1. Articles from Chao Zhou

    1-24 of 47 1 2 »
    1. Full-range space-division multiplexing optical coherence tomography angiography

      Full-range space-division multiplexing optical coherence tomography angiography

      Abstract In this study, we demonstrated a full-range space-division multiplexing optical coherence tomography (FR-SDM-OCT) system. Utilizing the galvanometer-based phase modulation full-range technique, the total imaging range of FR-SDM-OCT can be extended to >20 mm in tissue, with a digitizer sampling rate of 500 MS/s and a laser sweeping rate of 100 kHz. Complex conjugate terms were suppressed in FR-SDM-OCT images with a measured rejection ratio of up to ∼46 dB at ∼1.4 mm depth and ∼30 dB at ∼19.4 mm depth. The feasibility of FR-SDM-OCT was validated by imaging Scotch tapes and human fingernails. Furthermore, we demonstrated ...

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    2. Post-doctoral Associate Positions in Biophotonics / Biomedical Optical Imaging at Washington University in St. Louis

      Post-doctoral Associate Positions in Biophotonics / Biomedical Optical Imaging at Washington University in St. Louis

      Position description: We are looking for highly motivated individuals to develop advanced optical imaging techniques for novel biomedical applications in vitro and/or in vivo . Successful candidates will have opportunities to collaborate with top academic and industry partners . Compensation is commensurate with experience. Qualifications: Ph.D. in Biomedical Engineering / Bioengineering, Electrical Engineering, Physics, Applied Physics or related fields. Clinical experience with ophthalmic imaging, and hands-on hardware and programming experience with optical coherence tomography (OCT), including spectral-domain and swept-source OCT, is preferred. Good publication record and communication skills. Research areas: The candidate is expected to work on one of the following ...

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    3. Longitudinal Morphological and Physiological Monitoring of Three-dimensional Tumor Spheroids Using Optical Coherence Tomography

      Longitudinal Morphological and Physiological Monitoring of Three-dimensional Tumor Spheroids Using Optical Coherence Tomography

      Optical coherence tomography (OCT), a three-dimensional imaging technology, was used to monitor and characterize the growth kinetics of multicellular tumor spheroids. Precise volumetric quantification of tumor spheroids using a voxel counting approach, and label-free dead tissue detection in the spheroids based on intrinsic optical attenuation contrast, were demonstrated.

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    4. Computer-Aided Diagnosis of Label-Free 3-D Optical Coherence Microscopy Images of Human Cervical Tissue

      Computer-Aided Diagnosis of Label-Free 3-D Optical Coherence Microscopy Images of Human Cervical Tissue

      : Ultrahigh-resolution optical coherence microscopy (OCM) has recently demonstrated its potential for accurate diagnosis of human cervical diseases. One major challenge for clinical adoption, however, is the steep learning curve clinicians need to overcome to interpret OCM images. Developing an intelligent technique for computer-aided diagnosis (CADx) to accurately interpret OCM images will facilitate clinical adoption of the technology and improve patient care. Methods: 497 high-resolution 3-D OCM volumes (600 cross-sectional images each) were collected from 159 ex vivo specimens of 92 female patients. OCM image features were extracted using a convolutional neural network (CNN) model, concatenated with patient information (e.g ...

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    5. Integrating optical coherence tomography with gravimetric and video analysis (OCT-Gravimetry-Video method) for studying the drying process of polystyrene latex system

      Integrating optical coherence tomography with gravimetric and video analysis (OCT-Gravimetry-Video method) for studying the drying process of polystyrene latex system

      Latex, an aqueous dispersion of sub-micron polymer particles, is widely used as polymer binder in waterborne coatings and adhesives. Drying of a latex is inhomogeneous, during which the spatial distribution of particles is non-uniform and changes with time, usually resulting in a compromise of the integrity of a dried film. To study drying inhomogeneity of latex, we developed a system integrating optical coherence tomography (OCT) with gravimetric and video analysis (OCT-Gravimetry-Video method) to non-destructively monitor the drying process of non-film-forming latexes consisting of hard polystyrene spheres over time. OCT structural and speckle images of the latex’s internal structure show ...

