1. Articles in category: Probes

    241-264 of 469 « 1 2 ... 8 9 10 11 12 13 14 ... 18 19 20 »
    1. Congratulations to Jian Ren from Caltech a Winner of a 2012 Student Travel Grant Award

      Congratulations to Jian Ren from  Caltech a Winner of a 2012 Student Travel Grant Award
      Jian Ren from the California Institute of Technology is one of four winners of the OCT News 2012 student travel grant awards (see prior announcement Here). Below is a summary of his work. Glaucoma is one type of ophthalmic diseases, where ocular hypertension damages optical nerve, making it the second leading cause of blindness worldwide. One major cause of Open Angle Glaucoma is the poor outflow of aqueous humor through the Trabecular Meshwork (TM). Potential treatments include the micro-bypass stents, which are implanted in the TM and shunt fluid directly to the Schlemm’s Canal (SC) to reduce intraocular pressure ...
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    2. Double common-path interferometer for flexible optical probe of optical coherence tomography

      Double common-path interferometer for flexible optical probe of optical coherence tomography

      A flexible curled optical cord is useful for a common-path optical coherence tomography (OCT) system because a bending-insensitive arbitrary length can be chosen for the endoscopic imaging probe. However, there has been a critical problem that the partial reflector needs to be placed in between the sample and the objective lens. It limits the structure design of optical probe and leads to a low transverse resolution OCT imaging. Instead of a conventional single common-path interferometer, we propose a novel double common-path interferometer configuration in order to generate an interference signal that is independent of the optical distance between the partial ...

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    3. Refractive index measurement of acute rat brain tissue slices using optical coherence tomography

      Refractive index measurement of acute rat brain tissue slices using optical coherence tomography
      An optical coherence tomography (OCT) system employing a microelectromechanical system (MEMS) mirror was used to measure the refractive index (RI) of anatomically different regions in acute brain tissue slices, in which viability was maintained. RI was measured in white-matter and grey-matter regions, including the cerebral cortex, putamen, hippocampus, thalamus and corpus callosum. The RI in the corpus callosum was found to be ~4% higher than the RIs in other regions. Changes in RI with tissue deformation were also measured in the cerebral cortex and corpus callosum under uniform compression (20-80% strain). For 80% strain, measured RIs increased nonlinearly by up ...
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    4. Feature Of The Week 12/11/11: University of Western Australia Demonstrates Ultrathin Side-Viewing Needle Probe for Optical Coherence Tomography

      Feature Of The Week 12/11/11: University of Western Australia Demonstrates Ultrathin Side-Viewing Needle Probe for Optical Coherence Tomography

      Researchers at the University of Western Australia (UWA) have set a new record for the smallest side-viewing OCT imaging needle by demonstrating an ultrathin 30G needle probe with an outer diameter of only 0.31 mm. OCT needle probes [1, 2] are an enabling technology which allows to overcome the inherent imaging depth limitation of OCT of about 2-3 mm in biological tissue. To minimize tissue damage and deformation when imaging delicate organs or small animals, it is desirable to use very thin needle sizes.The ultrathin 30G needle probe presented in this work is based on a simple all-fiber ...

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    5. Imaging of Breast Cancer with Optical Coherence Tomography Needle Probes: Feasibility and Initial Results

      Imaging of Breast Cancer with Optical Coherence Tomography Needle Probes: Feasibility and Initial Results

      Optical coherence tomography (OCT) is a high-resolution imaging modality with the potential to provide in situ assessment to distinguish normal from cancerous tissue. However, limited image penetration depth has restricted its utility. This paper demonstrates the feasibility of an OCT needle probe to perform interstitial imaging deep below the tissue surface. The side-facing needle probe comprises miniaturized focusing optics consisting of no-core and GRIN fiber encased within either a 22- or 23-gauge needle. 3D-OCT volumetric data sets were acquired by rotating and retracting the probe during imaging. We present the first published image of a human breast cancer tumor margin ...

