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Michael V. Knopp - One of the best experts on this subject based on the ideXlab platform.
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Feasibility demonstration of imaging in vivo biodistribution of Yttrium-90 microspheres after radioembolization with a Digital Detector PET/CT system.
The Journal of Nuclear Medicine, 2015Co-Authors: Chadwick Wright, Jun Zhang, Katherine Binzel, Evan Wuthrick, Piotr Maniawski, Michael V. KnoppAbstract:1241 Objectives To assess the clinical feasibility of next generation Digital PET Detector technology for imaging Yttrium-90 internal pair production in vivo following radioembolization and compare to existing conventional photomultipler Detector PET/CT technology. Methods A next-generation, solid-state, Digital PET/CT system (Vereos TF 64, Philips Healthcare) is being used to image patients following Yttrium-90 microsphere radioembolization and compare its image characteristics, by intra-individual comparison, with a conventional photomultiplier Detector time-of-flight PET/CT (Gemini TF 64, Philips Healthcare). In addition, true coincident event rates corresponding to Yttrium-90’s internal pair production were normalized to the acquisition bed volume and total image volume for both PET/CT systems and compared. Results When compared with conventional PET/CT, Digital detection of Yttrium-90’s internal pair production also produced evaluable images for qualitatively and quantitatively assessing Yttrium-90 biodistribution throughout the liver. Furthermore, the normalized total true coincident event rate was higher for the Digital PET/CT. Conclusions The initial evidence demonstrates that 90Y internal pair production can be readily imaged in vivo with Digital Detector technologies at least equivalent to conventional PET/CT. It appears feasible that reduced acquisition times may be possible without significant impact on subsequent quantification of Yttrium-90 activity. Research Support This research was supported by the Ohio Third Frontier ODSA TECH 09-028 TECH 10-012 and TECH 13-060
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Intraindividual Evaluation of Low Dose Iterative CT Compared to Conventional CT for PET Attenuation Correction and Clinical Diagnostic Image Quality: Validation for A Next Generation Digital Detector PET/CT System
The Journal of Nuclear Medicine, 2015Co-Authors: Jun Zhang, Chadwick Wright, Katherine Binzel, Amanda M. Agnew, Philip Bardos, Xiaoli Liu, Karen Briley, Michael V. KnoppAbstract:1699 Objectives To evaluate CT dose response and the capability of low dose CT using iterative reconstruction compared to conventional CT for PET AC and satisfying clinical diagnostic CT image quality (IQ) on a next generation Digital PET/CT system Methods A pre-commercial release Digital Detector PET/CT system (Vereos TF 64, Philips Healthcare, Cleveland) was evaluated and compared to a conventional PET/CT system (Gemini TF 64). A combined clinical & cadaver trial was initiated for optimizing CT dose response and clinical demonstration. CT sweeps of 5 cadavers (180±13cm) were scanned on Vereos in arms up & down at 6 exposures (150, 100, 80, 50, 30 & 15mAs) and 3 energies (120, 100 & 80kV). PET/CT of 15 oncology patients (1.7±0.1m) were scanned with higher CT dose (164mAs) on Gemini vs lower CT dose (50mAs) on Vereos. Vereos CT was reconstructed w & w/o iterative (iDose) tech. Blinded image reviews were performed by radiologists & physicists. Quantitative analysis in HU on cadaver CTs was analyzed by image subtraction. Effective dose equivalent (EDE) for all subjects were compared Results The cadaver studies revealed the lowest acceptable dose (8.9±0.8mSv EDE) at 50mAs/120kV using iDose whcih led to ~66% dose reduction compared to the conventional approach. No significant differences in CT HU were found (p>0.05) which led to Conclusions Low dose CT (50mAs/120kV) with iterative iDose reconstruction presented equivalent image quality in clinical patients by intraindividual comparison to conventional CT (164mAs/120kV) while reducing EDE by 66%. Low dose, iterative reconstructed CT can be fully implemented in the next generation Vereos PET/CT Research Support Ohio Third Frontier Innovation Platform grant TECH 10-012 and 13-060
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3d activity mapping of yttrium 90 interventional radioembolization for dose verification using a solid state Digital pet Detector system
The Journal of Nuclear Medicine, 2015Co-Authors: Jun Zhang, Chadwick Wright, Katherine Binzel, Evan Wuthrick, Piotr Maniawski, Michael V. KnoppAbstract:1240 Objectives As PET appears to be more quantitatively correct than bremsstrahlung SPECT/CT and with the availability of improved capabilities of Digital Detector counting, we intend to develop and demonstrate the ability of quantitatively driven uptake contouring of Yttrium-90 to guide verification of dose delivery using a Digital Detector PET/CT system Methods Interventional targeted radiotherapy with Yttrium-90 microspheres is actively being used in patient care of unresectable liver malignancies and/or metastases. The verification of correct dose delivery post radioembolization remains a current challenge for patient management. Current standard imaging is post-procedural bremsstrahlung scintigraphy and SPECT/CT. We are investigationally using a next-generation, solid-state, Digital PET/CT system (Vereos TF 64, Philips Healthcare) to image patients after Yttrium-90 microsphere radioembolization. Quantitatively based contouring is being performed and compared to the pre-therapeutic