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    6. Feature Of The Week 10/15/2017: Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids

      Feature Of The Week 10/15/2017: Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids

      Three-dimensional (3D) tumor spheroid models have gained increased recognition as important tools in cancer research and anti-cancer drug development. However, currently available imaging approaches employed in high-throughput screening drug discovery platforms e.g. bright field, phase contrast, and fluorescence microscopies, are unable to resolve 3D structures deep inside (>50 μm) tumor spheroids. In this study, we established a label-free, non-invasive optical coherence tomography (OCT) imaging platform to characterize 3D morphological and physiological information of multicellular tumor spheroids (MCTS) growing from ~250 μm up to ~600 μm in height over 21 days. In particular, tumor spheroids of two cell lines glioblastoma ...

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    7. Wide-field high-speed space-division multiplexing optical coherence tomography using an integrated photonic device

      Wide-field high-speed space-division multiplexing optical coherence tomography using an integrated photonic device

      Space-division multiplexing optical coherence tomography (SDM-OCT) is a recently developed parallel OCT imaging method in order to achieve multi-fold speed improvement. However, the assembly of fiber optics components used in the first prototype system was labor-intensive and susceptible to errors. Here, we demonstrate a high-speed SDM-OCT system using an integrated photonic chip that can be reliably manufactured with high precisions and low per-unit cost. A three-layer cascade of 1 × 2 splitters was integrated in the photonic chip to split the incident light into 8 parallel imaging channels with ~3.7 mm optical delay in air between each channel. High-speed imaging ...

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    8. Integrated Local Binary Pattern Texture Features for Classification of Breast Tissue Imaged by Optical Coherence Microscopy

      Integrated Local Binary Pattern Texture Features for Classification of Breast Tissue Imaged by Optical Coherence Microscopy

      This paper proposes a texture analysis technique that can effectively classify different types of human breast tissue imaged by Optical Coherence Microscopy (OCM). OCM is an emerging imaging modality for rapid tissue screening and has the potential to provide high resolution microscopic images that approach those of histology. OCM images, acquired without tissue staining, however, pose unique challenges to image analysis and pattern classification. We examined multiple types of texture features and found Local Binary Pattern (LBP) features to perform better in classifying tissues imaged by OCM. In order to improve classification accuracy, we propose novel variants of LBP features ...

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    9. Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids

      Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids

      hree-dimensional (3D) tumor spheroid models have gained increased recognition as important tools in cancer research and anti-cancer drug development. However, currently available imaging approaches employed in high-throughput screening drug discovery platforms e.g. bright field, phase contrast, and fluorescence microscopies, are unable to resolve 3D structures deep inside (>50 μm) tumor spheroids. In this study, we established a label-free, non-invasive optical coherence tomography (OCT) imaging platform to characterize 3D morphological and physiological information of multicellular tumor spheroids (MCTS) growing from ~250 μm up to ~600 μm in height over 21 days. In particular, tumor spheroids of two cell lines glioblastoma ...

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    10. Optical Coherence Tomography for Brain Imaging and Developmental Biology

      Optical Coherence Tomography for Brain Imaging and Developmental Biology

      Optical coherence tomography (OCT) is a promising research tool for brain imaging and developmental biology. Serving as a three-dimensional optical biopsy technique, OCT provides volumetric reconstruction of brain tissues and embryonic structures with micrometer resolution and video rate imaging speed. Functional OCT enables label-free monitoring of hemodynamic and metabolic changes in the brain in vitro and in vivo in animal models. Due to its noninvasiveness nature, OCT enables longitudinal imaging of developing specimens in vivo without potential damage from surgical operation, tissue fixation and processing, and staining with exogenous contrast agents. In this paper, various OCT applications in brain imaging ...

