1. Articles in category: Probes

    241-264 of 450 « 1 2 ... 8 9 10 11 12 13 14 ... 17 18 19 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. Design optimization and implementation of a miniature optical coherence tomography probe based on a MEMS mirror

      Design optimization and implementation of a miniature optical coherence tomography probe based on a MEMS mirror
      Optical coherence tomography (OCT) provides non-invasive cross-sectional imaging capability and high resolution, but it has very limited applications inside human body because of the stringent size requirements for accessing the internal organs. Micro-Electro-Mechanical Systems (MEMS) is an emerging technology that can make devices with small size and fast speed. This paper reports the design optimization of a MEMS mirror-based miniature OCT probe. The probe consists of three main parts: a GRIN lens module (1.3 mm in diameter), a MEMS mirror (1.7 mm x 1.55 mm), and a stainless steel mount. A special assembly holder is designed for ...
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    7. Common-path low-coherence interferometry fiber-optic sensor guided microincision

      Common-path low-coherence interferometry fiber-optic sensor guided microincision
      We propose and demonstrate a common-path low-coherence interferometry (CP-LCI) fiber-optic sensor guided precise microincision. The method tracks the target surface and compensates the tool-to-surface relative motion with better than ±5 μm resolution using a precision micromotor connected to the tool tip. A single-fiber distance probe integrated microdissector was used to perform an accurate 100 μm incision into the surface of an Intralipid phantom. The CP-LCI guided incision quality in terms of depth was evaluated afterwards using three-dimensional Fourier-domain optical coherence tomography imaging, which showed significant improvement of incision accuracy compared to free-hand-only operations.
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    8. Analytical method for designing gradient-index fiber probes

      Analytical method for designing gradient-index fiber probes
      An analytical method was investigated to design the gradient-index (GRIN) fiber probe based on characteristic parameters of a Gaussian beam propagating through the probe. First, a typical model of the GRIN fiber probe was presented, consisting of a single mode fiber, a no-core fiber (NCF), and a GRIN fiber lens. Second, a complex beam parameter matrix transformation method was adopted to derive the mathematical expressions of characteristic parameters, such as beam waist location, beam waist radius, and Rayleigh range. Then, MATLAB software was used to analyze the impact of the length of NCF and the length of the GRIN fiber ...
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    9. Catheters for optical coherence tomography

      Catheters for optical coherence tomography

      The objective of this review article is to overview technology, clinical evidence, and future applications to date optical coherence tomography (OCT) probes to yield the diagnostic purpose. We have reviewed the designing, construction and working of different categories of OCT probes developed for optical diagnostics having a potential for non invasive and improved detection of different types of cancer as well as other neoplasm. Rotational and balloon catheters, imaging needles and hand-held, linear scanning, multichannel, micro electro mechanical systems (MEMS) technology based, dynamic focusing, forward view imaging, and common path interferometer based probes have been discussed in details. The fiber ...

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    10. Microball lens integrated fiber probe for optical frequency domain imaging

      Microball lens integrated fiber probe for optical frequency domain imaging
      An integrated microball lens fiber catheter probe is demonstrated, which has better lateral resolution and longer working distance than a corresponding bare fiber probe with diverging beam for Fourier domain optical coherence tomography (FDOCT). Simulation results are shown to gain the effect of the distance between the microball lens and the bare fiber to the focusing plane and beam width. The freedom of modifying the working distance and lateral resolution is shown. This is achieved by changing the gap distance between the single-mode fiber and the microball lens within the packaged surgical needle catheter without using an additional beam expander ...
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    11. Scientists awarded grant to continue developing optical device for medical exams

      Scientists awarded grant to continue developing optical device for medical exams

      Primary-care physicians could be using a handheld device that combines the functions of several tools at once, all linked to massive data storage, within the decade. The National Institutes of Health have awarded a team led by the University of Illinois $5 million over five years — with a renewal options — to improve the UI's optical tomography tool. The handheld tool can scope and make video of ears, eyes, cervical tissue and skin with only the change of a tip, and enter the bloodstream with fiber cable attached. Professor Stephen A. Boppart of the Beckman Institute is the principal investigator ...

