1. Articles in category: Microscopy

    1-24 of 460 1 2 3 4 ... 18 19 20 »
    1. Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy

      Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy

      Cell mechanical behaviour is increasingly recognised as a central biophysical parameter in cancer and stem cell research, and methods of investigating their mechanical behaviour are therefore needed. We have developed a novel qualitative method based on quantitative phase imaging which is capable of investigating cell mechanical behaviour in real-time at cellular resolution using optical coherence phase microscopy (OCPM), and stimulating the cells non-invasively using hydrostatic pressure. The method was exemplified to distinguish between cells with distinct mechanical properties, and transient change induced by Cytochalasin D. We showed the potential of quantitative phase imaging to detect nanoscale intracellular displacement induced by ...

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    2. Spectrally Encoded Coherence Tomography and Reflectometry (SECTR): simultaneous en face and cross-sectional imaging at 2 gigapixels-per-second

      Spectrally Encoded Coherence Tomography and Reflectometry (SECTR): simultaneous en face and cross-sectional imaging at 2 gigapixels-per-second

      Non-invasive biological imaging is crucial for understanding in vivo structure and function. Optical coherence tomography (OCT) and reflectance confocal microscopy are two of the most widely used optical modalities for exogenous contrast-free high-resolution three-dimensional imaging in non-fluorescent scattering tissues. However, sample motion remains a critical barrier to raster-scanned acquisition and reconstruction of wide-field anatomically accurate volumetric datasets. We introduce spectrally encoded coherence tomography and reflectometry (SECTR), a high-speed multimodality system for simultaneous OCT and spectrally-encoded reflectance (SER) imaging. SECTR utilizes a robust system design consisting of shared optical relays, scanning mirrors, swept-laser, and digitizer to achieve the fastest reported in ...

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    3. Microscope-integrated intraoperative optical coherence tomography-guided small-incision lenticule extraction: New surgical technique

      Microscope-integrated intraoperative optical coherence tomography-guided small-incision lenticule extraction: New surgical technique

      We describe the surgical technique of microscope-integrated intraoperative optical coherence tomography (OCT)-guided small-incision lenticule extraction. The technique enables manual tracking of surgical instruments and identification of the desired dissection plane. It also helps discern the relation between the dissector and the intrastromal lenticule. The dissection plane becomes hyperreflective on dissection, ensuring complete separation of the intrastromal lenticule from the overlying and underlying stroma. Inadvertent posterior plane entry, cap–lenticule adhesion, incomplete separation of the lenticule, creation of a false plane, and lenticule remnants may be recognized intraoperatively so corrective steps can be taken immediately. In cases with a hazy ...

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    4. Methods and systems for characterizing laser machining properties by measuring keyhole dynamics using interferometry

      Methods and systems for characterizing laser machining properties by measuring keyhole dynamics using interferometry

      A method, apparatus, and system are provided to monitor and characterize the dynamics of a phase change region (PCR) created during laser welding, specifically keyhole welding, and other material modification processes, using low-coherence interferometry. By directing a measurement beam to multiple locations within and overlapping with the PCR, the system, apparatus, and method are used to determine, in real time, spatial and temporal characteristics of the weld such as keyhole depth, length, width, shape and whether the keyhole is unstable, closes or collapses. This information is important in determining the quality and material properties of a completed finished weld. It ...

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    5. In vivo multiphoton microscopy using a handheld scanner with lateral and axial motion compensation

      In vivo multiphoton microscopy using a handheld scanner with lateral and axial motion compensation

      This paper reports a handheld multiphoton fluorescence microscope designed for clinical imaging that incorporates axial motion compensation and lateral image stabilization. Spectral domain optical coherence tomography is employed to track the axial position of the skin surface, and lateral motion compensation is realised by imaging the speckle pattern arising from the optical coherence tomography beam illuminating the sample. Our system is able to correct lateral sample velocities of up to ~65 μm s -1 . Combined with the use of negative curvature microstructured optical fibre to deliver tunable ultrafast radiation to the handheld multiphoton scanner without the need of a dispersion ...

