Uri Shreter - Academia.edu (original) (raw)
Papers by Uri Shreter
Proceedings of SPIE, Mar 8, 2007
We present the results of dose and image quality performance evaluation of a novel, prospective E... more We present the results of dose and image quality performance evaluation of a novel, prospective ECG-gated Coronary CT Angiography acquisition mode (SnapShot Pulse, LightSpeed VCT-XT scanner, GE Healthcare, Waukesha, WI), and compare it to conventional retrospective ECG gated helical acquisition in clinical and phantom studies. Image quality phantoms were used to measure noise, slice sensitivity profile, in-plane resolution, low contrast
Chest, Oct 1, 2009
PURPOSE: Purpose: To evaluate the spatial accuracy and performance of a stereotactic computer gui... more PURPOSE: Purpose: To evaluate the spatial accuracy and performance of a stereotactic computer guidance optical needle tracking system in CT guided lung biopsies.The purpose of this study is to report on the evaluation of a recently developed, optical stereotactic tracking and guiding system. DISCLOSURE: Yehuda Schwarz, Grant monies (from industry related sources) Recived a grant for the reseach from Activiews Ltd.; Shareholder Received future options if the company goes to the stock market; Consultant fee, speaker bureau, advisory committee, etc.
Journal of Vascular and Interventional Radiology, Apr 1, 2013
Learning Objectives: 1. Identify various clinical conditions which cause pelvic venous dilatation... more Learning Objectives: 1. Identify various clinical conditions which cause pelvic venous dilatation and/or obstruction. 2. Describe the anatomic abnormality associated with each clinical condition and provide MR and correlative conventional angiographic examples of each abnormality. 3. Discuss the utility of MR angiography in planning potential endovascular interventions for such venous abnormalities, with a specific focus on the use of blood pool contrast agents in MR angiography. Background: Recently developed MR blood pool contrast agents, such as gadofoscecet (Ablavar TM), have markedly less extracellular distribution than their predecessors, a property that allows for steady-state high-resolution imaging of veins and complex venous lesions. In this presentation, we will illustrate how gadofoscecet use enhances the MR characterization of venous anomalies and abnormalities. Improved MR characterization facilitates not only proper diagnosis of but also the appropriate planning for endovascular interventions which treat pelvic vein obstruction. Clinical Findings/Procedure Details: We will present MR and correlative conventional angiography examples of venous anomalies and abnormalities resulting in pelvic venous dilatation and/or obstruction, including: congenital caval anomalies, inferior vena cava stenosis stenosis from chronic iliocaval thrombosis, May-Thurner (Cockett) syndrome, nutcracker syndrome, gonadal vein reflux, venous obstruction secondary to mass effect from extrinsic anatomic structures. Conclusion and/or Teaching Points: (1) Pelvic venous dilation is commonly caused by venous anomalies or abnormalities which can be diagnosed noninvasively using MR angiography. (2) MR blood pool contrast agents, such as gadofoscecet (Ablavar TM), enhance MR characterization of venous anomalies and abnormalities by opacifying their full geographic extent as well as providing information regarding directionality of venous flow. (3) MR angiography is a useful, if not critical, tool in pre-procedure planning of endovascular treatment of pelvic vein obstruction.
The Lung Image Database Consortium image collection (LIDC-IDRI) consists of diagnostic and lung c... more The Lung Image Database Consortium image collection (LIDC-IDRI) consists of diagnostic and lung cancer screening thoracic computed tomography (CT) scans with marked-up annotated lesions. It is a web-accessible international resource for development, training, and evaluation of computer-assisted diagnostic (CAD) methods for lung cancer detection and diagnosis. Initiated by the National Cancer Institute (NCI), further advanced by the Foundation for the National Institutes of Health (FNIH), and accompanied by the Food and Drug Administration (FDA) through active participation, this public-private partnership demonstrates the success of a consortium founded on a consensus-based process. Seven academic centers and eight medical imaging companies collaborated to create this data set which contains 1018 cases. Each subject includes images from a clinical thoracic CT scan and an associated XML file that records the results of a two-phase image annotation process performed by four experience...
