The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Hisatoshi Maeda - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography
Nuclear Medicine and Molecular Imaging, 2017Co-Authors: Takanaga Niimi, Mamoru Nanasato, Mitsuo Sugimoto, Hisatoshi MaedaAbstract:Purpose The differences in performance between the cadmium-zinc-telluride (CZT) camera or collimation systems and conventional Anger single-photon emission computed tomography (A-SPECT) remain insufficient from the viewpoint of the user. We evaluated the performance of the D-SPECT (Spectrum Dynamics, Israel) system to provide more information to the cardiologist or radiological technologist about its use in the clinical field. Materials and Methods This study evaluated the performance of the D-SPECT system in terms of energy Resolution, Detector sensitivity, spatial Resolution, modulation transfer function (MTF), and collimator Resolution in comparison with that of A-SPECT (Bright-View, Philips, Japan). Energy Resolution and Detector sensitivity were measured for Tc-99m, I-123, and Tl-201. The SPECT images produced by both systems were evaluated visually using the anthropomorphic torso phantom. Results The energy Resolution of D-SPECT with Tc-99m and I-123 was approximately two times higher than that of A-SPECT. The Detector sensitivity of D-SPECT was higher than that of A-SPECT (Tc-99m: 4.2 times, I-123: 2.2 times, and Tl-201: 5.9 times). The mean spatial Resolution of D-SPECT was two times higher than that of A-SPECT. The MTF of D-SPECT was superior to that of the A-SPECT system for all frequencies. The collimator Resolution of D-SPECT was lower than that of A-SPECT; however, the D-SPECT images clearly indicated better spatial Resolution than the A-SPECT images. Conclusion The energy Resolution, Detector sensitivity, spatial Resolution, and MTF of D-SPECT were superior to those of A-SPECT. Although the collimator Resolution was lower than that of A-SPECT, the D-SPECT images were clearly of better quality.
Jian Zhou - One of the best experts on this subject based on the ideXlab platform.
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Experimental assessment of Resolution improvement of a zoom-in PET
Physics in medicine and biology, 2011Co-Authors: Yang Yongfeng, Jian Zhou, Simon R. CherryAbstract:We have proposed a zoom-in positron emission tomography (PET) system that incorporates a high-Resolution Detector into an existing PET scanner to obtain high-Resolution images of a region of interest. Previously we have shown by computer simulations that the high-Resolution Detector can improve the overall system performance in terms of spatial Resolution and lesion detectability. In this study, we assessed the Resolution improvement in a real system by incorporating a high-Resolution Detector into our existing microPET II scanner. The high-Resolution Detector consists of a 14 × 28 array of 0.5 × 0.5 × 10 mm3 lutetium oxyorthosilicate scintillator elements and is placed near the center of the microPET II scanner. It is coupled to two 64-channel photomultiplier tubes (PMTs) via tapered optical fiber bundles. The PMT signals were read out by the electronics in the microPET II scanner. A 15 µCi Na-22 point source was positioned at various locations above the high-Resolution Detector. Images were reconstructed using the data measured by the microPET II scanner alone and the microPET II data combined with the high-Resolution Detector data. Profiles taken through the reconstructed point sources show substantial reduction in full-width-at-half-maximum along the direction parallel to the face of the high-Resolution Detector.
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Adaptive Imaging for Lesion Detection Using a Zoom-in PET System
IEEE transactions on medical imaging, 2010Co-Authors: Jian ZhouAbstract:Positron emission tomography (PET) has become a leading modality in molecular imaging. Demands for further improvements in spatial Resolution and sensitivity remain high with growing number of applications. In this paper we present a novel PET system design that integrates a high-Resolution depth-of-interaction (DOI) Detector into an existing PET system to obtain higher-Resolution and higher-sensitivity images in a target region around the face of the high-Resolution Detector. A unique feature of the proposed PET system is that the high-Resolution Detector can be adaptively positioned based on the detectability or quantitative accuracy of a feature of interest. This paper focuses on the signal-known-exactly, background-known-exactly (SKE-BKE) detection task. We perform theoretical analysis of lesion detectability using computer observers, and then develop methods that can efficiently calculate the optimal position of the high-Resolution Detector that maximizes the lesion detectability. We simulated incorporation of a high-Resolution DOI Detector into the microPET II scanner. Quantitative results verified that the new system has better performance than the microPET II scanner in terms of spatial Resolution and lesion detectability, and that the optimal position for lesion detection can be reliably predicted by the proposed method.