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    6. A forward-imaging needle-type OCT probe for image guided stereotactic procedures

      A forward-imaging needle-type OCT probe for image guided stereotactic procedures
      A forward-imaging needle-type optical coherence tomography (OCT) probe with Doppler OCT (DOCT) capability has the potential to solve critical challenges in interventional procedures. A case in point is stereotactic neurosurgery where probes are advanced into the brain based on predetermined coordinates. Laceration of blood vessels in front of the advancing probe is an unavoidable complication with current methods. Moreover, cerebrospinal fluid (CSF) leakage during surgery can shift the brain rendering the predetermined coordinates unreliable. In order to address these challenges, we developed a forward-imaging OCT probe (740 μm O.D.) using a gradient-index (GRIN) rod lens that can provide real-time ...
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    7. Scanning and Tunable Micro-Optics for Endoscopic Optical Coherence Tomography

      Scanning and Tunable Micro-Optics for Endoscopic Optical Coherence Tomography
      The design, fabrication, and integration of micro-optical components for beam focus and steering are demonstrated in an endoscopic optical coherence tomography (OCT) system. The relevant components, a membrane-based microfluidic tunable microlens and an electrostatic 2-D scanning micromirror, are fabricated using silicon and polymer-based microelectromechanical system technologies. All components are assembled inside a 4.5 $muhbox{m}$ diameter probe. The design of the optical system, including substantiation of the need for focal length tunability, is presented, along with performance data of an OCT system using these components. A lateral resolution of about 13 $muhbox{m}$ is achieved, an improvement over fixed-focal ...
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    8. Feature Of The Week 11/27/11: Langevin Institute and LLTech Investigate In Vivo Cellular Full-Field OCT Imaging with a Rigid Endoscopic Probe

      Feature Of The Week 11/27/11: Langevin Institute and LLTech Investigate In Vivo Cellular Full-Field OCT Imaging with a Rigid Endoscopic Probe

      Full-Field OCT (FFOCT) is a particular approach of OCT that directly takes “en face” 2-D images with an isotropic resolution around 1µm [1]. With such a high resolution FFOCT systems can produce images that are similar to that obtained with classical histology procedures and can thus be important tools for pathology [2]. This is why we want to combine the interest of a setup with a needle probe with the performances of FFOCT.A FFOCT system with probe has to address the problem of keeping the performances of FFOCT in a setup using a miniaturized, medically safe probe. As proposed ...

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    9. Endoscope two dimensional scanning fiber probe and the driving method

      Endoscope two dimensional scanning fiber probe and the driving method
      We design and fabricate an endoscope scanning fiber probe based on the piezoelectric transducer (PZT) for optical coherence tomography (OCT) to perform two-dimensional scanning. The driving part of the optical fiber probe is composed of two piezoelectric ceramics and a thin conductive substrate. The optical fiber is fixed in the middle of the piezoelectric ceramics to form a configuration of cantilever. A sine wave is employed for driving the PZT to make the cantilever vibrate along the vertical direction and form a line scanning. A saw tooth wave is load on the PZT to make the cantilever vibrate along the ...
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    10. Catheter system and method for boring through blocked vascular passages

      Catheter system and method for boring through blocked vascular passages
      A rotating cutting head catheter for passage through chronic total occlusions or other refractory atherosclerotic plaque from diseased arteries is disclosed. The catheter's rotating cutting head is designed to reside safely within an outer protective sheath when not in use. The outer protective sheath contains one or more helical grooves or slots, and the cutting head contains protruding blades or projections that fit into these helical grooves or slots. Application of torque to an inner catheter or wire attached to the cutting head applies spin to the cutting head, and the force of the sheath's helical grooves or ...
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    11. Portable optical coherence tomography (OCT) devices and related systems

      Portable optical coherence tomography (OCT) devices and related systems
      Portable optical coherence tomography (OCT) devices including at least one mirror configured to scan at least two directions are provided. The portable OCT devices are configured to provide a portable interface to a sample that can be aligned to the sample without repositioning the sample. Related systems are also provided.
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    12. Numerical simulation of a gradient-index fibre probe and its properties of light propagation