dose planning Results Quantitative driven uptake contouring of microsphere deposition in the liver using Digital PET is feasible. The improved spatial and quantitative accuracy of PET revealed more precise localization of its distribution within the treatment area than bremsstrahlung imaging. A 3D dose contouring appears to be most appropriate due to the more heterogeneous distribution observable by PET. Generation of 3D uptake contouring profiles (10-90th percentile of liver volume SUVMax) was feasible and enables further development of isocontour dose profiles Conclusions This ongoing trial following patients that are receiving standard of care bremsstrahlung SPECT is demonstrating that Digital Detector PET/CT is able to provide improved spatial and quantitative accuracy of microsphere deposition and appears promising to be a preferable methodology to verify Yttrium-90 dose delivery Research Support This project was enabled by the Ohio Third Frontier Scholars, Wright Project and Innovation Platform project grants, the Wright Center of Innovation in Biomedical Imaging and Philips Healthcare providing the investigational pre-commercial release system. U24 IROC grant support
Jan Persliden - One of the best experts on this subject based on the ideXlab platform.
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Optimizing the tube potential for lumbar spine radiography with a flat-panel Digital Detector
The British journal of radiology, 2009Co-Authors: Håkan Geijer, Eva Norrman, Jan PerslidenAbstract:The purpose of this study was to find the optimal settings for lumbar spine radiography with a flat-panel Detector. A CDRAD contrast-detail phantom was imaged at various tube potentials, system speeds and filtration settings. Factorial experiments yielded a range of optimized exposure settings, which were submitted to visual grading analysis with images of an Alderson phantom. The first optimized settings involved a system speed increase from 400 to 800. For anteroposterior projection, the optimal tube potential was reduced from the default of 77 kV to 60 kV to give the best image quality without increasing the effective dose, or to 66 kV to give the lowest dose without reducing image quality. For lateral projection, the tube potential was similarly reduced from the default of 90 kV to 70 kV or 77 kV. Visual grading analysis confirmed the results, with significantly better image quality when optimizing for image quality. The study thus shows that the tube potential can be reduced as long as the system speed is increased simultaneously. This leads to a lower effective dose and/or increased image quality depending on the settings chosen. The factorial experiments provided a powerful way to evaluate several parameters concomitantly.
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Varied tube potential with constant effective dose at lumbar spine radiography using a flat-panel Digital Detector
Radiation protection dosimetry, 2005Co-Authors: Håkan Geijer, Jan PerslidenAbstract:The purpose of the study was to evaluate the image quality at different tube potential (kV) settings using anteroposterior lumbar spine radiography as a model. An Alderson phantom was used with a flat-panel Detector. The tube potential varied between 48 and 125 kV while the tube charge (mAs) was adjusted to keep an effective dose of 0.11 mSv. Image quality was assessed with a visual grading analysis and with a CDRAD contrast-detail phantom together with a computer program. The VGA showed inferior image quality for the higher kV settings, > or =96 kVwith similar results for the contrast-detail phantom. When keeping the effective dose fixed, it seems beneficial to reduce kV to get the best image quality despite the fact that the mAs is not as high as with automatic exposure. However, this cannot be done with automatic exposure, which is set for a constant Detector dose.
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dose image optimisation in Digital radiology with a direct Digital Detector an example applied to pelvic examinations
European Radiology, 2002Co-Authors: Jan Persliden, Håkan Geijer, Karl-wilhelm Beckman, Torbjörn AnderssonAbstract:In diagnostic radiology increasing attention has been focused on dose reduction while maintaining a clinically good image quality. With the use of Digital Detectors balancing dose vs image quality is done differently than in film-screen radiography, since dose and image brightness are uncoupled in Digital imaging. In this study a new direct Digital Detector (flat-panel Detector) was used in a dose-image optimisation of a simulated pelvic examination. X-ray images were taken with a direct Digital Detector (DDD), of the pelvic of a phantom using varying tube current (varying stochastic noise). The entrance surface dose was measured for each image. These images were scored by two radiologists according to EU guidelines. A dose comparison was made with an older PCR system (storage phosphor plates). With decreasing tube current the noise in the images increased and the image with the lowest dose and still acceptable image quality was identified. The results showed that the entrance surface dose using the DDD decreased from 1.4 mGy (PCR value) to 0.48 mGy (DDD standard settings). Through the optimisation the dose could be further decreased to 0.24 mGy while still maintaining an acceptable image quality. A substantial dose reduction was obtained with this new direct Digital Detector. This simple but efficient optimisation approach is easily applicable to other examinations and both DDD and storage phosphor plate Detectors.
