1. Articles in category: Probes

    1-24 of 513 1 2 3 4 ... 20 21 22 »
    1. Review: Optical Scanning Probe for Optical Coherence Tomography

      Review: Optical Scanning Probe for Optical Coherence Tomography

      Optical coherence tomography (OCT) has become an important medical imaging modality. However, low penetration depth limits its application. Therefore, the optical scanning probe plays an important role in OCT systems for clinical applications. This article reviews OCT methodology and the mechanisms of an optical scanning probe. Recent developments of OCT probe and related clinical applications are summerized. Various OCT probe techniques (e.g., side imaging and forward imaging) have been used for measuring optical biopsy of various tissues. OCT probes for early diagnosis applications should be developed and combined with functional OCT modalities, such as Doppler OCT and polarization-sensitive OCT ...

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    2. Multimodality endoscopic optical coherence tomography and fluorescence imaging technology for visualization of layered architecture and subsurface microvasculature

      Multimodality endoscopic optical coherence tomography and fluorescence imaging technology for visualization of layered architecture and subsurface microvasculature

      Endoscopic imaging technologies, such as endoscopic optical coherence tomography (OCT) and near-infrared fluorescence, have been used to investigate vascular and morphological changes as hallmarks of early cancer in the gastrointestinal tract. Here we developed a high-speed multimodality endoscopic OCT and fluorescence imaging system. Using this system, the architectural morphology and vasculature of the rectum wall were obtained simultaneously from a Sprague Dawley rat in vivo . This multimodality imaging strategy in a single imaging system permits the use of a single imaging probe, thereby improving prognosis by early detection and reducing costs.

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    3. A System for Clinical Use of Endoscopic Optical Coherence Tomography

      A System for Clinical Use of Endoscopic Optical Coherence Tomography

      Introduction: Optical Coherence Tomography (OCT) allows non-invasive high-resolution imaging of tissues. With a penetration depth of a few millimeters it's possible to image the tympanic membrane and the close-by part of the tympanum, e.g. for diagnostics of otitis media and middle ear effusion. In the field of in vivo examination there are difficulties in access to the human tympanic membrane due to the narrow and curved external ear canal. We report a compact endoscopic OCT system for use in clinical research. Methods: We use a 3,5 mm endoscopic GRIN lens for video endoscopy and OCT. OCT is ...

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    4. Feature of The Week 04/27/2018: Miniaturized single-fiber-based needle probe for combined imaging and sensing in deep tissue

      Feature of The Week 04/27/2018: Miniaturized single-fiber-based needle probe for combined imaging and sensing in deep tissue

      The ability to visualize structure while simultaneously measuring chemical or physical properties of a biological tissue has the potential to improve our understanding of complex biological processes. We report the first miniaturized single-fiber-based imaging+sensing probe capable of simultaneous optical coherence tomography (OCT) imaging and temperature sensing. An OCT lens is fabricated at the distal end of a double-clad fiber, including a thin layer of rare-earth-doped tellurite glass to enable temperature measurements. The high refractive index of the tellurite glass enables a common-path interferometer configuration for OCT, allowing easy exchange of probes for biomedical applications. The simultaneous imaging+sensing capability ...

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    5. Passively Driven Probe Based on Miniaturized Propeller for Intravascular Optical Coherence Tomography

      Passively Driven Probe Based on Miniaturized Propeller for Intravascular Optical Coherence Tomography

      Optical coherent tomography (OCT) has enabled clinical applications ranging from ophthalmology to cardiology that revolutionized in vivo medical diagnostics in the last few decades, and a variety of endoscopic probes have been developed in order to meet the needs of various endoscopic OCT imaging. We propose a passive driven intravascular optical coherent tomography (IV-OCT) probe in this paper. Instead of using any electrically driven scanning device, the probe makes use of the kinetic energy of the fluid that flushes away the blood during the intravascular optical coherence tomography imaging. The probe converts it into the rotational kinetic energy of the ...

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    6. Circumferential-scanning endoscopic optical coherence tomography probe based on a circular array of six 2-axis MEMS mirrors

      Circumferential-scanning endoscopic optical coherence tomography probe based on a circular array of six 2-axis MEMS mirrors

      We present a novel circumferential-scan endoscopic optical coherence tomography (OCT) probe by using a circular array of six electrothermal microelectromechanical (MEMS) mirrors and six C-lenses. The MEMS mirrors have a 0.5 mm × 0.5 mm mirror plate and a chip size of 1.5 mm × 1.3 mm. Each MEMS mirror can scan up to 45° at a voltage of less than 12 V. Six of those mirrors have been successfully packaged to a probe head; full circumferential scans have been demonstrated. Furthermore, each scan unit is composed of a MEMS mirror and a C-lens and the six scan ...

