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IEEE International Workshop on Genomic Signal Processing and Statistics (GENSIPS)

作者： Linlin Cong Ying Chen Weihua Zhou Biomedical Engineering Graduate Program Southem Illinois University Carbondale IL USA Department of Electrical and Computer Engineering Southem Illinois University Carbondale IL USA

Digital breast tomosynthesis is a novel breast cancer detection technique by allowing the reconstruction of arbitrary planes in the breast from a set of limited-angle projection images acquired at different view angles with a particular tube geometry setup. In this paper, filtered backprojection (FBP) was optimized as the reconstruction method with a parallel imaging breast tomosynthesis system. The slice thickness filter (profile filter) with task-adapted parameters was applied to computer simulated data, in order to investigate the main effects of this kind of filter regarding spatial resolution and artifacts in the reconstructed results.

关键词： Image reconstruction Breast Filtering algorithms Detectors X-ray imaging Reconstruction algorithms

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The effect of intramedullary stem curvature on the torsional stability of cemented joint replacement systems

The effect of intramedullary stem curvature on the torsional...

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ASME 2011 Summer Bioengineering Conference, SBC 2011

作者： Hosein, Yara K. Clynick, Meghan P. Takaki, Sarah E. McLachlin, Stewart D. Dunning, Cynthia E. Jack McBain Biomechanical Testing Laboratory Biomedical Engineering Graduate Program University of Western Ontario London ON N6A 5B9 Canada Jack McBain Biomechanical Testing Laboratory Department of Materials and Mechanical Engineering University of Western Ontario London ON N6A 5B9 Canada

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TU-A-218-01: Estimation of the 2-D Presampled MTF of a Digital Flat Panel Detector Using an Edge Test Device

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Medical Physics 2012年第6PART23期39卷 3894-3894页

作者： J Wells J Dobbins Carl E. Ravin Advanced Imaging Laboratories Duke University Medical Center Durham NC Medical Physics Graduate Program Duke University Medical Center Durham NC Department of Radiology Duke University Medical Center Durham NC Department of Biomedical Engineering Duke University Durham NC

Purpose: In this work, we report on the novel application of an opaque edge test device for practical estimation of the 2-D modulation transfer function (MTF) of a digital flat panel (DFP) detector. Methods: We estimated the 2- D MTF of a prototype GE Revolution XQ/i DFP detector (GE Healthcare, Waukesha, WI) using an opaque edge test device. The original work by Samei et al. [Med. Phys. 25, 102–113 (1998)] served as the basis of our methodology to which we also contributed further theoretical analysis regarding sub-pixel precision of 1 -D MTF measurements at arbitrary angle. The edge was imaged five times at each of ten angles relative to the sampling lattice: 1.33, 7.59, 20.22, 30.29, 37.90, 48.07, 58.85, 69.78, 78.13, and 88.02 degrees. The 1-D MTF was computed from edge data at each angle using Fourier analysis. The 2-D MTF was estimated through a simple surface fit and linear interpolation scheme based on Delaunay triangulation of the collection of 1-D MTF data. Results: All angles yielded nearly identical 1-D MTFs with relative standard deviations of 0.39%, 1.3%, 4.2%, and 5.6% at 1, 2, 3, and 4 cycles/mm, respectively. These measurements exhibited no discernible patterns with respect to acquisition angle indicating that the 2-D MTF has approximate circular symmetry at frequencies below 4 cycles/mm. Although this assertion agrees with the conclusions of other authors, blur due to the finite rectangular pixel aperture may merit further investigation at the highest spatial frequencies where the MTF may not behave in a circularly symmetric manner. Conclusions: We present for the first time the practical estimation of the 2-D MTF of a DFP detector using an edge test device. The general availability, acceptance, and ease of implementation of edge-based MTF assessments make this a valuable technique for 2-D MTF measurement in academic, industrial, and clinical settings.

关键词： Modulation transfer functions Germanium Fourier analysis Interpolation Medical imaging Lattice theory

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A Compton scattering suppression based image reconstruction method for Digital Breast Tomosynthesis

A Compton scattering suppression based image reconstruction ...

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IEEE International Workshop on Genomic Signal Processing and Statistics (GENSIPS)

作者： Shiyu Xu Ying Chen Department of Electrical and Computer Engineering Southem Illinois University Carbondale IL USA Department of Electrical and Computer Engineering and Biomedical Engineering Graduate Program Southem Illinois University Carbondale IL USA

In this paper, we present a novel statistical reconstruction method based on Compton noise suppression for Digital Breast Tomosynthesis. The physical modeling for X-ray's interaction with tissues was investigated. A Compton noise based statistical model with a conjugate prior was introduced. Results from our proposed method, Backprojection (BP) method, Simultaneous Algebraic Reconstruction Technique (SART) and Maximum Likelihood with Convex Algorithm (MLCA) were compared based on image quality analysis. Compared with other algorithms, our proposed method shows comparable performance. It also produces even better results in the Contrast to Noise Ratio (CNR) evaluation.