Molecular Physics, 2021
The main point of the paper is to take the explicit motivic Chabauty-Kim method developed in pape... more The main point of the paper is to take the explicit motivic Chabauty-Kim method developed in papers of Dan-Cohen-Wewers and Dan-Cohen and the author and make it work for non-rational curves. In particular, we calculate the abstract form of an element of the Chabauty-Kim ideal for Z[1/ℓ]-points on a punctured elliptic curve, and lay some groundwork for certain kinds of higher genus curves. For this purpose, we develop an "explicit Tannakian Chabauty-Kim method" using Q ℓ-Tannakian categories of Galois representations in place of Q-linear motives. In future work, we intend to use this method to explicitly apply the Chabauty-Kim method to a curve of positive genus in a situation where Quadratic Chabauty does not apply.
L'invention concerne un procede de modification d'une coupe d'image plane dans un tom... more L'invention concerne un procede de modification d'une coupe d'image plane dans un tomodensitometre presentant un angle de reconstruction predetermine et consistant a reconstruire une image de la coupe au moyen de donnees initiales d'attenuation de rayons X acquises le long d'un secteur de trajet initial de scintigraphie, a acquerir des donnees additionnelles d'attenuation de rayons X le long d'un autre secteur de trajet de scintigraphie, a proximite de la position axiale de la coupe, le secteur ayant un degre angulaire sensiblement inferieur a l'angle de reconstruction, et a modifier l'image afin de produire une image modifiee de la coupe, en fonction des donnees d'attenuation supplementaires.
: Ion mixing and sputtering are influenced by the same transport mechanisms during irradiation. B... more : Ion mixing and sputtering are influenced by the same transport mechanisms during irradiation. Both prompt and delayed processes are expected to affect mixing as well as sputtering. It is known that mixing of a Cr layer on Si is strongly temperature-dependent above room temperature. CrSi2 was chosen therefore for the investigation of temperature effects in sputtering. Measurements of sputtering yields and composition profiles have been carried out using backscattering spectrometry for samples of CrSi2 on Si irradiated with 200 keV Xe ions. When the CrSi2 layer is thinner than the ion range, the sputtering yield ratio of Si to Cr increases from 3.5 for room temperature irradiation to 65 at 290 degrees C.
Systeme d'imagerie medicale servant a effectuer une operation guidee par l'image sur un p... more Systeme d'imagerie medicale servant a effectuer une operation guidee par l'image sur un patient et procede servant a mettre en application cette operation. Ce systeme comprend un appareil d'imagerie medicale, tel qu'un scanner CT (tomographie par ordinateur), un dispositif d'imagerie par resonance magnetique ou un dispositif d'imagerie par ultrasons, afin d'obtenir des images volumetriques du patient. On determine, par l'intermediaire de techniques de planification d'intervention, la procedure d'intervention sur le patient au moyen de ces images volumetriques. Un ensemble bras mecanique situe a proximite du dispositif d'imagerie medicale execute cette procedure d'intervention. Cet ensemble bras mecanique comporte un support de base, une extremite distale, une pluralite de segments de bras, ainsi qu'une pluralite d'articulations entre ces segments de bras afin d'executer l'intervention. Un terminal est place au niveau de...
1983 Eighth International Conference on Infrared and Millimeter Waves, 1983
Monolithic GaAs Schottky diode imaging arrays have been demonstrated at 69 and 94 GHz. In the 94 ... more Monolithic GaAs Schottky diode imaging arrays have been demonstrated at 69 and 94 GHz. In the 94 GHz experiments, the diodes are fabricated by a self-aligning technique on semi-insulating GaAs and are isolated by a combination of a mesa-etch process and proton-bombardment. The series resistance is 20 ω and the estimated capacitance is 15–20 fF. The antennas are planar bow-ties, and power is coupled in through a quartz lens placed on the back of the GaAs substrate. The wafer is lapped to 90 μm thick to eliminate losses to substrate modes. The measured system responsivity is 330 V/W. The 69 GHz diodes are made by a non-self-aligned process, and a silicon substrate lens is used.