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Efficient system modeling of a high-Resolution zoom-in PET scanner
IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010Co-Authors: Jian ZhouAbstract:We have proposed a “zoom-in” PET system that integrates a higher-Resolution Detector capable of measuring depth of interaction (DOI) into an existing scanner to obtain highResolution images of a targeted region with high-sensitivity. The system acquires coincidence events between the high-Resolution Detector and low-Resolution Detectors, as well as those between the low-Resolution Detectors. Because of the irregular system geometry and the use of a DOI Detector, the system matrix of the zoom-in PET system requires far greater storage space than that of a conventional PET scanner, which also results in long computational time for image reconstruction. To address this issue, here we propose a system matrix factorization for the zoom-in PET to reduce the storage and computational cost while maintaining the accuracy in image reconstruction. The proposed factored system matrix consists of two major components: a Detector response (or sinogram blurring) matrix and a geometrical projection matrix. We present a novel method to design the geometrical component and an iterative algorithm to estimate the Detector response matrix. A 2D simulation study showed that the proposed method can reduce the storage space and reconstruction time by a factor of 5 without noticeable sacrifice in image quality.
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Theoretical analysis and simulation study of a high-Resolution zoom-in PET system
Physics in Medicine and Biology, 2009Co-Authors: Jian Zhou, Jinyi QiAbstract:We study a novel PET system that integrates a high-Resolution zoom-in Detector into an existing PET scanner to provide higher Resolution and sensitivity in a target region. In contrast to a full-ring PET insert, the proposed system is designed to focus on the target region close to the face of the high-Resolution Detector. The proposed design is easier to implement than a full-ring insert and provides flexibility for adaptive PET imaging. We developed a maximum a posteriori (MAP) image reconstruction method for the proposed system. Theoretical analysis of the Resolution and noise properties of the MAP reconstruction is performed. We show that the proposed PET system offers better performance in terms of Resolution-noise tradeoff and lesion detectability. The results are validated using computer simulations.
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IPMI - High-Resolution Adaptive PET Imaging
Information processing in medical imaging : proceedings of the ... conference, 2009Co-Authors: Jian ZhouAbstract:While the performance of small animal PET systems has been improved impressively in terms of spatial Resolution and sensitivity, demands for further improvements remain high with growing number of applications. Here we propose a novel PET system design that integrates a high-Resolution Detector into an existing PET system to obtain higher-Resolution images in a target region. The high-Resolution Detector will be adaptively positioned based on the detectability or quantitative accuracy of a feature of interest. The proposed system will be particularly effective for studying human cancers using animal models where tumors are often grown near the skin surface and therefore permit close contact with the high Resolution Detector. It will also be useful for the high-Resolution brain imaging in rodents. In this paper, we present the theoretical analysis and Monte Carlo simulation studies of the performance of the proposed system.
Stephen Rudin - One of the best experts on this subject based on the ideXlab platform.
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SU-C-209-03: Anti-Scatter Grid-Line Artifact Minimization for Removing the Grid Lines for Three Different Grids Used with a High Resolution CMOS Detector
Medical Physics, 2016Co-Authors: R Rana, Daniel R. Bednarek, Stephen RudinAbstract:Purpose: Demonstrate the effectiveness of an anti-scatter grid artifact minimization method by removing the grid-line artifacts for three different grids when used with a high Resolution CMOS Detector. Method: Three different stationary x-ray grids were used with a high Resolution CMOS x-ray Detector (Dexela 1207, 75 µm pixels, sensitivity area 11.5cm × 6.5cm) to image a simulated artery block phantom (Nuclear Associates, Stenosis/Aneurysm Artery Block 76–705) combined with a frontal head phantom used as the scattering source. The x-ray parameters were 98kVp, 200mA, and 16ms for all grids. With all the three grids, two images were acquired: the first for a scatter-less flat field including the grid and the second of the object with the grid which may still have some scatter transmission. Because scatter has a low spatial frequency distribution, it was represented by an estimated constant value as an initial approximation and subtracted from the image of the object with grid before dividing by an average frame of the grid flat-field with no scatter. The constant value was iteratively changed to minimize residual grid-line artifact. This artifact minimization process was used for all the three grids. Results: Anti-scatter grid lines artifacts were successfully eliminated in all the three final images taken with the three different grids. The image contrast and CNR were also compared before and after the correction, and also compared with those from the image of the object when no grid was used. The corrected images showed an increase in CNR of approximately 28%, 33% and 25% for the three grids, as compared to the images when no grid at all was used. Conclusion: Anti-scatter grid-artifact minimization works effectively irrespective of the specifications of the grid when it is used with a high spatial Resolution Detector. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems Corp.