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      Mentions: Huikai K. Xie
    7. Miniaturized single-fiber-based needle probe for combined imaging and sensing in deep tissue

      Miniaturized single-fiber-based needle probe for combined imaging and sensing in deep tissue

      The ability to visualize structure while simultaneously measuring chemical or physical properties of a biological tissue has the potential to improve our understanding of complex biological processes. We report the first miniaturized single-fiber-based imaging + sensing imaging+sensing probe capable of simultaneous optical coherence tomography (OCT) imaging and temperature sensing. An OCT lens is fabricated at the distal end of a double-clad fiber, including a thin layer of rare-earth-doped tellurite glass to enable temperature measurements. The high refractive index of the tellurite glass enables a common-path interferometer configuration for OCT, allowing easy exchange of probes for biomedical applications. The simultaneous imaging ...

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    8. Reduced back reflection optical coherence tomography probe

      Reduced back reflection optical coherence tomography probe

      A beam-shaping optical system suitable for use with optical coherence tomography including a sheath defining a central cavity, a beam-shaping insert defining a beam-shaping element positioned within the central cavity, and an optical fiber having a core and a cladding. The optical fiber defines an angularly prepared fiber end configured to emit an electromagnetic beam toward the beam-shaping element with the core of the optical fiber locally expanded at the fiber end.

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      Mentions: Corning
    9. A 2.8-mm-diameter scanhead for multispectral photoacoustic microscopy and optical coherence tomography

      A 2.8-mm-diameter scanhead for multispectral photoacoustic microscopy and optical coherence tomography

      An endoscopic probe with high resolution and multiple contrasts provides useful diagnostic information. For example, a miniature probe capable of multimodal imaging including photoacoustic imaging, optical coherence tomography (OCT), and ultrasound has been reported. However, microscale resolution is only realized in OCT modality in the probe, which may restrict the applications where high resolutions for multiple contrasts are required. Here, we present an approach to construct a miniature scanhead with 2.8 mm in diameter that achieves high-resolution multispectral photoacoustic microscopy (PAM) and OCT. The method realizes high resolution of ∼10 μm for both PAM and OCT. We experimentally demonstrate ...

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    10. Endoscopic optical coherence tomography with a flexible fiber bundle

      Endoscopic optical coherence tomography with a flexible fiber bundle

      We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle. In comparison to current conventional forward looking probe schemes, our approach simplifies the endoscope design by avoiding the integration of any beam steering components in the distal probe end due to 2D scanning of a focused light beam over the proximal fiber bundle surface. We describe the challenges that arise when OCT imaging with a fiber bundle is performed, such as multimoding or cross-coupling. The performance of different fiber bundles with varying parameters such as numerical aperture, core size and core ...

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    11. Lights, camera, action! New endomicroscopic probes visualize living animal cell activity

      Lights, camera, action! New endomicroscopic probes visualize living animal cell activity

      Johns Hopkins researchers report they have developed two new endoscopic probes that significantly sharpen the technology’s imaging resolution and permit direct observation of fine tissue structures and cell activity in small organs in sheep, rats and mice. If clinical trials affirm the instruments’ value in humans, the researchers say, the scopes could one day reduce our dependence on invasive biopsies for diagnosing cancer and other diseases. “These tools are able to look into organs, such as the bile duct, pancreas and lungs, giving us a faster and safer way to diagnose a variety of diseases,” says Xingde Li, Ph ...

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    12. In vivo broadband visible light optical coherence tomography probe enables inverse spectroscopic analysis

      In vivo broadband visible light optical coherence tomography probe enables inverse spectroscopic analysis

      We report the design and characterization of a 6 mm outer diameter pull-back circumferential scanning visible optical coherence tomography probe. The probe’s large visible bandwidth (500–695 nm) allowed for inverse spectroscopic analysis and an axial resolution of ∼ 1.1    μm ∼1.1  μm in tissue. We verify spectral imaging capabilities by measuring microsphere backscattering spectra and demonstrate in vivo spatial nanoscale characterization of tissue.

