 2016

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Research paper thumbnail of Multiple gain ranging readout method to extend the dynamic range of amorphous silicon flat panel imagers

Medical Imaging 2004: Physics of Medical Imaging, Pts 1 and 2, 2004

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Research paper thumbnail of X-ray imaging using K edge filters (Proceedings Paper)

It is known that high dose X-ray irradiation increases the probability of cancer development in h... more It is known that high dose X-ray irradiation increases the probability of cancer development in humans. Therefore, the dose decrease at every X-ray imaging event is a major goal, especially during CT tests, where the applied dose is generally a multiple of a few single ...

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Research paper thumbnail of Improved properties of PbI x-ray imagers with tighter process control and using positive bias voltage

Proceedings of …, 2004

Vapor deposited lead iodide films show a wide range of physical attributes dependant upon fabrica... more Vapor deposited lead iodide films show a wide range of physical attributes dependant upon fabrication conditions. High density is most readily achieved with films less than 100 μm. Thicker films, with lessening density, often show lower response (gain) as charge collection ...

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Research paper thumbnail of Penetrating Radiation Systems and Applications XI (Proceedings Volume)

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Research paper thumbnail of Dual energy contrast enhanced X-ray CT characterization of malignancies from single acquisition data sets

2014 IEEE International Conference on Imaging Systems and Techniques (IST) Proceedings, 2014

Contrast agents in CT and MRI investigations have been used for obtaining better diagnosis, inclu... more Contrast agents in CT and MRI investigations have been used for obtaining better diagnosis, including whether a nodule in the breast is benign or malignant. Cone beam CT images of breast cancer nodules have been taken with iodine contrast enhancement using two CT data sets, before and after iodine contrast injection. After the CT reconstructions, by subtracting the pre-contrast HU values from those obtained with iodine contrast at the nodules, the contrast enhancement values of the suspicious nodules were obtained. This article describes a method of determining mean “quantitative imaging biomarker” values such as calibrated mean contrast concentrations of enhancement agents like iodine contrast agents in X-ray CT in segmented nodules identified using X-ray CT image data obtained in a single CT data set acquisitions instead of using two datasets (before and after contrast agent injection). This method can be applied to different organs and/or different contrast agents by using dual energy values optimized for the given cases by carefully calibrating the CT values for each energy pair.

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Research paper thumbnail of MTF characterization in 2D and 3D for a high resolution, large field of view flat panel imager for cone beam CT

The 2D and 3D modulation transfer functions (MTFs) of a custom made, large 40x30cm2 area, 600- mi... more The 2D and 3D modulation transfer functions (MTFs) of a custom made, large 40x30cm2 area, 600- micron CsI-TFT based flat panel imager having 127-micron pixellation, along with the micro-fiber scintillator structure, were characterized in detail using various techniques. The larger area detector yields a reconstructed FOV of 25cm diameter with an 80cm SID in CT mode. The MTFs were determined with 1x1 (intrinsic) binning. The 2D MTFs were determined using a 50.8 micron tungsten wire and a solid lead edge, and the 3D MTF was measured using a custom made phantom consisting of three nearly orthogonal 50.8 micron tungsten wires suspended in an acrylic cubic frame. The 2D projection data was reconstructed using an iterative OSC algorithm using 16 subsets and 5 iterations. As additional verification of the resolution, along with scatter, the Catphan® phantom was also imaged and reconstructed with identical parameters. The measured 2D MTF was ~4% using the wire technique and ~1% using the ed...

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Research paper thumbnail of Analysis of thin film fire sensors

Microelectronics Journal, 1985

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Research paper thumbnail of Super-resolution imaging in a multiple layer EPID

Biomedical physics & engineering express, 2017

A new portal imager consisting of four vertically stacked conventional electronic portal imaging ... more A new portal imager consisting of four vertically stacked conventional electronic portal imaging device (EPID) layers has been constructed in pursuit of improved detective quantum efficiency (DQE). We hypothesize that super-resolution (SR) imaging can also be achieved in such a system by shifting each layer laterally by half a pixel relative to the layer above. Super-resolution imaging will improve resolution and contrast-to-noise ratio (CNR) in megavoltage (MV) planar and cone beam computed tomography (MV-CBCT) applications. Simulations are carried out to test this hypothesis with digital phantoms. To assess planar resolution, 2 mm long iron rods with 0.3 × 0.3 mm(2) square cross-section are arranged in a grid pattern at the center of a 1 cm thick solid water. For measuring CNR in MV-CBCT, a 20 cm diameter digital phantom with 8 inserts of different electron densities is used. For measuring resolution in MV-CBCT, a digital phantom featuring a bar pattern similar to the Gammex™ phan...