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    11. Label-Free Imaging of Eosinophilic Esophagitis Mouse Models Using Optical Coherence Tomography

      Label-Free Imaging of Eosinophilic Esophagitis Mouse Models Using Optical Coherence Tomography

      Eosinophilic esophagitis (EoE) is an immune-mediated disorder characterized by esophageal inflammation and related structural changes causing symptoms such as feeding difficulties and food impaction. The pathophysiological mechanisms underlying EoE remain poorly understood. Preclinical studies using mouse models have been critical in comprehending human disease mechanisms and associated pathways. In this chapter, we describe an experimental method using a noninvasive label-free optical imaging technique, optical coherence tomography, to characterize the pathophysiological changes in the esophagus of mice with EoE-like disease ex vivo.

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    12. Post-doctoral Associate Position in Biophotonics/Biomedical Optical Imaging at Lehigh University

      Post-doctoral Associate Position in Biophotonics/Biomedical Optical Imaging at Lehigh University

      Position description: A full-time Postdoctoral Associate position in Biophotonics / Biomedical Optical Imaging is available at Lehigh University starting ASAP . The primary purpose of this position will be for a highly motivated individual to develop advanced optical imaging techniques for novel biomedical applications in vitro and/or in vivo . Compensation is commensurate with experience. Qualifications: Ph.D. in Electrical Engineering, Physics, Applied Physics, Biomedical Engineering / Bioengineering or related fields. Hands-on experience with optical coherence tomography (OCT), especially phase-sensitive Fourier-domain OCT, is preferred. Good publication record and communication skills. Strong programming skills (Matlab, Labview, C++ and GPU programming) are pluses. Research areas ...

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    13. Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University

      Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University

      Position description: A full-time Postdoctoral Associate position in Biophotonics / Biomedical Optical Imaging is available at Lehigh University starting ASAP . The primary purpose of this position will be for a highly motivated individual to develop advanced optical imaging techniques for novel biomedical applications in vitro and/or in vivo . Compensation is commensurate with experience. Qualifications: Ph.D. in Electrical Engineering, Physics, Applied Physics, Biomedical Engineering / Bioengineering or related fields. Hands-on experience with optical coherence tomography (OCT), especially phase-sensitive Fourier-domain OCT, is preferred. Good publication record and communication skills. Strong programming skills (Matlab, Labview, C++ and GPU programming) are pluses. Research areas ...

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    14. Optogenetic pacing in Drosophila melanogaster

      Optogenetic pacing in Drosophila melanogaster

      Electrical stimulation is currently the gold standard for cardiac pacing. However, it is invasive and nonspecific for cardiac tissues. We recently developed a noninvasive cardiac pacing technique using optogenetic tools, which are widely used in neuroscience. Optogenetic pacing of the heart provides high spatial and temporal precisions, is specific for cardiac tissues, avoids artifacts associated with electrical stimulation, and therefore promises to be a powerful tool in basic cardiac research. We demonstrated optogenetic control of heart rhythm in a well-established model organism, Drosophila melanogaster . We developed transgenic flies expressing a light-gated cation channel, channelrhodopsin-2 (ChR2), specifically in their hearts and ...

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    15. A Circadian Clock Gene, Cry, Affects Heart Morphogenesis and Function in Drosophila as Revealed by Optical Coherence Microscopy

      A Circadian Clock Gene, Cry, Affects Heart Morphogenesis and Function in Drosophila as Revealed by Optical Coherence Microscopy

      Circadian rhythms are endogenous, entrainable oscillations of physical, mental and behavioural processes in response to local environmental cues such as daylight, which are present in the living beings, including humans. Circadian rhythms have been related to cardiovascular function and pathology. However, the role that circadian clock genes play in heart development and function in a whole animal in vivo are poorly understood. The Drosophila cryptochrome (dCry) is a circadian clock gene that encodes a major component of the circadian clock negative feedback loop. Compared to the embryonic stage, the relative expression levels of dCry showed a significant increase (>100-fold) in ...