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    13. Investigation of tissue cellularity at the tip of the core biopsy needle with optical coherence tomography

      Investigation of tissue cellularity at the tip of the core biopsy needle with optical coherence tomography

      We report the development and the pre-clinical testing of a new technology based on optical coherence tomography (OCT) for investigating tissue composition at the tip of the core biopsy needle. While ultrasound, computed tomography, and magnetic resonance imaging are routinely used to guide needle placement within a tumor, they still do not provide the resolution needed to investigate tissue cellularity (ratio between viable tumor and benign stroma) at the needle tip prior to taking a biopsy core. High resolution OCT imaging, however, can be used to investigate tissue morphology at the micron scale, and thus to determine if the biopsy ...

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    14. Novel endoscope with increased depth of field for imaging human nasal tissue by microscopic optical coherence tomography

      Novel endoscope with increased depth of field for imaging human nasal tissue by microscopic optical coherence tomography

      Intravital microscopy (IVM) offers the opportunity to visualize static and dynamic changes of tissue on a cellular level. It is a valuable tool in research and may considerably improve clinical diagnosis. In contrast to confocal and non-linear microscopy, optical coherence tomography (OCT) with microscopic resolution (mOCT) provides intrinsically cross-sectional imaging. Changing focus position is not needed, which simplifies especially endoscopic imaging. For in-vivo imaging, here we are presenting endo-microscopic OCT (emOCT). A graded-index-lens (GRIN) based 2.75 mm outer diameter rigid endoscope is providing 1.5 – 2 µm nearly isotropic resolution over an extended field of depth. Spherical and chromatic ...

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    15. Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo

      Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo

      Devices that perform wide field-of-view (FOV) precision optical scanning are important for endoscopic assessment and diagnosis of luminal organ disease such as in gastroenterology. Optical scanning for in vivo endoscopic imaging has traditionally relied on one or more proximal mechanical actuators, limiting scan accuracy and imaging speed. There is a need for rapid and precise two-dimensional (2D) microscanning technologies to enable the translation of benchtop scanning microscopies to in vivo endoscopic imaging. We demonstrate a new cycloid scanner in a tethered capsule for ultrahigh speed, side-viewing optical coherence tomography (OCT) endomicroscopy in vivo . The cycloid capsule incorporates two scanners: a ...

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    16. All-fiber probe for optical coherence tomography with an extended depth of focus by a high-efficient fiber-based filter

      All-fiber probe for optical coherence tomography with an extended depth of focus by a high-efficient fiber-based filter

      Although methods have been proposed to maintain high transverse resolution over an increased depth range, it is not straightforward to scale down the bulk-optic solutions to minimized probes of optical coherence tomography (OCT). In this paper, we propose a high-efficient fiber-based filter in an all-fiber OCT probe to realize an extended depth of focus (DOF) while maintaining a high transverse resolution. Mode interference in the probe is exploited to modulate the complex field with controllable radial distribution. The principle of DOF extension by the fiber-based filter is theoretically analyzed. Numerical simulations are conducted to evaluate the performances of the designed ...

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    17. Ergonomic Transducer Design for Endoscopic Optical Coherence Tomography

      Ergonomic Transducer Design for Endoscopic Optical Coherence Tomography

      Number of applications for optical MEMS, specifically MEMS with reflecting mirrors increased dramatically in recent years covering areas of optical communication (optical switches), robotics, medical devices, transportation systems, etc. Design of versatile optical transducers with mirrors capable to provide wide range of deflections yet with minimized energy consumption in smaller territory occupied on the semiconductor chip became to be a paramount concern for MEMS designers. Our design describes an optical actuator, where a mirror is installed at a 200µm long lever. On the opposite side of the lever there is a plate of capacitor used to activate lever moves ...

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    18. Broadband rotary joint for high-speed ultrahigh-resolution endoscopic OCT imaging at 800  nm

      Broadband rotary joint for high-speed ultrahigh-resolution endoscopic OCT imaging at 800  nm

      We report the development of a broadband rotary joint for high-speed ultrahigh-resolution endoscopic optical coherence tomography (OCT) imaging in the 800 nm spectral range. This rotary joint features a pair of achromatic doublets in order to achieve broadband operation for a 3 dB bandwidth over 150 nm. The measured one-way throughput of the rotary joint is greater than 80%, while the fluctuation of the double-pass coupling efficiency during 360 deg rotation is less than ± 5 % ±5% at a near video-rate speed of 20 revolutions/s (rps). The rotary joint is used in conjunction with a diffractive-optics-based endoscope and 800 nm ...