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Research paper thumbnail of Technical Note: Combination of multiple EPID imager layers improves image quality and tracking performance of low contrast-to-noise objects

Medical physics, Jan 21, 2017

We hypothesized that combining multiple amorphous silicon flat panel layers increases photon dete... more We hypothesized that combining multiple amorphous silicon flat panel layers increases photon detection efficiency in an electronic portal imaging device (EPID), improving image quality and tracking accuracy of low contrast targets during radiotherapy METHODS: The prototype imager evaluated in this study contained 4 individually programmable layers each with a copper converter layer, Gd2 O2 S scintillator and active-matrix flat panel imager (AMFPI). The imager was placed on a Varian TrueBeam linac and a Las Vegas phantom programmed with sinusoidal motion (peak-to-peak amplitude=20mm, Period=3.5sec) was imaged at a frame rate of 10Hz with one to four layers activated. Number of visible circles and CNR of least visible circle (depth=0.5mm, diameter=7mm) was computed to assess the image quality of single and multiple layers. A previously validated tracking algorithm was employed for auto-tracking. Tracking error was defined as the difference between the programmed and tracked positions ...

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Research paper thumbnail of Detailed Imager Evaluation and Unique Applications of a New 20cm x 25 cm Size Mercuric Iodide Thick Film X-Ray Detector

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Research paper thumbnail of Voltage injector and detector for printed circuit board testing

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Research paper thumbnail of Reducing dark current of photoconductor using heterojunction that maintains high x-ray sensitivity

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Research paper thumbnail of Photoconductor imagers with sandwich structure

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Research paper thumbnail of TH-EF-BRB-02: Combination of Multiple EPID Imager Layers Improves Image Quality and Tracking Performance of Low Contrast Objects

Medical Physics, Jun 1, 2015

ABSTRACT We hypothesize that an electronic portal imaging device (EPID) consisting of multiple la... more ABSTRACT We hypothesize that an electronic portal imaging device (EPID) consisting of multiple layers, each containing a scintillator coupled to amorphous silicon flat panel imager (AMFPI), increases photon detection efficiency, improving image quality and tracking accuracy of low contrast targets during radiotherapy. The prototype 4-layer imager evaluated in this study contained four individually programmable layers each with a copper-Gd₂O₂S scintillator coupled to an AMFPI with a complete set of readout electronics. The imager was placed on a Varian TrueBeam linac. A Las-Vegas phantom programmed with sinusoidal motion (Peak-to-peak amplitude=20cm, Period=3.5sec) was imaged at a frame rate of 10Hz with one to four layers activated (activation of only the top layer is equivalent to using a conventional EPID). Image quality was assessed by counting the number of visible circles, and computing the contrast-to-noise ratio (CNR) of the least visible circle (depth=0.5mm, diameter=7mm). A previously validated tracking algorithm was employed for auto-tracking. Tracking error was defined as the difference between the programmed and tracked positions of the circle. The Pearson correlation coefficient of the CNR and tracking error was also computed. Motion-induced EPID image blurring significantly reduced circle visibility. During one cycle of phantom motion, the number of visible circles ranged from 11-23, 13-24, 15-25, and 16-26 when imaged with one, two, three and four layer imagers, respectively. Compared with using only a single layer, combining 2, 3, and 4 layers increased the median CNR by factors of 1.19, 1.42, and 1.71, respectively and reduced the average tracking error from 3.32mm to 1.67mm to 1.47mm, and 0.74mm, respectively. Significant correlations (p∼10-(9)) were found between the tracking error and CNR. Combination of four amorphous silicon layers, instead of single layer, significantly improves the EPID image quality and tracking accuracy for a poorly visible object that replicates lung tumor radiotherapy conditions. The project described was supported, in part, by a grant from Varian Medical Systems, Inc., and Award No. R01CA188446-01 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

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Research paper thumbnail of TH‐EF‐BRB‐01: JUNIOR INVESTIGATOR WINNER — Novel EPID for Enhanced Contrast and Detective Quantum Efficiency

Medical Physics, 2015

Purpose:Beams‐eye‐view imaging applications such as real‐time soft‐tissue motion estimation are h... more Purpose:Beams‐eye‐view imaging applications such as real‐time soft‐tissue motion estimation are hindered by the inherently low image contrast of electronic portal imaging devices (EPID) currently in clinical use. We introduce and characterize a novel EPID that provides substantially increased detective quantum efficiency (DQE), contrast‐to‐noise ratio (CNR) and dynamic range without degradation in spatial resolution.Methods:The prototype design features a stack of four conventional EPID layers combined with low noise integrated readout electronics. Each layer consists of a copper plate, a scintillator (GdO2S2:Tb) and a photodiode/TFT‐switch (aSi:H). We characterize the prototype in terms of contrast‐to‐noise ratio (CNR), modulation transfer function (MTF) and DQE. CNR is estimated using a Las Vegas contrast phantom, presampled MTF is estimated using a slanted edge technique and the DQE is calculated from measured normalized noise power spectra (NPS) and the MTF. The prototype has be...

