1. Articles in category: Microscopy

    1-24 of 508 1 2 3 4 ... 20 21 22 »
    1. Multimodal high-resolution embryonic imaging with light sheet fluorescence microscopy and optical coherence tomography

      Multimodal high-resolution embryonic imaging with light sheet fluorescence microscopy and optical coherence tomography

      A high-resolution imaging system combining optical coherence tomography (OCT) and light sheet fluorescence microscopy (LSFM) was developed. LSFM confined the excitation to only the focal plane, removing the out of plane fluorescence. This enabled imaging a murine embryo with higher speed and specificity than traditional fluorescence microscopy. OCT gives information about the structure of the embryo from the same plane illuminated by LSFM. The co-planar OCT and LSFM instrument was capable of performing co-registered functional and structural imaging of mouse embryos simultaneously.

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    2. PROSCOPE project aims for early-stage bowel cancer detection

      PROSCOPE project aims for early-stage bowel cancer detection

      Multimodal platform should allow cellular-level colon imaging in real-time. Improving diagnosis: PROSCOPE A project funded by the EU's Horizon 2020 program is on course to develop a new imaging system for the diagnosis of bowel cancer. PROSCOPE , officially titled "Point-of-care instrument for diagnosis and image-guided intervention of colorectal cancer," was launched in 2020 and backed by €6 million of EU funding. The project has now carried out an 18-month formal review, confirming that its research program is on target to help reduce the 160,000 deaths and €9 billion in healthcare costs associated with the disease. "Currently, only 14 ...

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    3. 1700 nm optical coherence microscopy enables minimally invasive, label-free, in vivo optical biopsy deep in the mouse brain

      1700 nm optical coherence microscopy enables minimally invasive, label-free, in vivo optical biopsy deep in the mouse brain

      In vivo, minimally invasive microscopy in deep cortical and sub-cortical regions of the mouse brain has been challenging. To address this challenge, we present an in vivo high numerical aperture optical coherence microscopy (OCM) approach that fully utilizes the water absorption window around 1700 nm, where ballistic attenuation in the brain is minimized. Key issues, including detector noise, excess light source noise, chromatic dispersion, and the resolution-speckle tradeoff, are analyzed and optimized. Imaging through a thinned-skull preparation that preserves intracranial space, we present volumetric imaging of cytoarchitecture and myeloarchitecture across the entire depth of the mouse neocortex, and some sub-cortical ...

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      Mentions: UC Davis
    4. Functional and structural ophthalmic imaging using noncontact multimodal photoacoustic remote sensing microscopy and optical coherence tomography

      Functional and structural ophthalmic imaging using noncontact multimodal photoacoustic remote sensing microscopy and optical coherence tomography

      Early diagnosis of ocular diseases improves the understanding of pathophysiology and aids in accurate monitoring and effective treatment. Advanced, multimodal ocular imaging platforms play a crucial role in visualization of ocular components and provide clinicians with a valuable tool for evaluating various eye diseases. Here, for the first time we present a non-contact, multiwavelength photoacoustic remote sensing (PARS) microscopy and swept-source optical coherence tomography (SS-OCT) for in-vivo functional and structural imaging of the eye. The system provides complementary imaging contrasts of optical absorption and optical scattering, and is used for simultaneous, non-contact, in-vivo imaging of murine eye. Results of vasculature ...

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    5. Speckle-dependent accuracy in phase-sensitive optical coherence tomography

      Speckle-dependent accuracy in phase-sensitive optical coherence tomography

      Phase-sensitive optical coherence tomography (OCT) is used to measure motion in a range of techniques, such as Doppler OCT and optical coherence elastography (OCE). In phase-sensitive OCT, motion is typically estimated using a model of the OCT signal derived from a single reflector. However, this approach is not representative of turbid samples, such as tissue, which exhibit speckle. In this study, for the first time, we demonstrate, through theory and experiment that speckle significantly lowers the accuracy of phase-sensitive OCT in a manner not accounted for by the OCT signal-to-noise ratio (SNR). We describe how the inaccuracy in speckle reduces ...

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    6. Microscope

      Microscope

      A microscope, comprising an observation beam path that renders an eye to be examined observable, a wavefront measuring device for measuring the refraction of the eye to be examined, an OCT device comprising an OCT illumination beam path, by means of which OCT illumination radiation can be focused as an OCT spot into the eye to be examined, and a control unit that is supplied with at least one measurement value of the wave front measuring device, is provided, wherein the control unit sets the beam diameter and/or the beam shape of the OCT spot on the basis of ...