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    19. Methods and apparatus for utilizing impeller-based rotationally-scanning catheters

      Methods and apparatus for utilizing impeller-based rotationally-scanning catheters

      An ablation catheter includes a tubular catheter body having a lumen, a tip portion, a liquid inlet, at least one liquid outlet, a liquid flow path defined between the liquid inlet and the liquid outlet, and an ablation element mounted on the tip portion of the catheter body. A rotationally-scanning ultrasound assembly is disposed within the lumen of the catheter body adjacent the tip portion. The ultrasound assembly includes an ultrasound transducer having an active face, an acoustic mirror acoustically coupled to the active face of the ultrasound transducer, and an impeller positioned in the liquid flow path and operably ...

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      Mentions: St. Jude Medical
    20. Apparatus and method of image registration

      Apparatus and method of image registration

      A method for bringing an IVUS and an OCT image into register. In one embodiment, the method includes obtaining an IVUS image of an area of a lumen; obtaining an OCT image of the same area of the lumen; determining the same asymmetry in each of the IVUS and OCT images; and overlaying the IVUS and OCT images and rotating them with respect to one another until the asymmetry in each of the IVUS and OCT images are in register, and determining the angle of rotation that resulted in the registration. In another aspect, the invention relates to a probe ...

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    21. In-line optical fiber metallic mirror reflector for monolithic common path optical coherence tomography probes

      In-line optical fiber metallic mirror reflector for monolithic common path optical coherence tomography probes

      Background and Objectives Endoscopic optical coherence tomography probes suffer from various artifacts due to dispersion imbalance and polarization mismatch between reference and sample arm light. Such artifacts can be minimized using a common path approach. In this work, we demonstrate a miniaturized common path probe for optical coherence tomography using an inline fiber mirror. Materials and Methods A common path optical fiber probe suitable for performing high-resolution endoscopic optical coherence tomography imaging was developed. To achieve common path functionality, an inline fiber mirror was fabricated using a thin gold layer. A commercially available swept source engine was used to test ...

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    22. Systems, methods and apparatuses for real-time anastomosis guidance and surgical evaluation using optical coherence tomography

      Systems, methods and apparatuses for real-time anastomosis guidance and surgical evaluation using optical coherence tomography

      A surgical evaluation and guidance system for use in extravacular evaluation and guidance of fluid vessel surgeries, includes an optical coherence tomography engine; a vessel probe optically coupled to the optical coherence tomography engine; and a signal processing and display system adapted to communicate with the optical coherence tomography engine to receive imaging signals therefrom. An optical coherence tomography vessel probe for use in extravacular evaluation and guidance of fluid vessel surgeries, includes a probe body having a proximal end and a distal end; an optical relay system disposed within the probe body; and a vessel adapter at least one ...

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    23. Anticipating, measuring, and minimizing MEMS mirror scan error to improve laser scanning microscopy's speed and accuracy

      Anticipating, measuring, and minimizing MEMS mirror scan error to improve laser scanning microscopy's speed and accuracy

      We describe a method to speed up m icro e lectro m echanical s ystem (MEMS) mirror scanning by > 20x, while also improving scan accuracy. We use Landweber deconvolution to determine an input voltage which would produce a desired output, based on the measured MEMS impulse response. Since the MEMS is weakly nonlinear, the observed behavior deviates from expectations, and we iteratively improve our input to minimize this deviation. This allows customizable MEMS angle vs. time with <1% deviation from the desired scan pattern. We demonstrate our technique by optimizing a point scanning microscope’s raster patterns to image mammal ...

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    24. New Digital Servo Driver Improves Speed and Precision for Laser Beam Steering

      New Digital Servo Driver Improves Speed and Precision for Laser Beam Steering

      ambridge Technology, a business unit of Novanta Corporation ("Novanta"), announced today the launch of the DC3000 Plus, a new digital servo driver, adding to its product family of components and scan heads for laser beam steering. The DC3000 Plus builds on the success of its predecessor, the DC3000, which applies digital state space controller technology to optimize speed in laser marking applications. With increased drive current and improved thermal management, the DC3000 Plus now offers higher marking speed and it accurately drives larger mirrors faster. These improvements expand the product line's capabilities in laser converting, micromachining, high power welding ...

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    1-24 of 513 1 2 3 4 ... 20 21 22 »
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    1. (1 articles) Julia Walther
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