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    6. Label-free three-dimensional imaging of Caenorhabditis elegans with visible optical coherence microscopy

      Label-free three-dimensional imaging of Caenorhabditis elegans with visible optical coherence microscopy

      Fast, label-free, high-resolution, three-dimensional imaging platforms are crucial for high-throughput in vivo time-lapse studies of the anatomy of Caenorhabditis elegans , one of the most commonly used model organisms in biomedical research. Despite the needs, methods combining all these characteristics have been lacking. Here, we present label-free imaging of live Caenorhabditis elegans with three-dimensional sub-micrometer resolution using visible optical coherence microscopy (visOCM). visOCM is a versatile optical imaging method which we introduced recently for tomography of cell cultures and tissue samples. Our method is based on Fourier domain optical coherence tomography, an interferometric technique that provides three-dimensional images with high sensitivity ...

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    7. Microscopic surgery system and navigation method guided by optical coherence tomography (OCT) and automated OCT imaging field calibration

      Microscopic surgery system and navigation method guided by optical coherence tomography (OCT) and automated OCT imaging field calibration

      Provided are a microscopic surgery system and a navigation method guided by optical coherence tomography. The microscopic surgery system may include: an object lens; a surgical microscope unit configured to perform two-dimensional imaging on an area to operate on via the object lens; an optical coherence tomography unit configured to perform two-dimensional tomography imaging on the area via the object lens, with an imaging field calibrated according to that of the surgical microscope unit; a processor configured to obtain navigation information based on the two-dimensional imaging by the surgical microscope unit and the two-dimensional tomography imaging by the optical coherence ...

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    8. Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers’ ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging techniques and provides unique access to fundamental aspects of early embryonic development, without the requirement for sample pre-processing or labeling. In the present paper, we utilized the internal motion of ...

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    9. Temporal evolution of low-coherence reflectrometry signals in photoacoustic remote sensing microscopy

      Temporal evolution of low-coherence reflectrometry signals in photoacoustic remote sensing microscopy

      Recently, a new noncontact reflection-mode imaging modality called photoacoustic remote sensing (PARS) microscopy was introduced providing optical absorption contrast. Unlike previous modalities, which rely on interferometric detection of a probe beam to measure surface oscillations, the PARS technique detects photoacoustic initial pressures induced by a pulsed laser at their origin by monitoring intensity modulations of a reflected probe beam. In this paper, a model describing the temporal evolution from a finite excitation pulse is developed with consideration given to the coherence length of the interrogation beam. Analytical models are compared with approximations, finite-difference time-domain (FDTD) simulations, and experiments with good ...

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    10. When pressure meets light: detecting the photoacoustic effect at the origin

      When pressure meets light: detecting the photoacoustic effect at the origin

      Modern optical microscopy1, including confocal microscopy, two-photon microscopy and optical coherence tomography (OCT), has revolutionized life sciences by providing detailed information of biological samples with cellular and subcellular resolutions, and has become an essential tool for biomedical research labs. However, optical microscopy typically has a limited penetration depth of ~1mm in biological tissue due to strong optical scattering23. Moreover, with respective contrast mechanisms, confocal and two-photon microscopy usually rely on fluorescent labeling of the samples and OCT still lacks sensitivity to many biological functions. In contrast, optical-resolution photoacoustic microscopy (OR-PAM) has emerged over the last decade ...

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      Mentions: Duke University
    11. Perth Researchers Developed the World's Smallest Microscope

      Perth Researchers Developed the World's Smallest Microscope

      One in four women who have a lump removed from their breast needs more surgery to remove remaining cancer cells. That’s a pretty scary statistic for patients. And it’s one Professor David Sampson believes could be better. “One of the main reasons [breast cancer patients need extra surgery] is because all of the tumour is not being identified. Because it can’t all be seen. Because you don’t have the resolution to see it.” David explains. “So in many instances, resolution – being able to see very small things – is a key part of improving those guidance procedures ...