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MO‐FF‐A4‐01: Effect of Focal Spot Sizes and Magnification on the Total System Performance for a High Resolution Detector System Using Generalized Linear System Metrics (GMTF, GDQE)
Medical Physics, 2010Co-Authors: Amit Jain, Daniel R. Bednarek, Stephen RudinAbstract:Purpose: The generalized linear system metrics(GMTF, GNNPS, and GDQE) provide measures of the total system performance including the effects of the image Detector, scatter from the object, focal‐spot size, and magnification. In this study, these generalized metrics were used to evaluate the effect of focal‐spot size and magnification on system performance when using a high‐Resolution image Detector.Method and Materials: The micro‐angiographic fluoroscope (MAF)(35 micron pixel and 300 micron thick CsI), a newly developed high‐Resolution Detector with very low instrumentation noise and large variable gain was used for the study. The DetectorMTF was measured using the slanted edge method and the focal spot MTF's were measured using a standard pin‐hole assembly. The scatter fraction was measured for a head‐equivalent phantom. For the comparison analysis, the GMTF, GNNPS and GDQE were determined for different magnifications corresponding to different planes within the phantom and for three different focal spots(0.3 mm, 0.5 mm and, 0.8 mm). Results: Results showed the MAF performance is affected significantly by the choice of focal‐spot size because of its very small pixel size. We found about 29, 66 and 87% decrements in MTFs at 50% of the Nyquist(i.e.,7.1 cycles/mm in object plane) for the small, medium and large focal spots, respectively, at the mid‐object plane with a magnification factor of 1.1. The corresponding decrements in DQEs were 63, 92 and 98%. Conclusion: This study demonstrates the significance of focal‐spot size and magnification on the system performance when using a high‐Resolution Detector and shows a need to choose the optimum focal spot based on the location of the object plane to be imaged. Similar studies based on the generalized linear system metrics can serve as an efficient tool to evaluate total system capabilities under different realistic conditions to enable optimal design for the specific imaging tasks. (Support:NIH‐Grant R01EB002873)
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SU-FF-I-45: Labview Graphical User Interface for Micro Angio-Fluoroscopic High Resolution Detector
Medical Physics, 2006Co-Authors: C Keleshis, Ciprian N. Ionita, Stephen RudinAbstract:Purpose: A graphical user interface based on LabView software was developed to control a Micro Angio‐Fluoroscopic Detector (MAF) for real‐time acquisition, display and rapid frame transfer of high Resolution images of a region‐of‐interest. Method and Materials: A MAF Detector was built by our group using a CsI(Tl) phosphor, fiber‐optic taper and Light Amplifier optically coupled to a progressive scan charged coupled device(CCD)camera which provides real‐time 12 bit, 1k × 1k images. During image acquisition, the MAF Detector is inserted in the x‐ray beam of an angiographic unit, between the x‐ray image intensifier and the patient. Images can be captured in continuous or triggered mode and the camera can be programmed by a computer using the serial communication. A graphical user interface was developed to control the camera modes such as gain and pixel binning as well as to acquire, store, display, and process the images.Results: The program, written in LabView, has the following capabilities: camera initialization, synchronized image acquisition with the x‐ray pulses, flat field correction, window and level adjustment, brightness and contrast control, and looped play‐back of the acquired images. Acquisition starts when the first triggering pulse is read by the interface. The acquired sequence of images is automatically displayed in a loop after completion of acquisition and the images can be stored or deleted at the user's discretion. Frame rates can be up to 30fps in 2×2 binning mode and 25fps unbinned. Conclusion: The user friendly implementation of the interface along with the high frame rate acquisition and display for this unique high Resolution Detector may provide angiographers a new capability for visualizing details of small endovascular devices such as stents and hence enable more accurate image guided localization. (Support: NIH Grants R01NS43924, R01EB002873).