Bilayers of Si/metal (metal on top) and metal/Si (Si on top) were annealed in vacuum to produce t... more Bilayers of Si/metal (metal on top) and metal/Si (Si on top) were annealed in vacuum to produce the Si/silicide/metal and metal/silicide/Si configurations, respectively. The sandwich structures were then irradiated with Xe ions of energies ranging from 125 to 300 keV such that the Xe ions traverse only one of the two interfaces (metal-silicide or silicide-Si). In the case of CrSi2, irradiation above 150°C induces further and laterally uniform growth of a stoichiometric layer of silicide, but only when the Cr/CrSi2 interface is traversed, not when the other interface is traversed. We conclude that the formation of CrSi2 is an interface-limited process, which is consistent with the linear time dependence of the growth of CrSi2 under thermal annealing, and that the limiting reaction occurs at the Cr/ CrSi2 interface. On the other hand, in TaSi2 for temperatures up to 500°C, and in Pt2Si at room temperature, Xe ions penetrating through only one of either of the two interfaces does not i...
Proceedings of Spie the International Society For Optical Engineering, Mar 1, 2007
We present the results of dose and image quality performance evaluation of a novel, prospective E... more We present the results of dose and image quality performance evaluation of a novel, prospective ECG-gated Coronary CT Angiography acquisition mode (SnapShot Pulse, LightSpeed VCT-XT scanner, GE Healthcare, Waukesha, WI), and compare it to conventional retrospective ECG gated helical acquisition in clinical and phantom studies. Image quality phantoms were used to measure noise, slice sensitivity profile, in-plane resolution, low contrast
Proceedings of SPIE, Mar 8, 2007
We present the results of dose and image quality performance evaluation of a novel, prospective E... more We present the results of dose and image quality performance evaluation of a novel, prospective ECG-gated Coronary CT Angiography acquisition mode (SnapShot Pulse, LightSpeed VCT-XT scanner, GE Healthcare, Waukesha, WI), and compare it to conventional retrospective ECG gated helical acquisition in clinical and phantom studies. Image quality phantoms were used to measure noise, slice sensitivity profile, in-plane resolution, low contrast
Chest, Oct 1, 2009
PURPOSE: Purpose: To evaluate the spatial accuracy and performance of a stereotactic computer gui... more PURPOSE: Purpose: To evaluate the spatial accuracy and performance of a stereotactic computer guidance optical needle tracking system in CT guided lung biopsies.The purpose of this study is to report on the evaluation of a recently developed, optical stereotactic tracking and guiding system. DISCLOSURE: Yehuda Schwarz, Grant monies (from industry related sources) Recived a grant for the reseach from Activiews Ltd.; Shareholder Received future options if the company goes to the stock market; Consultant fee, speaker bureau, advisory committee, etc.