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Optimisation of the relationship of the dose-image quality for a new direct Digital Detector.
2001Co-Authors: Jan Persliden, Håkan Geijer, Karl-wilhelm Beckman, Torbjörn AnderssonAbstract:Optimisation of the relationship of the dose-image quality for a new direct Digital Detector.
Joseph Anthony Heanue - One of the best experts on this subject based on the ideXlab platform.
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a multimode Digital Detector readout for solid state medical imaging Detectors
IEEE Journal of Solid-state Circuits, 1998Co-Authors: Colby D Boles, Bernhard E Boser, B H Hasegawa, Joseph Anthony HeanueAbstract:A multipurpose Digital Detector readout for medical imaging applications is presented. The readout is capable of measuring both current and charge, allowing a single Detector array to perform imaging functions previously accomplished with two separate machines. The circuit employs a variable rate /spl Sigma//spl Delta/ analog-to-Digital converter (ADC) to measure current over a 130-dB dynamic range in a 1 kHz band and resolve charge pulses down to 360 e/sup -/ at 100 000 events/s. Detector currents of up to 7 /spl mu/A and charge pulses as large as 25 fC can be measured. A low-noise charge sensing amplifier (CSA) is combined with Digital pulse shaping to optimize the noise performance and flexibility of the charge measurements. Fabricated in an 1.2 /spl mu/m complimentary metal-oxide-semiconductor (CMOS), the circuit occupies 1.5 mm/sup 2/ and dissipates 11 mW/channel from a 5 V supply.
Heanue - One of the best experts on this subject based on the ideXlab platform.
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A Multi-mode Digital Detector Readout For Solid-state Medical Imaging Detectors
Symposium on VLSI Circuits, 1997Co-Authors: Boles, Hasegawa, HeanueAbstract:A multipurpose Digital Detector readout for medical imaging applications is presented. The readout is capable of measuring both current and charge, allowing a single Detector array to perform imaging functions previously accomplished with two separate machines. The circuit employs a variable rate analog-to-Digital converter (ADC) to measure current over a 130- dB dynamic range in a 1 kHz band and resolve charge pulses down to 360e at 100 000 events/s. Detector currents of up to 7 A and charge pulses as large as 25 fC can be measured. A low-noise charge sensing amplifier (CSA) is combined with Digital pulse shaping to optimize the noise performance and flexibility of the charge measurements. Fabricated in an 1.2 m complimentary metal-oxide-semiconductor (CMOS), the circuit occupies 1.5 mm and dissipates 11 mW/channel from a 5 V supply.
Oliver Cossairt - One of the best experts on this subject based on the ideXlab platform.
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Subsampled phase retrieval for temporal resolution enhancement in lensless on-chip holographic video
Biomedical optics express, 2017Co-Authors: Donghun Ryu, Zihao Wang, Guoan Zheng, Roarke Horstmeyer, Oliver CossairtAbstract:On-chip holographic video is a convenient way to monitor biological samples simultaneously at high spatial resolution and over a wide field-of-view. However, due to the limited readout rate of Digital Detector arrays, one often faces a tradeoff between the per-frame pixel count and frame rate of the captured video. In this report, we propose a subsampled phase retrieval (SPR) algorithm to overcome the spatial-temporal trade-off in holographic video. Compared to traditional phase retrieval approaches, our SPR algorithm uses over an order of magnitude less pixel measurements while maintaining suitable reconstruction quality. We use an on-chip holographic video setup with pixel sub-sampling to experimentally demonstrate a factor of 5.5 increase in sensor frame rate while monitoring the in vivo movement of Peranema microorganisms.
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Subsampled Phase Retrieval for On-chip Lensless Holographic Video
arXiv: Optics, 2016Co-Authors: Donghun Ryu, Zihao Wang, Roarke Horstmeyer, Oliver CossairtAbstract:On-chip holographic video is a convenient way to monitor biological samples simultaneously at high spatial resolution and over a wide field-of-view. However, due to the limited readout rate of Digital Detector arrays, one often faces a tradeoff between the per-frame pixel count and frame rate of the captured video. In this report, we propose a subsampled phase retrieval (SPR) algorithm to overcome the spatial-temporal trade-off in holographic video. Compared to traditional phase retrieval approaches, our SPR algorithm uses over an order of magnitude less pixel measurements while maintaining suitable reconstruction quality. We use an on-chip holographic video setup with pixel sub-sampling to experimentally demonstrate a factor of 5.5 increase in sensor frame rate while monitoring the in vivo movement of Peranema microorganisms.