关键词： Image reconstruction Noise Attenuation Scattering Breast Reconstruction algorithms Image quality

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Physiological Variables and Subjective Symptoms by 60 Hz Magnetic Field in EHS and Non-EHS Persons

Physiological Variables and Subjective Symptoms by 60 Hz Mag...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： Ki Chang Nam Jae Lim Choi Min Kyung Kwon Kyung Hwan Jang Deok Won Kim Dept. of Medical Engineering Yonsei University College of Medicine Graduate Program in Biomedical Engineering Yonsei University Brain Korea 21 Project for Medical Science Yonsei University

ISBN: (纸本)9781424441211

Electromagnetic hypersensitivity (EHS) is a set of claims of adverse medical symptoms self attributed by exposure to electromagnetic field. In this study, we simultaneously investigated both physiological changes (heart rate, respiration rate, and heart rate variability) and subjective symptoms to determine the origin of EHS. Two volunteer groups (15 self-reported EHS and 16 non-EHS participants) were tested under both sham and real exposure to 12.5 μT magnetic fields at 60 Hz that lasted a half an hour. The magnetic field exposure did not have any effect on physiological variables or subjective symptoms in either group. We conclude that the subjective symptoms did not result from exposure to 12.5 μT magnetic field at 60 Hz.

关键词： magnetic field Hz Symptoms Electromagnetic fields heart rate variability Placebos Persons exposure to magnetic field

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Effects of RF Fields Emitted from Smart Phones on Cardio-Respiratory Parameters: A Preliminary Provocation Study

Effects of RF Fields Emitted from Smart Phones on Cardio-Res...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： Min Kyung Kwon Ki Chang Nam Da Som Lee Kyung Hwan Jang Deok Won Kim Brain Korea 21 Project for Medical Science Yonsei University Dept. of Medical Engineering Yonsei University College of Medicine Graduate Program in Biomedical Engineering Yonsei University

ISBN: (纸本)9781424441211

This paper describes an experimental setup for evaluating the physiological effects of radiofrequency (RF) emitted from a Wideband Code Division Multiple Access (WCDMA) module with a 24 dBm at 1950 MHz for specific absorption rate (SAR_(1g)) of 1.57 W/kg. This provocation study was executed in a double-blind study of two volunteer groups of 10 self-reported electromagnetic hypersensitivity (EHS) and 10 non-EHS subjects under both sham and real exposures in a randomly assigned and counter-balanced order. In the preliminary results, WCDMA RF exposure of 30 min did not have any effects on physiological changes in either group.

关键词： Smartphone WCDMA radiofrequency Double-Blind Method anti-balance Placebos code division Specific absorption rate

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Comparison of dual-window scatter correction and effective attenuation coefficients for quantification in dedicated breast SPECT

Comparison of dual-window scatter correction and effective a...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Steve Mann Kristy Perez Martin Tornai Medical Physics Graduate Program Duke University Durham NC USA Department of Radiology Duke University Durham NC USA Department of Radiology Department of Biomedical Engineering and Medical Physics Graduate Program Duke University Durham NC USA

Correction for scattered and attenuated photons is necessary for accurate quantification in dedicated breast SPECT. An implemented dual energy window (DEW) scatter correction method along with attenuation correction has been shown to be accurate to within 10% of true values; however, the DEW method requires multiple processing steps, and thus more time, than an effective attenuation coefficient (EAC) method. This study aims to determine an EAC for quantification accuracy comparable to the DEW method. Our dedicated, high performance CZT-based breast SPECT system is capable of novel 3D, non-traditional trajectories. A breast phantom containing lesions ranging from 0.1 to 1.6mL was filled with Tc-99m to 8:1 and 4:1 lesion-to-background activity concentrations. Multiple acquisitions were collected using vertical axis of rotation (VAOR) and projected sine wave (PROJSINE) orbits and an 8% energy window. The PROJSINE trajectory incompletely samples the volume, but offers potential clinical benefits by contouring the breast and acquiring chest wall projections. Images were reconstructed with OSEM to 20 iterations using both uniform EAC masks with values of 0.12 to 0.165cm -1 and the DEW method with measured 0.16 scatter coefficient and the NIST attenuation value of 0.1545cm -1 for water at 140keV. ROIs were seeded and automatically drawn within each lesion, and measured values were compared to known truth. Results indicate that the DEW method is superior for VAOR trajectories and a single EAC value may not adequately compensate non-uniformly shaped objects that have a spatially varying scatter distribution. However, for PROJSINE trajectories, an EAC of approximately 0.13cm -1 yields comparable quantification accuracy for background and large lesions without the need for additional image processing, indicating this may have clinical utility in image quantification.

关键词： Imaging Trajectory

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Simultaneous identification for synergistic transcription factors and their transcription factor binding sites

Simultaneous identification for synergistic transcription fa...