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    7. Chain-like gold nanoparticle clusters for multimodal photoacoustic microscopy and optical coherence tomography enhanced molecular imaging

      Chain-like gold nanoparticle clusters for multimodal photoacoustic microscopy and optical coherence tomography enhanced molecular imaging

      Colloidal gold nanoparticles (GNPs) serve as promising contrast agents in photoacoustic (PA) imaging, yet their utility is limited due to their absorption peak in the visible window overlapping with that of hemoglobin. To overcome such limitation, this report describes an ultrapure chain-like gold nanoparticle (CGNP) clusters with a redshift peak wavelength at 650 nm. The synthesized CGNP show an excellent biocompatibility and photostability. These nanoparticles are conjugated with arginine-glycine-aspartic acid (RGD) peptides (CGNP clusters-RGD) and validated in 12 living rabbits to perform multimodal photoacoustic microscopy (PAM) and optical coherence tomography (OCT) for visualization of newly developed blood vessels in the ...

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    8. Indentation probe with optical fiber array-based optical coherence tomography for material deformation

      Indentation probe with optical fiber array-based optical coherence tomography for material deformation

      We present a new optomechanical probe for mechanical testing of soft matter. The probe consists of a micromachined cantilever equipped with an indenting sphere, and an array of 16 single‐mode optical fibers, which are connected to an Optical Coherence Tomography (OCT) system that allows sub‐surface analysis of the sample during the indentation stroke. To test our device and its capability, we performed indentation on a PDMS‐based phantom. Our findings demonstrate that Common Path (CP)‐OCT via lensed optical fibers can be successfully combined with a microindentation sensor to visualize the phantom's deformation profile at different indentation ...

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    9. Laser scanning reflection-matrix microscopy sees inside intact mouse skull

      Laser scanning reflection-matrix microscopy sees inside intact mouse skull

      Visualizing tissues and neurons inside an animal's skull has long been a challenge for biophotonics techniques, thanks to the skull's thickness and the complex structures inside. Approaches to this problem have included the use of endoscopic platforms in brain imaging, two-photon and three-photon microscopy of small animals, and for surgical purposes the creation of a transparent window in the skull itself. A team at the Institute for Basic Science ( IBS ) in Daejeon, South Korea, has now developed a new approach to tackling the optical aberrations involved in imaging through an intact skull, and tested the system on a ...

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    10. Optical comparison between micro-CT and OCT in imaging of marginal composite adaptation; Observational study

      Optical comparison between micro-CT and OCT in imaging of marginal composite adaptation; Observational study

      Dental composite is the most used aesthetic restorative biomaterial worldwide. However, it undergoes polymerization shrinkage that could lead to loss of the interfacial seal between tooth and resin in some circumstances. This demands high-resolution imaging technologies to detect these defects. This study carried out a comparison between microcomputed tomography (micro-CT; Shimadzu, Japan) and swept-source optical coherence tomography (SS-OCT; Santec, Japan) in the detection of marginal adaptation defects at the tooth-resin interface. Unlike in micro-CT, it was possible to outline interfacial gaps along with tooth-resin interfaces with SS-OCT, which was attributed to the Fresnel diffraction of light. This in-vitro comparison demonstrates ...

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    11. Multi-directional Morphological Assessment of Single Bacterial Colonies Through Non-invasive Optical Imaging

      Multi-directional Morphological Assessment of Single Bacterial Colonies Through Non-invasive Optical Imaging

      A bacterium in bacterial colony is a basal component of bacterial studies and is therefore of considerable importance. The morphological characteristics of a single colony have been widely used as the standard to identify diverse bacterial species. However, the conventional methods for obtaining morphological information, such as microscopic techniques, cannot provide tomographic views. This study utilizes spectral-domain optical coherence tomography (SD-OCT) to observe both external and internal structures for single colonies. OCT imaging provided a clear top (projection) and lateral (cross-sectional) images, which can identify distinct features in the fifteen different bacterial species examined. Through the acquired OCT images, the ...

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    12. Visualization of Bacterial Colonization and Cellular Layers in a Gut-on-a-Chip System Using Optical Coherence Tomography

      Visualization of Bacterial Colonization and Cellular Layers in a Gut-on-a-Chip System Using Optical Coherence Tomography

      Imaging of cellular layers in a gut-on-a-chip system has been confined to two-dimensional (2D)-imaging through conventional light microscopy and confocal laser scanning microscopy (CLSM) yielding three-dimensional- and 2D-cross-sectional reconstructions. However, CLSM requires staining and is unsuitable for longitudinal visualization. Here, we compare merits of optical coherence tomography (OCT) with those of CLSM and light microscopy for visualization of intestinal epithelial layers during protection by a probiotic Bifidobacterium breve strain and a simultaneous pathogen challenge by an Escherichia coli strain. OCT cross-sectional images yielded film thicknesses that coincided with end-point thicknesses derived from cross-sectional CLSM images. Light microscopy on histological ...