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    12. Advances in Surgical Microscopes Pave the Way to Improved Outcomes

      Advances in Surgical Microscopes Pave the Way to Improved Outcomes

      The new generation of devices can heighten resolution, integrate patient data with intraoperative images and allow for more exact localization of surgical targets. By integrating intelligence, video, intraoperative-imaging and navigation technologies, today’s surgical microscopes provide surgeons with insights to improve their decision-making at the point of care and provide patients with the best possible outcomes. Surgical microscopes enable physicians to perform delicate surgery through tiny incisions. With a microscope, a surgeon can visualize anatomy within small cavities not perceptible by the human eye alone. They have long been used for ophthalmology.

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    13. Microscope-Integrated OCT Feasibility and Utility With the EnFocus System in the DISCOVER Study

      Microscope-Integrated OCT Feasibility and Utility With the EnFocus System in the DISCOVER Study

      BACKGROUND AND OBJECTIVE: To evaluate the feasibility and utility of a novel microscope-integrated intraoperative optical coherence tomography (OCT) system. PATIENTS AND METHODS: The DISCOVER study is an investigational device study evaluating microscope-integrated intraoperative OCT systems for ophthalmic surgery. This report focuses on subjects imaged with the EnFocus prototype system (Leica Microsystems/Bioptigen, Morrisville, NC). OCT was performed at surgeon-directed milestones. Surgeons completed a questionnaire after each case to evaluate the impact of OCT on intraoperative management. RESULTS: Fifty eyes underwent imaging with the EnFocus system. Successful imaging was obtained in 46 of 50 eyes (92%). In eight cases (16%), surgical ...

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    14. 3D wide field-of-view Gabor-domain optical coherence microscopy advancing real-time in-vivo imaging and metrology

      3D wide field-of-view Gabor-domain optical coherence microscopy advancing real-time in-vivo imaging and metrology

      Real-time volumetric high-definition wide-field-of-view in-vivo cellular imaging requires micron-scale resolution in 3D. Compactness of the handheld device and distortion-free images with cellular resolution are also critically required for onsite use in clinical applications. By integrating a custom liquid lens-based microscope and a dual-axis MEMS scanner in a compact handheld probe, Gabor-domain optical coherence microscopy (GD-OCM) breaks the lateral resolution limit of optical coherence tomography through depth, overcoming the tradeoff between numerical aperture and depth of focus, enabling advances in biotechnology. Furthermore, distortion-free imaging with no post-processing is achieved with a compact, lightweight handheld MEMS scanner that obtained a 12-fold reduction ...

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    15. White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

      White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

      A whole rodent brain was imaged using an automated massive histology setup and an Optical Coherence Tomography (OCT) microscope. Thousands of OCT volumetric tiles were acquired, each covering a size of about 2.5x2.5x0.8 mm3 with a sampling resolution of 4.9x4.9x6.5 microns. This paper shows the techniques for reconstruction, attenuation compensation and segmentation of the sliced brains. The tile positions within the mosaic were evaluated using a displacement model of the motorized stage and pairwise coregistration. Volume blending was then performed by solving the 3D Laplace equation, and consecutive slices were assembled using the cross-correlation ...

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    16. Optical coherence microscopy with extended focus for in vivo embryonic imaging

      Optical coherence microscopy with extended focus for in vivo embryonic imaging

      Optical coherence microscopy (OCM) has unique advantages of high-resolution volumetric imaging without relying on exogenous labels or dyes. It combines the coherence-gated depth discrimination of optical coherence tomography (OCT) with the high lateral resolution of confocal microscopy, offering an excellent balance between the resolutions and imaging depth. However, as the lateral resolution becomes higher, the imaging depth of OCM decreases and its three-dimensional imaging capability is greatly degraded. To overcome this limitation, we used amplitude apodization to create quasi-Bessel beam illumination in order to extend the depth of focus. The lateral and axial resolutions of our OCM system were measured ...