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    16. Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University

      Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University

      Position description: A full-time Postdoctoral Associate position in Biophotonics / Biomedical Optical Imaging is available at Lehigh University starting ASAP . The primary purpose of this position will be for a highly motivated individual to develop advanced optical imaging techniques for novel biomedical applications in vitro and/or in vivo . Compensation is commensurate with experience. Qualifications: Ph.D. in Electrical Engineering, Physics, Applied Physics, Biomedical Engineering / Bioengineering or related fields. Hands-on experience with optical coherence tomography (OCT), especial swept-source OCT, is preferred. Good publication record and communication skills. Strong programming skills (Matlab, Labview, C++ and GPU programming) are pluses. Research areas: The ...

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    17. Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University

      Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University

      Position description: A full-time Postdoctoral Associate position in Biophotonics / Biomedical Optical Imaging is available at Lehigh University starting ASAP . The primary purpose of this position will be for a highly motivated individual to develop advanced optical imaging techniques for novel biomedical applications in vitro and/or in vivo . Compensation is commensurate with experience. Qualifications: Ph.D. in Electrical Engineering, Physics, Applied Physics, Biomedical Engineering / Bioengineering or related fields. Hands-on experience with optical coherence tomography (OCT), especial swept-source OCT, is preferred. Good publication record and communication skills. Strong programming skills (Matlab, Labview, C++ and GPU programming) are pluses. Research areas: The ...

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    18. System And Method For Parallel Imaging Optical Coherence Tomography

      System And Method For Parallel Imaging Optical Coherence Tomography

      A parallel imaging optical coherence tomography system. In one embodiment, the system includes a light source, a movable scan unit, and an interferometer comprising a reference arm and a sample arm. The scan unit includes a plurality of apertures illuminated by incident light from the light source. The scan unit produces a plurality of light beams transmitted to the interferometer. The light beams are each split producing a plurality of reference and sampling beams. The sampling beams are scanned onto a sample and return reflected sampling light signals through the sample arm which are combined with reflected, reference light signals ...

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    19. SPACE-DIVISION Multiplexing Optical Coherence Tomography Apparatus

      SPACE-DIVISION Multiplexing Optical Coherence Tomography Apparatus

      A space-division multiplexing optical coherence tomography apparatus arid system is provided, in one embodiment, the system includes a light source, a reference arm. and a sample arm. The sample arm splits the sampling light into a plurality of sampling beams which may be scanned simultaneously onto a surface of a sample. An optical delay may be introduced into the sampling beams before scanning. A plurality of reflected light signals returned from the sample is collected. In one arrangement, the signals may be combined to produce a single reflected light signal The reflected light sigtial(s) and a reference signal are ...

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    20. Characterization of eosinophilic esophagitis murine models using optical coherence tomography

      Characterization of eosinophilic esophagitis murine models using optical coherence tomography

      Pre-clinical studies using murine models are critical for understanding the pathophysiological mechanisms underlying immune-mediated disorders such as Eosinophilic esophagitis (EoE). In this study, an optical coherence tomography (OCT) system capable of providing three-dimensional images with axial and transverse resolutions of 5 µm and 10 µm, respectively, was utilized to obtain esophageal images from a murine model of EoE-like disease ex vivo . Structural changes in the esophagus of wild-type ( Tslpr +/+ ) and mutant ( Tslpr −/− ) mice with EoE-like disease were quantitatively evaluated and food impaction sites in the esophagus of diseased mice were monitored using OCT. Here, the capability of OCT as a ...

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    21. Label-free evaluation of angiogenic sprouting in microengineered devices using ultrahigh-resolution optical coherence microscopy

      Label-free evaluation of angiogenic sprouting in microengineered devices using ultrahigh-resolution optical coherence microscopy

      Understanding the mechanism of angiogenesis could help to decipher wound healing and embryonic development and to develop better treatment for diseases such as cancer. Microengineered devices were developed to reveal the mechanisms of angiogenesis, but monitoring the angiogenic process nondestructively in these devices is a challenge. In this study, we utilized a label-free imaging technique, ultrahigh-resolution optical coherence microscopy (OCM), to evaluate angiogenic sprouting in a microengineered device. The OCM system was capable of providing ∼ 1.5 - μ m axial resolution and ∼ 2.3 - μ m transverse resolution. Three-dimensional (3-D) distribution of the sprouting vessels in the microengineered device was imaged over ...