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    13. Optical coherence tomography microscopy in experimental traumatic brain injury

      Optical coherence tomography microscopy in experimental traumatic brain injury

      Worldwide elderly traumatic brain injury (TBI) patients tend to become an increasing burden to the society. Thus, a faster and less expensive way of evaluating TBI victims is needed. In the present study we investigated if optical coherence tomography (OCT) could be used as such a method. By using an animal model, we established if OCT can detect cortical changes in the acute phase of a penetrating TBI, in young (5-7 months) and old (20-22 months) rats. Due to the long-term evolution of TBI's, we wanted to investigate to what extent OCT could detect changes within the cortex in ...

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    14. Morphological, optical, and elemental analysis of dental enamel after debonding laminate veneer with Er,Cr:YSGG laser: A pilot study

      Morphological, optical, and elemental analysis of dental enamel after debonding laminate veneer with Er,Cr:YSGG laser: A pilot study

      Laminate veneer removal is becoming a routine procedure at the dental clinic and the use of laser can facilitate its removal. This work aimed to evaluate the morphological, elemental, and optical changes in the remaining enamel after veneer removal using Er,Cr:YSGG laser. Forty‐four enamel slabs were prepared and randomly distributed into nine experimental groups, for bonding using lithium disilicate laminates with three different luting agents (Variolink Veneer, RelyX U200, and RelyX Veneer). Then each agent was debonded using Er,Cr:YSGG laser (2.78 μm) using two different protocols:3.5 W, 48.14 J/cm 2 ...

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    15. High Resolution Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Visualization of Choroidal Vascular Occlusion

      High Resolution Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Visualization of Choroidal Vascular Occlusion

      Photoacoustic microscopy is a novel, non-ionizing, non-invasive imaging technology that evaluates tissue absorption of short-pulsed light through the sound waves emitted by the tissue and has numerous biomedical applications. In this study, a custom-built multimodal imaging system, including photoacoustic microscopy (PAM) and optical coherence tomography (OCT), has been developed to evaluate choroidal vascular occlusion (CVO). CVO was performed on three living rabbits using laser photocoagulation. Longitudinal imaging of CVO was obtained using multiple imaging tools such as color fundus photography, fluorescein angiography, indocyanine green angiography (ICGA), OCT, and PAM. PAM images were acquired at different wavelengths, ranging from 532 to ...

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    16. Role of Microscope-Intraoperative Optical Coherence Tomography in paediatric keratoplasty: A comparative Study

      Role of Microscope-Intraoperative Optical Coherence Tomography in paediatric keratoplasty: A comparative Study

      Purpose To evaluate role of Microscope-Integrated Intraoperative Optical Coherence Tomography (i-OCT) in paediatric keratoplasty. Design Combined prospective and retrospective, comparative, interventional study Setting Dr Rajendra Prasad Centre for Ophthalmic Sciences, India Methods Seventy-five children aged ≤16 years planned for keratoplasty were divided into two groups and compared for intraoperative course and postoperative outcome. In Group-1 (prospective group, n=56), pre-operative anterior segment visualization was performed clinically, with ultrasound biomicroscopy (UBM) and i-OCT and keratoplasty was commenced under i-OCT microscope. In Group-2 (retrospective group, n=19), conventional microscope was employed during keratoplasty. Results In Group-1, i-OCT, UBM and clinical examination detected ...

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    17. Laser Lens Size Measurement Using Swept-Source Optical Coherence Tomography

      Laser Lens Size Measurement Using Swept-Source Optical Coherence Tomography

      A high-speed, high-resolution swept-source optical coherence tomography (SS-OCT) is presented for focusing lens imaging and a k-domain uniform algorithm is adopted to find the wave number phase equalization. The radius of curvature of the laser focusing lens was obtained using a curve-fitting algorithm. The experimental results demonstrate that the measuring accuracy of the proposed SS-OCT system is higher than the laser confocal microscope.