Takanaga Niimi - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography
Nuclear Medicine and Molecular Imaging, 2017Co-Authors: Takanaga Niimi, Mamoru Nanasato, Mitsuo Sugimoto, Hisatoshi MaedaAbstract:Purpose The differences in performance between the cadmium-zinc-telluride (CZT) camera or collimation systems and conventional Anger single-photon emission computed tomography (A-SPECT) remain insufficient from the viewpoint of the user. We evaluated the performance of the D-SPECT (Spectrum Dynamics, Israel) system to provide more information to the cardiologist or radiological technologist about its use in the clinical field. Materials and Methods This study evaluated the performance of the D-SPECT system in terms of energy Resolution, Detector sensitivity, spatial Resolution, modulation transfer function (MTF), and collimator Resolution in comparison with that of A-SPECT (Bright-View, Philips, Japan). Energy Resolution and Detector sensitivity were measured for Tc-99m, I-123, and Tl-201. The SPECT images produced by both systems were evaluated visually using the anthropomorphic torso phantom. Results The energy Resolution of D-SPECT with Tc-99m and I-123 was approximately two times higher than that of A-SPECT. The Detector sensitivity of D-SPECT was higher than that of A-SPECT (Tc-99m: 4.2 times, I-123: 2.2 times, and Tl-201: 5.9 times). The mean spatial Resolution of D-SPECT was two times higher than that of A-SPECT. The MTF of D-SPECT was superior to that of the A-SPECT system for all frequencies. The collimator Resolution of D-SPECT was lower than that of A-SPECT; however, the D-SPECT images clearly indicated better spatial Resolution than the A-SPECT images. Conclusion The energy Resolution, Detector sensitivity, spatial Resolution, and MTF of D-SPECT were superior to those of A-SPECT. Although the collimator Resolution was lower than that of A-SPECT, the D-SPECT images were clearly of better quality.
Mitsuo Sugimoto - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography
Nuclear Medicine and Molecular Imaging, 2017Co-Authors: Takanaga Niimi, Mamoru Nanasato, Mitsuo Sugimoto, Hisatoshi MaedaAbstract:Purpose The differences in performance between the cadmium-zinc-telluride (CZT) camera or collimation systems and conventional Anger single-photon emission computed tomography (A-SPECT) remain insufficient from the viewpoint of the user. We evaluated the performance of the D-SPECT (Spectrum Dynamics, Israel) system to provide more information to the cardiologist or radiological technologist about its use in the clinical field. Materials and Methods This study evaluated the performance of the D-SPECT system in terms of energy Resolution, Detector sensitivity, spatial Resolution, modulation transfer function (MTF), and collimator Resolution in comparison with that of A-SPECT (Bright-View, Philips, Japan). Energy Resolution and Detector sensitivity were measured for Tc-99m, I-123, and Tl-201. The SPECT images produced by both systems were evaluated visually using the anthropomorphic torso phantom. Results The energy Resolution of D-SPECT with Tc-99m and I-123 was approximately two times higher than that of A-SPECT. The Detector sensitivity of D-SPECT was higher than that of A-SPECT (Tc-99m: 4.2 times, I-123: 2.2 times, and Tl-201: 5.9 times). The mean spatial Resolution of D-SPECT was two times higher than that of A-SPECT. The MTF of D-SPECT was superior to that of the A-SPECT system for all frequencies. The collimator Resolution of D-SPECT was lower than that of A-SPECT; however, the D-SPECT images clearly indicated better spatial Resolution than the A-SPECT images. Conclusion The energy Resolution, Detector sensitivity, spatial Resolution, and MTF of D-SPECT were superior to those of A-SPECT. Although the collimator Resolution was lower than that of A-SPECT, the D-SPECT images were clearly of better quality.