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5th International Conference on Complex, Intelligent and Software Intensive Systems, CISIS 2011

作者： Tsai, Zing Tsung-Yeh Huang, Grace Tzu-Wei Tsai, Huai-Kuang Institute of Information Science Academia Sinica Taipei 115 Taiwan Bioinformatics Program Taiwan International Graduate Program Taiwan Institute of Biomedical Informatics National Yang-Ming University Taiwan Joint CMU-Pitt PhD Program in Computational Biology University of Pittsburgh Carnegie Mellon University Pittsburgh PA United States Research Center for Information Technology Innovation Taipei 115 Taiwan Computer Science and Engineering National Taiwan Ocean University Keelung 202 Taiwan

ISBN: (纸本)9780769543734

Identifying transcription factor binding sites (TFBSs) is crucial for understanding the mechanism of transcriptional regulation. It is known that transcription factors (TFs) often cooperate to regulate genes. While traditional approaches can be used to discover binding motifs of a group of co-regulated genes, they often fail to accurately assign motifs to the corresponding TFs. Here, we consider two TFs together to infer their TFBSs and their synergistic relationship simultaneously. The basic idea is that if two TFs interact, their TFBSs, if distinct, would be conserved across species and coincided in the promoter regions of the genes they co-regulated. Applying our method to Saccharomyces cerevisiae chromatin immunoprecipitation data, we predicted 110 TF pairs with statistically significant motif assignments. A majority of these TF pairs have literature support to be synergistic, and the designated motifs to TFs match well with their known consensus. We further examined the synergism of predicted TF pairs in seven experimental conditions using ANOVA, and identified significant interactions. © 2011 IEEE.

关键词： Yeast

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Fabrication of uniform QPM device using negative multiple pulse poling method

Fabrication of uniform QPM device using negative multiple pu...

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2011 International Quantum Electronics Conference, IQEC 2011 and Conference on Lasers and Electro-Optics, CLEO Pacific Rim 2011

作者： Choi, Ju Won Kang, Heejong Ko, Do-Kyeong Ro, Jung Hoon Yu, Nan Ei Graduate Program of Photonics and Applied Physics Gwangju Institute of Science and Technology Gwangju 500-712 Korea Republic of Advanced Photonics Research Institute Gwangju Institute of Science and Technology Gwangju 500-712 Korea Republic of Department of Biomedical Engineering School of Medicine Pusan National University Busan 602-739 Korea Republic of

We introduced a novel negative multiple pulse poling (NMP) method for uniform device fabrication of quasi-phase matching using an in-situ visualization system. Diffraction pattern analysis showed the duty ratio of 0.4... 详细信息

ISBN: (纸本)9780977565771

关键词： Fabrication

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MO-G-BRA-03: Semi-Automatic Segmentation of the Prostate Midgland in Magnetic Resonance Images Using Shape and Local Appearance Similarity Analysis

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Medical Physics 2012年第6PART22期39卷 3881-3881页

作者： M Shahedi A Fenster C Romagnoli A D Ward Imaging Research Laboratories Robarts Research Institute Western University London ON Canada Baines Imaging Research Laboratory London Health Sciences Centre London ON Canada Graduate Program in Biomedical Engineering Western University London ON Canada Department of Medical Biophysics Western University London ON Canada Department of Medical Imaging Western University London ON Canada

Purpose : To design, develop and test a semi-automatic segmentation method for the prostate midgland on T2W magnetic resonance (MR) images acquired using an endorectal (ER) coil, based on inter-subject prostate shape and local boundary appearance *** and Materials: We used T2W prostate MR images of 33 subjects acquired using an ER coil. From each image, we extracted the closest mid-gland axial slice to the verumontanum. We partitioned the images into training and test sets using leave-one-out cross-validation. We used the training images to define a point distribution model (PDM) describing shape variability as well as 36 circular ‘mean intensity patches' characterizing the inter-subject local appearance at anatomically-defined boundary locations. We chose a patch radius of 17mm based on our assessment of segmentation error, using the mean absolute boundary distance (MAD), on a subset of 13 images during a systematic radius search from 5mm to 25mm. For each test image, we defined 36 homologous rays emanating from the centre of the prostate. We used a radial-based-search strategy to translate each mean intensity patch along its corresponding ray and computed the normalized cross-correlation (NCC) between the mean patch and the underlying patch in the test image at each point. We chose the point with the highest NCC along each ray. We then used the PDM to regularize the selected points. To compare the algorithm's segmentation to manual delineations performed by one operator, we calculated the MAD and Dice similarity coefficient (DSC). Results : We measured a MAD of 1.6 +/− 1.0mm, and a DSC of 89 +/− 6% between the semi-automatically segmented contours and the manually-delineated reference standard. Conclusions : NCC of local prostate boundary regions with a learned mean boundary appearance may be suitable for boundary localization and subsequent refinement using a PDM on T2W MR images acquired using an ER coil.

关键词： Medical imaging Medical magnetic resonance imaging Medical image segmentation Materials analysis Magnetic resonance Image analysis Magnetic materials

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