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    18. What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

      What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

      Background: Optical coherence tomography (OCT) has recently been introduced in the operating theatre. The aim of this review is to present the actual role of microscope-integrated optical coherence tomography (MI-OCT) in ophthalmology. Method: A total of 314 studies were identified, following a literature search adhering to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. After full-text evaluation, 81 studies discussing MI-OCT applications in ophthalmology were included. Results: At present, three microscope-integrated optical coherence tomography systems are commercially available. MI-OCT can help anterior and posterior segment surgeons in the decision-making process, providing direct visualization of anatomic planes before ...

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    19. Light detection and ranging system with photonic integrated circuit

      Light detection and ranging system with photonic integrated circuit

      Disclosed herein are optical integration technologies, designs, systems and methods directed toward Optical Coherence Tomography (OCT) and other interferometric optical sensor, ranging, and imaging systems wherein such systems, methods and structures employ tunable optical sources, coherent detection and other structures on a single or multichip monolithic integration. In contrast to contemporary, prior-art OCT systems and structures that employ simple, miniature optical bench technology using small optical components positioned on a substrate, systems and methods according to the present disclosure employ one or more photonic integrated circuits (PICs), use swept-source techniques, and employ a widely tunable optical source(s). In another ...

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    20. Vectorial birefringence imaging by optical coherence microscopy for assessing fibrillar microstructures in the cornea and limbus

      Vectorial birefringence imaging by optical coherence microscopy for assessing fibrillar microstructures in the cornea and limbus

      The organization of fibrillar tissue on the micrometer scale carries direct implications for health and disease but remains difficult to assess in vivo . Polarization-sensitive optical coherence tomography measures birefringence, which relates to the microscopic arrangement of fibrillar tissue components. Here, we demonstrate a critical improvement in leveraging this contrast mechanism by employing the improved spatial resolution of focus-extended optical coherence microscopy (1.4 µm axially in air and 1.6 µm laterally, over more than 70 µm depth of field). Vectorial birefringence imaging of sheep cornea ex vivo reveals its lamellar organization into thin sections with distinct local optic axis ...

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    21. Computed optical coherence microscopy of mouse brain ex vivo

      Computed optical coherence microscopy of mouse brain ex vivo

      The compromise between lateral resolution and usable imaging depth range is a bottleneck for optical coherence tomography (OCT). Existing solutions for optical coherence microscopy (OCM) suffer from either large data size and long acquisition time or a nonideal point spread function. We present volumetric OCM of mouse brain ex vivo with a large depth coverage by leveraging computational adaptive optics (CAO) to significantly reduce the number of OCM volumes that need to be acquired with a Gaussian beam focused at different depths. We demonstrate volumetric reconstruction of ex-vivo mouse brain with lateral resolution of 2.2  μm, axial resolution of ...

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    22. Microscope having an optical coherence tomography device

      Microscope having an optical coherence tomography device

      A microscope having an observation beam path including a main objective, an OCT device including a first detection beam path, a wavefront measuring device including a second detection beam path, a first, a second and a third optics group is provided, wherein the first detection beam path contains the main objective and the first to third optics group, and the first to third optics group forms an afocal imaging optical unit of the first detection beam path and the second detection beam path contains the main objective, the first optics group and the second optics group, and the main objective ...

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    23. Combination of 2D Compressive Sensing Spectral Domain Optical Coherence Tomography and Interferometric Synthetic Aperture Microscopy

      Combination of 2D Compressive Sensing Spectral Domain Optical Coherence Tomography and Interferometric Synthetic Aperture Microscopy

      Combining the advantages of compressive sensing spectral domain optical coherence tomography (CS-SDOCT) and interferometric synthetic aperture microscopy (ISAM) in terms of data volume, imaging speed, and lateral resolution, we demonstrated how compressive sampling and ISAM can be simultaneously used to reconstruct an optical coherence tomography (OCT) image. Specifically, an OCT image is reconstructed from two-dimensional (2D) under-sampled spectral data dimension-by-dimension through a CS reconstruction algorithm. During the iterative process of CS algorithm, the deterioration of lateral resolution beyond the depth of focus (DOF) of a Gaussian beam is corrected. In the end, with less spectral data, we can obtain an ...

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    24. VIS-OCT offers sight line

      VIS-OCT offers sight line

      The benefits of optical coherence tomography (OCT) have long been known as an imaging tool in ophthalmology, enabling the examination of the eye at microscopic resolution. But what may not be widely appreciated is that the use of visible light sources can improve upon the results of this well-developed technique in the detection and understanding of various eye-related diseases such as macular degeneration and glaucoma. While most commercial OCT and OCTA (angiography) systems use NIR light for economic and technical reasons, broadband visible light sources have expanded from 400 to 2000 nm or more. This has enabled the imaging of ...

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