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Research paper thumbnail of SU-E-J-27: Shifting Multiple EPID Imager Layers to Improve Image Quality and Resolution in MV CBCT

Medical Physics, 2015

Purpose: Vertical stacking of four conventional EPID layers can improve DQE for MV-CBCT applicati... more Purpose: Vertical stacking of four conventional EPID layers can improve DQE for MV-CBCT applications. We hypothesize that shifting each layer laterally by half a pixel relative to the layer above, will improve the contrast-to-noise ratio (CNR) and image resolution. Methods: For CNR assessment, a 20 cm diameter digital phantom with 8 inserts is created. The attenuation coefficient of the phantom is similar to lung at the average energy of a 6 MV photon beam. The inserts have attenuations 1, 2…8 times of lung. One of the inserts is close to soft tissue, resembling the case of a tumor in lung. For resolution assessment, a digital phantom featuring a bar pattern is created. The phantom has an attenuation coefficient similar to soft tissue and the bars have an attenuation coefficient of calcium sulfate. A 2 MeV photon beam is attenuated through these phantoms and hits each of the four stacked detector layers. Each successive layer is shifted by half a pixel in the x only, y only, and x and y (combined) directions, respectively. Blurring and statistical noise are added to the projections. Projections from one, two, three and four layers are used for reconstruction. CNR and image resolution are evaluated and compared. Results: When projections from multiple layers are combined for reconstruction, CNR increases with the number of layers involved. CNR in reconstructions from two, three and four layers are 1.4, 1.7 and 1.99 times that from one layer. The resolution from the shifted four layer detector is also improved from a single layer. In a comparison between one layer versus four layers in this preliminary study, the resolution from four shifted layers is at least 20% better. Conclusion: Layer-shifting in a stacked EPID imager design enhances resolution as well as CNR for half scan MV-CBCT. The project described was supported, in part, by a grant from Varian Medical Systems, Inc., and Award No. R01CA188446-01 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health

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Research paper thumbnail of Organized by IEEE I&M TC-19 Technical Committee on Imaging Systems and Techniques and Tsinghua University Graduate School in ShenZehn

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Research paper thumbnail of Dispositif d'imagerie par rayons x conçu pour communiquer des donnees en temps reel par le biais d'une interface de reseau

L'invention concerne un dispositif d'imagerie par rayons x concu pour communiquer des don... more L'invention concerne un dispositif d'imagerie par rayons x concu pour communiquer des donnees images en temps reel par le biais d'une interface de reseau. Des signaux de donnees images provenant d'un ensemble de detecteur d'imagerie par rayons x issus de la conversion de photons des rayons x incidents correspondant a une image d'un sujet sont, a leur tour, convertis en un ou plusieurs signaux de donnees de reseau correspondants, tels que des signaux de gigabit ethernet.

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Research paper thumbnail of Data signal amplifier automatically controllable dynamic signal extensive

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A novel EPID design for enhanced contrast and detective quantum efficiency

Physics in Medicine and Biology, 2016

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Research paper thumbnail of Multiple gain ranging readout method to extend the dynamic range of amorphous silicon flat panel imagers

Medical Imaging 2004: Physics of Medical Imaging, Pts 1 and 2, 2004

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Research paper thumbnail of X-ray imaging using K edge filters (Proceedings Paper)

It is known that high dose X-ray irradiation increases the probability of cancer development in h... more It is known that high dose X-ray irradiation increases the probability of cancer development in humans. Therefore, the dose decrease at every X-ray imaging event is a major goal, especially during CT tests, where the applied dose is generally a multiple of a few single ...

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Research paper thumbnail of Improved properties of PbI x-ray imagers with tighter process control and using positive bias voltage

Proceedings of …, 2004

Vapor deposited lead iodide films show a wide range of physical attributes dependant upon fabrica... more Vapor deposited lead iodide films show a wide range of physical attributes dependant upon fabrication conditions. High density is most readily achieved with films less than 100 μm. Thicker films, with lessening density, often show lower response (gain) as charge collection ...