Journal of Vascular and Interventional Radiology, Apr 1, 2013
Learning Objectives: 1. Identify various clinical conditions which cause pelvic venous dilatation... more Learning Objectives: 1. Identify various clinical conditions which cause pelvic venous dilatation and/or obstruction. 2. Describe the anatomic abnormality associated with each clinical condition and provide MR and correlative conventional angiographic examples of each abnormality. 3. Discuss the utility of MR angiography in planning potential endovascular interventions for such venous abnormalities, with a specific focus on the use of blood pool contrast agents in MR angiography. Background: Recently developed MR blood pool contrast agents, such as gadofoscecet (Ablavar TM), have markedly less extracellular distribution than their predecessors, a property that allows for steady-state high-resolution imaging of veins and complex venous lesions. In this presentation, we will illustrate how gadofoscecet use enhances the MR characterization of venous anomalies and abnormalities. Improved MR characterization facilitates not only proper diagnosis of but also the appropriate planning for endovascular interventions which treat pelvic vein obstruction. Clinical Findings/Procedure Details: We will present MR and correlative conventional angiography examples of venous anomalies and abnormalities resulting in pelvic venous dilatation and/or obstruction, including: congenital caval anomalies, inferior vena cava stenosis stenosis from chronic iliocaval thrombosis, May-Thurner (Cockett) syndrome, nutcracker syndrome, gonadal vein reflux, venous obstruction secondary to mass effect from extrinsic anatomic structures. Conclusion and/or Teaching Points: (1) Pelvic venous dilation is commonly caused by venous anomalies or abnormalities which can be diagnosed noninvasively using MR angiography. (2) MR blood pool contrast agents, such as gadofoscecet (Ablavar TM), enhance MR characterization of venous anomalies and abnormalities by opacifying their full geographic extent as well as providing information regarding directionality of venous flow. (3) MR angiography is a useful, if not critical, tool in pre-procedure planning of endovascular treatment of pelvic vein obstruction.
The Lung Image Database Consortium image collection (LIDC-IDRI) consists of diagnostic and lung c... more The Lung Image Database Consortium image collection (LIDC-IDRI) consists of diagnostic and lung cancer screening thoracic computed tomography (CT) scans with marked-up annotated lesions. It is a web-accessible international resource for development, training, and evaluation of computer-assisted diagnostic (CAD) methods for lung cancer detection and diagnosis. Initiated by the National Cancer Institute (NCI), further advanced by the Foundation for the National Institutes of Health (FNIH), and accompanied by the Food and Drug Administration (FDA) through active participation, this public-private partnership demonstrates the success of a consortium founded on a consensus-based process. Seven academic centers and eight medical imaging companies collaborated to create this data set which contains 1018 cases. Each subject includes images from a clinical thoracic CT scan and an associated XML file that records the results of a two-phase image annotation process performed by four experience...
Molecular Physics, 2021
The main point of the paper is to take the explicit motivic Chabauty-Kim method developed in pape... more The main point of the paper is to take the explicit motivic Chabauty-Kim method developed in papers of Dan-Cohen-Wewers and Dan-Cohen and the author and make it work for non-rational curves. In particular, we calculate the abstract form of an element of the Chabauty-Kim ideal for Z[1/ℓ]-points on a punctured elliptic curve, and lay some groundwork for certain kinds of higher genus curves. For this purpose, we develop an "explicit Tannakian Chabauty-Kim method" using Q ℓ-Tannakian categories of Galois representations in place of Q-linear motives. In future work, we intend to use this method to explicitly apply the Chabauty-Kim method to a curve of positive genus in a situation where Quadratic Chabauty does not apply.
L'invention concerne un procede de modification d'une coupe d'image plane dans un tom... more L'invention concerne un procede de modification d'une coupe d'image plane dans un tomodensitometre presentant un angle de reconstruction predetermine et consistant a reconstruire une image de la coupe au moyen de donnees initiales d'attenuation de rayons X acquises le long d'un secteur de trajet initial de scintigraphie, a acquerir des donnees additionnelles d'attenuation de rayons X le long d'un autre secteur de trajet de scintigraphie, a proximite de la position axiale de la coupe, le secteur ayant un degre angulaire sensiblement inferieur a l'angle de reconstruction, et a modifier l'image afin de produire une image modifiee de la coupe, en fonction des donnees d'attenuation supplementaires.