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    12. New Diagnostic Imaging Technologies in Nonvariceal Upper Gastrointestinal Bleeding

      New Diagnostic Imaging Technologies in Nonvariceal Upper Gastrointestinal Bleeding
      This article covers new endoscopic imaging modalities in nonvariceal upper gastrointestinal bleeding, such as Doppler ultrasound probe technology, endoscopic ultrasonography, color Doppler optical coherence tomography, and magnification endoscopy. A more in-depth discussion of these modalities and the published evidence supporting their use are included. Furthermore, the shift in focus from identification of conventional visual surface stigmata of recent hemorrhage to an assessment and understanding of subsurface blood flow as it relates to the bleeding lesion is discussed.
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    13. Optical coherence tomography / acoustic radiation force imaging probe

      Optical coherence tomography / acoustic radiation force imaging probe
      combined system and method synchronizes optical coherence tomography and acoustic radiation force for simultaneously imaging and mechanically displacing tissue in a patient as a detection and analytic tool. An endoscope is provided which has a piezoelectric element and an OCT scanner. The piezoelectric element generates the acoustic force to displace the tissue. The OCT scanner images the tissue and the system determines the mechanical displacement of the tissue. Cancer and arterial plaques can be recognized from the mechanical displacement of the tissue.
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    14. Depixelation of coherent fiber bundle endoscopy based on learning patterns of image prior

      Depixelation of coherent fiber bundle endoscopy based on learning patterns of image prior
      We present an iterative method of eliminating pixelation artifacts from an endoscopic image acquired from a coherent fiber bundle imager. Our proposed approach for decoupling the honeycomb effect from the obtained sample image was formulated by using the prior probability for an approximate Bayesian framework in which the ideal complete image can be estimated by maximizing the posterior probability from the observed image. The maximization of the posterior probability from the original mask image (the mirrored fiber bundle imager structure) and the observed image (the sample image of the United States Air Force chart) has been performed by learning the ...
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    15. Intravascular Optical Coherence Tomography System With Pressure Monitoring Interface And Accessories

      Intravascular Optical Coherence Tomography System With Pressure Monitoring Interface And Accessories
      An optical coherence tomography system and method with integrated pressure measurement. In one embodiment the system includes an interferometer including: a wavelength swept laser; a source arm in communication with the wavelength swept laser; a reference arm in communication with a reference reflector; a first photodetector having a signal output; a detector arm in communication with the first photodetector, a probe interface; a sample arm in communication with a first optical connector of the probe interface; an acquisition and display system comprising: an A/D converter having a signal input in communication with the first photodetector signal output and a ...
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    16. Multiphoton Fluorescence Microscopy with GRIN Objective Aberration Correction by Low Order Adaptive Optics

      Multiphoton Fluorescence Microscopy with GRIN Objective Aberration Correction by Low Order Adaptive Optics

      Graded Index (GRIN) rod microlenses are increasingly employed in the assembly of optical probes for microendoscopy applications. Confocal, two–photon and optical coherence tomography (OCT) based on GRIN optical probes permit in–vivo imaging with penetration depths into tissue up to the centimeter range. However, insertion of the probe can be complicated by the need of several alignment and focusing mechanisms along the optical path. Furthermore, resolution values are generally not limited by diffraction, but rather by optical aberrations within the endoscope probe and feeding optics. Here we describe a multiphoton confocal fluorescence imaging system equipped with a compact objective ...