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Research paper thumbnail of Penetrating Radiation Systems and Applications XI (Proceedings Volume)

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dual energy contrast enhanced X-ray CT characterization of malignancies from single acquisition data sets

2014 IEEE International Conference on Imaging Systems and Techniques (IST) Proceedings, 2014

Contrast agents in CT and MRI investigations have been used for obtaining better diagnosis, inclu... more Contrast agents in CT and MRI investigations have been used for obtaining better diagnosis, including whether a nodule in the breast is benign or malignant. Cone beam CT images of breast cancer nodules have been taken with iodine contrast enhancement using two CT data sets, before and after iodine contrast injection. After the CT reconstructions, by subtracting the pre-contrast HU values from those obtained with iodine contrast at the nodules, the contrast enhancement values of the suspicious nodules were obtained. This article describes a method of determining mean “quantitative imaging biomarker” values such as calibrated mean contrast concentrations of enhancement agents like iodine contrast agents in X-ray CT in segmented nodules identified using X-ray CT image data obtained in a single CT data set acquisitions instead of using two datasets (before and after contrast agent injection). This method can be applied to different organs and/or different contrast agents by using dual energy values optimized for the given cases by carefully calibrating the CT values for each energy pair.

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Research paper thumbnail of MTF characterization in 2D and 3D for a high resolution, large field of view flat panel imager for cone beam CT

The 2D and 3D modulation transfer functions (MTFs) of a custom made, large 40x30cm2 area, 600- mi... more The 2D and 3D modulation transfer functions (MTFs) of a custom made, large 40x30cm2 area, 600- micron CsI-TFT based flat panel imager having 127-micron pixellation, along with the micro-fiber scintillator structure, were characterized in detail using various techniques. The larger area detector yields a reconstructed FOV of 25cm diameter with an 80cm SID in CT mode. The MTFs were determined with 1x1 (intrinsic) binning. The 2D MTFs were determined using a 50.8 micron tungsten wire and a solid lead edge, and the 3D MTF was measured using a custom made phantom consisting of three nearly orthogonal 50.8 micron tungsten wires suspended in an acrylic cubic frame. The 2D projection data was reconstructed using an iterative OSC algorithm using 16 subsets and 5 iterations. As additional verification of the resolution, along with scatter, the Catphan® phantom was also imaged and reconstructed with identical parameters. The measured 2D MTF was ~4% using the wire technique and ~1% using the ed...

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Research paper thumbnail of Analysis of thin film fire sensors

Microelectronics Journal, 1985

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Super-resolution imaging in a multiple layer EPID

Biomedical physics & engineering express, 2017

A new portal imager consisting of four vertically stacked conventional electronic portal imaging ... more A new portal imager consisting of four vertically stacked conventional electronic portal imaging device (EPID) layers has been constructed in pursuit of improved detective quantum efficiency (DQE). We hypothesize that super-resolution (SR) imaging can also be achieved in such a system by shifting each layer laterally by half a pixel relative to the layer above. Super-resolution imaging will improve resolution and contrast-to-noise ratio (CNR) in megavoltage (MV) planar and cone beam computed tomography (MV-CBCT) applications. Simulations are carried out to test this hypothesis with digital phantoms. To assess planar resolution, 2 mm long iron rods with 0.3 × 0.3 mm(2) square cross-section are arranged in a grid pattern at the center of a 1 cm thick solid water. For measuring CNR in MV-CBCT, a 20 cm diameter digital phantom with 8 inserts of different electron densities is used. For measuring resolution in MV-CBCT, a digital phantom featuring a bar pattern similar to the Gammex™ phan...

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Research paper thumbnail of Technical Note: Combination of multiple EPID imager layers improves image quality and tracking performance of low contrast-to-noise objects

Medical physics, Jan 21, 2017

We hypothesized that combining multiple amorphous silicon flat panel layers increases photon dete... more We hypothesized that combining multiple amorphous silicon flat panel layers increases photon detection efficiency in an electronic portal imaging device (EPID), improving image quality and tracking accuracy of low contrast targets during radiotherapy METHODS: The prototype imager evaluated in this study contained 4 individually programmable layers each with a copper converter layer, Gd2 O2 S scintillator and active-matrix flat panel imager (AMFPI). The imager was placed on a Varian TrueBeam linac and a Las Vegas phantom programmed with sinusoidal motion (peak-to-peak amplitude=20mm, Period=3.5sec) was imaged at a frame rate of 10Hz with one to four layers activated. Number of visible circles and CNR of least visible circle (depth=0.5mm, diameter=7mm) was computed to assess the image quality of single and multiple layers. A previously validated tracking algorithm was employed for auto-tracking. Tracking error was defined as the difference between the programmed and tracked positions ...

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Research paper thumbnail of Detailed Imager Evaluation and Unique Applications of a New 20cm x 25 cm Size Mercuric Iodide Thick Film X-Ray Detector

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Research paper thumbnail of Voltage injector and detector for printed circuit board testing

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Research paper thumbnail of Reducing dark current of photoconductor using heterojunction that maintains high x-ray sensitivity

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Photoconductor imagers with sandwich structure

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