      Numerical simulation of a gradient-index fibre probe and its properties of light propagation
      In order to verify the properties of the light propagating through a gradient-index (GRIN) fibre probe for optical coherence tomography (OCT), numerical simulation using the optical software GLAD is carried out. Firstly, the model of the GRIN fibre probe is presented, which is consisted of a single mode fibre (SMF), a no-core fibre (NCF), a GRIN fibre lens and an air path. Then, the software GLAD is adopted to numerically investigate how the lengths of the NCF and the GRIN fibre lens influence the performance of the Gaussian beam focusing through the GRIN fibre probe. The simulation results are well ...
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    13. Stationary-fiber rotary probe with unobstructed 360° view for optical coherence tomography

      Stationary-fiber rotary probe with unobstructed 360° view for optical coherence tomography
      A side-scanning fiber probe is a critical component for optical coherence tomography in medical imaging and diagnosis. We propose and fabricate an on-axis rotating probe that performs in situ, circumferential scanning that is shadow-free (not susceptible to shadow effects caused by the motor’s wires). A miniature motor that incorporates a bored-out shaft for the optical fiber is located at the distal end of the probe, which results in a more stable and uniform circumferential scan, free from wire-shadow interference effects. More importantly, this design, novel to our knowledge, compared to other probes avoids the insertion losses introduced by optical ...
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    14. Multimodal catheter system and method for intravascular analysis

      Multimodal catheter system and method for intravascular analysis
      Methods, apparatus, and systems for intravascular analysis combine at least three analytical modalities. In one implementation, intravascular ultrasound, optical coherence tomography, and near infrared spectroscopy are combined to enable detection of multiple, different abnormalities in the arterial morphology during a single intravascular procedure.
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      Mentions: InfraReDx
    15. High capacity debulking catheter with distal driven cutting wheel

      High capacity debulking catheter with distal driven cutting wheel
      An atherectomy catheter includes a rotary cutting knife that is driven from the distal (nose) or side (circumference) direction. The catheter collects plaque shavings in a hollow collection chamber mounted in between the rotary cutting knife and the main catheter tubing. In contrast to prior art designs, which utilized nose mounted plaque collection chambers, the present design is able to store a substantially larger volume of removed plaque, thus increasing the length of time and amount of plaque removal that can be accomplished before the catheter must be removed from the body and cleaned. This decreases medical procedure time, allows ...
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    16. Optical rotary adapter and optical tomographic imaging system using the same

      Optical rotary adapter and optical tomographic imaging system using the same
      The optical rotary adapter is used with an optical tomographic imaging system for acquiring an optical tomographic image of an object under measurement. The adapter includes a fixed sleeve, a stationary optical fiber supported by the fixed sleeve and having an inclined end face, a stationary collimating lens spaced a given distance from the inclined end face, a mounting cylinder carried rotatably with respect to the fixed sleeve, a rotary optical fiber mounted to the mounting cylinder and having an inclined end face, a rotary collimating lens mounted to the mounting cylinder and disposed with a given distance from the ...
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    17. Miniature Optical Elements For Fiber-Optic Beam Shaping

      Miniature Optical Elements For Fiber-Optic Beam Shaping
      In part, the invention relates to optical caps having at least one lensed surface configured to redirect and focus light outside of the cap. The cap is placed over an optical fiber. Optical radiation travels through the fiber and interacts with the optical surface or optical surfaces of the cap, resulting in a beam that is either focused at a distance outside of the cap or substantially collimated. The optical elements such as the elongate caps described herein can be used with various data collection modalities such optical coherence tomography. In part, the invention relates to a lens assembly that ...
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    18. Full-range Fourier domain optical coherence tomography imaging probe with a magnetic-driven resonant fiber cantilever

      Full-range Fourier domain optical coherence tomography imaging probe with a magnetic-driven resonant fiber cantilever
      In this work, we developed a full-range Fourier domain optical coherence tomography (FD-OCT) imaging probe with a magnetic-driven resonant fiber cantilever. A galvanometer-driven reference mirror provides a linear phase modulation to each M-scan/B-scan frame to enable complex conjugate-free, full-range FD-OCT imaging. A fiber cantilever inside the probe is driven by a low-voltage miniature magnetic transducer. The fiber cantilever scans at its resonant frequency synchronized to the phase modulation induced by the reference mirror. Using a CCD line-scan camera-based spectrometer, we demonstrated real-time full-range FD-OCT at 34 frame/s (1024 pixel lateral × 2048 pixel axial).
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    19. In vivo and in situ cellular imaging full-field optical coherence tomography with a rigid endoscopic probe