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    17. Optical coherence tomography technique

      Optical coherence tomography technique

      An optical coherence tomography device comprises a light generator, a dispersive medium, an optical coupler and a detector. The light generator is adapted to generate a series of input pulses of coherent light, each input pulse having an input pulse width. The dispersive medium has an input that is optically coupled to the light generator and an output for output pulses. The dispersive medium is adapted to stretch the input pulse width to an output pulse width of each of the output pulses by chromatic dispersion. The optical coupler is adapted to couple the output pulses into a reference arm ...

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      Mentions: Henning Wisweh
    18. Measurement of dynamic cell-induced 3D displacement fields in vitro for traction force optical coherence microscopy

      Measurement of dynamic cell-induced 3D displacement fields in vitro for traction force optical coherence microscopy

      Traction force microscopy (TFM) is a method used to study the forces exerted by cells as they sense and interact with their environment. Cell forces play a role in processes that take place over a wide range of spatiotemporal scales, and so it is desirable that TFM makes use of imaging modalities that can effectively capture the dynamics associated with these processes. To date, confocal microscopy has been the imaging modality of choice to perform TFM in 3D settings, although multiple factors limit its spatiotemporal coverage. We propose traction force optical coherence microscopy (TF-OCM) as a novel technique that may ...

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    19. Articular Cartilage Surface Topography and Roughness in Frozen Tissue Samples Using Optical Coherence Microscopy

      Articular Cartilage Surface Topography and Roughness in Frozen Tissue Samples Using Optical Coherence Microscopy

      This paper describes a method to visualize the topography of the surface of cartilage. Optical Coherence Microscopy (OCM) technique has been used to get two dimensional images of frozen tissue samples of bovine articular cartilage. Optical Coherence Microscopy (OCM) is a combination of optical coherence tomography and confocal microscopy. Coherence gate from OCT and confocal gate from confocal microscopy can achieve higher resolution and deeper penetration depth. The precise three-dimensional topography of the cartilage surfaces has been obtained. The full-image roughness, for frozen samples has been obtained.

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    20. Microscope-less wide field-of-view surgical OCT visualization system

      Microscope-less wide field-of-view surgical OCT visualization system

      A surgical imaging system can comprise a light source, configured to generate an imaging light beam; a beam guidance system, configured to guide the imaging light beam from the light source; a beam scanner, configured to receive the imaging light from the beam guidance system, and to generate a scanned imaging light beam; a beam coupler, configured to redirect the scanned imaging light beam; and a wide field of view (WFOV) lens, configured to guide the redirected scanned imaging light beam into a target region of a procedure eye.

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      Mentions: Lingfeng Yu
    21. En face coherence microscopy [Invited]

      En face coherence microscopy [Invited]

      En face coherence microscopy or flying spot or full field optical coherence tomography or microscopy (FF-OCT/FF-OCM) belongs to the OCT family because the sectioning ability is mostly linked to the source coherence length. In this article we will focus our attention on the advantages and the drawbacks of the following approaches: en face versus B scan tomography in terms of resolution, coherent versus incoherent illumination and influence of aberrations, and scanning versus full field imaging. We then show some examples to illustrate the diverse applications of en face coherent microscopy and show that endogenous or exogenous contrasts can add ...

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    22. Postdoctoral Research Fellowships in In Vivo Microscopy at Massachusetts General Hosptial

      Postdoctoral Research Fellowships in In Vivo Microscopy at Massachusetts General Hosptial

      Employer Description Until recently, visualizing the architectural and cellular morphology of human tissue has required histopathological examination. Samples would be excised from the patient, processed, sectioned, stained and viewed under a microscope. In addition to being invasive, time consuming and costly, the static nature of conventional pathology prohibits the study of biological dynamics and function. The Tearney Laboratory at Massachusetts General Hospital has led the way in transforming the current diagnostic paradigm through the invention and translation of new noninvasive, high-resolution optical imaging modalities that enable disease diagnosis from living patients without excising tissues from the body. Led by Guillermo ...

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    1-24 of 460 1 2 3 4 ... 18 19 20 »
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