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    22. Feature Of The Week 9/22/13: Lehigh University Researchers Investigate Space-Division Multiplexing for High-Speed Optical Coherence Tomography

      Feature Of The Week 9/22/13: Lehigh University Researchers Investigate Space-Division Multiplexing for High-Speed Optical Coherence Tomography

      High speed, high resolution and high sensitivity are desirable for optical coherence tomography (OCT). Here, we demonstrate a space-division multiplexing (SDM) technology that translates long coherence length of a commercially available wavelength tunable laser into high OCT imaging speed. We achieved an effective 800,000 A-scans/s imaging speed using a commercially available 100,000 Hz tunable vertical cavity surface-emitting laser (VCSEL) from Thorlabs Inc. A sensitivity of 94.6 dB and a roll-off of < 2 dB over ~30 mm imaging depth were measured in the prototype SDM-OCT system. An axial resolution of ~11 m in air (or ~8.3 ...

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    23. Space-division multiplexing optical coherence tomography

      Space-division multiplexing optical coherence tomography

      High speed, high resolution and high sensitivity are desirable for optical coherence tomography (OCT). Here, we demonstrate a space-division multiplexing (SDM) technology that translates long coherence length of a commercially available wavelength tunable laser into high OCT imaging speed. We achieved an effective 800,000 A-scans/s imaging speed using a 100,000 Hz tunable vertical cavity surface-emitting laser (VCSEL). A sensitivity of 94.6 dB and a roll-off of < 2 dB over ~30 mm imaging depth were measured from a single channel in the prototype SDM-OCT system. An axial resolution of ~11 μm in air (or ~8.3 μm ...

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    24. Ultrahigh speed endoscopic optical coherence tomography using micromotor imaging catheter and VCSEL technology

      Ultrahigh speed endoscopic optical coherence tomography using micromotor imaging catheter and VCSEL technology

      We developed a micromotor based miniature catheter with an outer diameter of 3.2 mm for ultrahigh speed endoscopic swept source optical coherence tomography (OCT) using a vertical cavity surface-emitting laser (VCSEL) at a 1 MHz axial scan rate. The micromotor can rotate a micro-prism at several hundred frames per second with less than 5 V drive voltage to provide fast and stable scanning, which is not sensitive to the bending of the catheter. The side-viewing probe can be pulled back to acquire a three-dimensional (3D) data set covering a large area on the specimen. The VCSEL provides a high ...

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    1-24 of 47 1 2 »
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    1. (47 articles) Chao Zhou
    2. (30 articles) Massachusetts Institute of Technology
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    4. (23 articles) Lehigh University
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    6. (15 articles) Harvard University
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    Three-dimensional endomicroscopy of the human colon using optical coherence tomography Frequency comb swept lasers High speed optical coherence microscopy with autofocus adjustment and a miniaturized endoscopic imaging probe Endoscopic 3D-OCT reveals buried glands following radiofrequency ablation of Barrett's esophagus Features of Sub-Epithelial Glandular Structures on Three-Dimensional Endoscopic Optical Coherence Tomography (3D-EOCT) After Endoscopic Mucosal Ablation Blood Flow Dynamics of One Cardiac Cycle and Relationship to Mechanotransduction and Trabeculation during Heart Looping Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University Post-doctoral Associate Position in Biophotonics / Biomedical Optical Imaging at Lehigh University Post-doctoral Associate Position in Biophotonics/Biomedical Optical Imaging at Lehigh University Feature Of The Week 10/15/2017: Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids Direct inverse linearization of piezoelectric actuator’s initial loading curve and its applications in full-field optical coherence tomography (FF-OCT) Peripapillary Retinal and Choroidal Perfusion in Nonarteritic Ischemic Optic Neuropathy Using Optical Coherence Tomography Angiography