      In vivo and in situ cellular imaging full-field optical coherence tomography with a rigid endoscopic probe
      Full-field OCT has proved to be a powerful high-resolution cellular imaging tool for biological tissues. However the standard bulk full-field OCT setup does not match the size requirements for most in situ and in vivo imaging applications. We adapted its principle into a rigid needle-like probe using two coupled interferometers and incoherent illumination: an external processing interferometer is used for in-depth scanning, while a distal common-path interferometer at the tip of the probe collects light backscattered from the tissue. Our experimental setup achieves an axial and transversal resolution in tissue of 1.8 µm and 3.5 µm respectively, for ...
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    20. Multiple beam source for a multi-beam interferometer and multi-beam interferometer

      Multiple beam source for a multi-beam interferometer and multi-beam interferometer
      A multi-beam interferometer, typically for use in Optical Coherence Tomography, comprising a multiple beam source, the source being arranged so as to provide, in use, a plurality of beams of light for use in the interferometer, the source comprising: a light source arranged to, in use, emit a beam of light; and a rattle plate comprising a first reflective surface and a second reflective surface facing one another, the second reflective surface being only partially reflective.
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    21. Ultrathin side-viewing needle probe for optical coherence tomography

      Ultrathin side-viewing needle probe for optical coherence tomography

      We present the smallest reported side-viewing needle probe for optical coherence tomography (OCT). Design, fabrication, optical characterization, and initial application of a 30-gauge (outer diameter 0.31 mm) needle probe are demonstrated. Extreme miniaturization is achieved by using a simple all-fiber probe design incorporating an angle-polished and reflection-coated fiber-tip beam deflector. When inserted into biological tissue, aqueous interstitial fluids reduce the probe’s inherent astigmatism ratio to 1.8, resulting in a working distance of 300 μm and a depth-of-field of 550 μm with beam diameters below 30 μm. The needle probe was interfaced with an 840 nm spectral-domain OCT ...

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    22. What Are Safe Margins of Resection for Invasive and In Situ Breast Cancer?

      What Are Safe Margins of Resection for Invasive and In Situ Breast Cancer?
      equate surgical margins in breast-conserving surgery are an important predictor of local recurrence (LR) rates. The definition of tumor-free margins in National Surgical Adjuvant Breast and Bowel Project (NSABP) trials requires that tumor cells do not touch ink, but subsequent retrospective single-institution studies have suggested that wider margins confer greater protection against LR. Particularly wide margins have been proposed for ductal carcinoma in situ. However, wider margin requirements lead to higher re-excision rates, with attendant economic, psychological, and cosmetic costs, and perhaps increased mastectomy rates. Juxtaposed against these concerns about optimal margin width, a meta-analysis of clinical trials has demonstrated ...
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    23. Feature Of The Week 9/11/11: Researchers at University of Florida Probe Into Miniature MEMs for OCT Imaging

      Feature Of The Week 9/11/11: Researchers at University of Florida Probe Into Miniature MEMs for OCT Imaging
      Researchers at the University of Florida, let by Dr. Huikai Xie, have been active for many years in developing advanced optical scanning technology using MEMS technology. Such technology is important for OCT and other optical imaging modalities. Below is a summary of some of their recent work.Endoscopic optical coherence tomography (OCT) imaging is very useful since it can replace risky, painful and time-consuming biopsy. However Endoscopic OCT is also very challenging, because fast lateral optical scan must be realized in a small imaging probe that must be able to fit into the small biopsy channel of endoscopes. MEMS technology ...
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    1. (1 articles) University of Illinois at Urbana-Champaign
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  4. People in the News

    1. (1 articles) Stephen A. Boppart
    2. (1 articles) Guillermo L. Monroy
    3. (1 articles) Huikai K. Xie
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    5. (1 articles) Paritosh Pande
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