: Ion mixing and sputtering are influenced by the same transport mechanisms during irradiation. B... more : Ion mixing and sputtering are influenced by the same transport mechanisms during irradiation. Both prompt and delayed processes are expected to affect mixing as well as sputtering. It is known that mixing of a Cr layer on Si is strongly temperature-dependent above room temperature. CrSi2 was chosen therefore for the investigation of temperature effects in sputtering. Measurements of sputtering yields and composition profiles have been carried out using backscattering spectrometry for samples of CrSi2 on Si irradiated with 200 keV Xe ions. When the CrSi2 layer is thinner than the ion range, the sputtering yield ratio of Si to Cr increases from 3.5 for room temperature irradiation to 65 at 290 degrees C.
Systeme d'imagerie medicale servant a effectuer une operation guidee par l'image sur un p... more Systeme d'imagerie medicale servant a effectuer une operation guidee par l'image sur un patient et procede servant a mettre en application cette operation. Ce systeme comprend un appareil d'imagerie medicale, tel qu'un scanner CT (tomographie par ordinateur), un dispositif d'imagerie par resonance magnetique ou un dispositif d'imagerie par ultrasons, afin d'obtenir des images volumetriques du patient. On determine, par l'intermediaire de techniques de planification d'intervention, la procedure d'intervention sur le patient au moyen de ces images volumetriques. Un ensemble bras mecanique situe a proximite du dispositif d'imagerie medicale execute cette procedure d'intervention. Cet ensemble bras mecanique comporte un support de base, une extremite distale, une pluralite de segments de bras, ainsi qu'une pluralite d'articulations entre ces segments de bras afin d'executer l'intervention. Un terminal est place au niveau de...
1983 Eighth International Conference on Infrared and Millimeter Waves, 1983
Monolithic GaAs Schottky diode imaging arrays have been demonstrated at 69 and 94 GHz. In the 94 ... more Monolithic GaAs Schottky diode imaging arrays have been demonstrated at 69 and 94 GHz. In the 94 GHz experiments, the diodes are fabricated by a self-aligning technique on semi-insulating GaAs and are isolated by a combination of a mesa-etch process and proton-bombardment. The series resistance is 20 ω and the estimated capacitance is 15–20 fF. The antennas are planar bow-ties, and power is coupled in through a quartz lens placed on the back of the GaAs substrate. The wafer is lapped to 90 μm thick to eliminate losses to substrate modes. The measured system responsivity is 330 V/W. The 69 GHz diodes are made by a non-self-aligned process, and a silicon substrate lens is used.
Bilayers of Si/metal (metal on top) and metal/Si (Si on top) were annealed in vacuum to produce t... more Bilayers of Si/metal (metal on top) and metal/Si (Si on top) were annealed in vacuum to produce the Si/silicide/metal and metal/silicide/Si configurations, respectively. The sandwich structures were then irradiated with Xe ions of energies ranging from 125 to 300 keV such that the Xe ions traverse only one of the two interfaces (metal-silicide or silicide-Si). In the case of CrSi2, irradiation above 150°C induces further and laterally uniform growth of a stoichiometric layer of silicide, but only when the Cr/CrSi2 interface is traversed, not when the other interface is traversed. We conclude that the formation of CrSi2 is an interface-limited process, which is consistent with the linear time dependence of the growth of CrSi2 under thermal annealing, and that the limiting reaction occurs at the Cr/ CrSi2 interface. On the other hand, in TaSi2 for temperatures up to 500°C, and in Pt2Si at room temperature, Xe ions penetrating through only one of either of the two interfaces does not i...
Proceedings of Spie the International Society For Optical Engineering, Mar 1, 2007
We present the results of dose and image quality performance evaluation of a novel, prospective E... more We present the results of dose and image quality performance evaluation of a novel, prospective ECG-gated Coronary CT Angiography acquisition mode (SnapShot Pulse, LightSpeed VCT-XT scanner, GE Healthcare, Waukesha, WI), and compare it to conventional retrospective ECG gated helical acquisition in clinical and phantom studies. Image quality phantoms were used to measure noise, slice sensitivity profile, in-plane resolution, low contrast