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    17. Needle stylet with integrated optical fibers for spectroscopic contrast during peripheral nerve blocks

      Needle stylet with integrated optical fibers for spectroscopic contrast during peripheral nerve blocks
      The effectiveness of peripheral nerve blocks is highly dependent on the accuracy at which the needle tip is navigated to the target injection site. Even when electrical stimulation is utilized in combination with ultrasound guidance, determining the proximity of the needle tip to the target region close to the nerve can be challenging. Optical reflectance spectroscopy could provide additional information about tissues that is complementary to these navigation methods. We demonstrate a novel needle stylet for acquiring spectra from tissue at the tip of a commercial 20-gauge needle. The stylet has integrated optical fibers that deliver broadband light to tissue ...
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    18. Electrostatically driven image probe

      Electrostatically driven image probe
      The present invention provides an imaging probe for imaging mammalian tissues and structures using high resolution imaging, including ultrasound and optical coherence tomography. The imaging probe uses electrostatic discharge for actuating a metalized cantilever which holds the end portion of imaging assembly which emits energy in the imaging probe device by holding the cantilever at a potential such that it is neither grounded or charged such that the only electrical path to ground is through a dissipative polymer forming part of the device which is enveloped by a wire or coil held at ground potential. A high voltage electrode attracts ...
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    19. Differential-phase polarization-sensitive optical coherence tomography system

      Differential-phase polarization-sensitive optical coherence tomography system
      A differential-phase polarization-sensitive optical coherence tomography system includes a polarized heterodyne interferometer for generating a reference beam to be reflected by a movable mirror unit, and a signal beam to be reflected by an imaging plane in a specimen. The interferometer further generates a first electrical signal output corresponding to first linear polarized waves of the reference and signal beams, and a second electrical signal output corresponding to second linear polarized waves of the reference and signal beams. A differential amplifier receives the first and second electrical signal outputs, and generates a differential signal output therefrom. A data acquisition unit ...
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    20. Catheters for optical coherence tomography

      Catheters for optical coherence tomography
      The objective of this review article is to overview technology, clinical evidence, and future applications to date optical coherence tomography (OCT) probes to yield the diagnostic purpose. We have reviewed the designing, construction and working of different categories of OCT probes developed for optical diagnostics having a potential for non invasive and improved detection of different types of cancer as well as other neoplasm. Rotational and balloon catheters, imaging needles and hand-held, linear scanning, multichannel, micro electro mechanical systems (MEMS) technology based, dynamic focusing, forward view imaging, and common path interferometer based probes have been discussed in details. The fiber ...
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    21. Design of a handheld optical coherence microscopy endoscope

      Design of a handheld optical coherence microscopy endoscope
      Optical coherence microscopy (OCM) combines coherence gating, high numerical aperture optics, and a fiber-core pinhole to provide high axial and lateral resolution with relatively large depth of imaging. We present a handheld rigid OCM endoscope designed for small animal surgical imaging, with a 6-mm diam tip, 1-mm scan width, and 1-mm imaging depth. X-Y scanning is performed distally with mirrors mounted to micro galvonometer scanners incorporated into the endoscope handle. The endoscope optical design consists of scanning doublets, an afocal Hopkins relay lens system, a 0.4 numerical aperture water immersion objective, and a cover glass. This endoscope can resolve ...
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    22. Optical coherence tomography device and measuring head

      Optical coherence tomography device and measuring head
      An optical coherence tomography device includes: a light source 16; a light splitting section 19 that splits light source light into reference light 19 and measuring light 28 with which a sample 22 is irradiated; an interfering section 19 that allows the measuring light 28 to interfere with the reference light 29 to generate interference light; a photodetectiong section 26 that measures interference light; a movable measuring head 201 that changes the irradiating position and/or direction, irradiated with the measuring light 28, by a motion of the measuring head 20; a mechanical quantity sensor 38 that measures the motion ...
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    23. Potential role of a hybrid intraoperative probe based on OCT and positron detection for ovarian cancer detection and characterization

      Potential role of a hybrid intraoperative probe based on OCT and positron detection for ovarian cancer detection and characterization
      Ovarian cancer has the lowest survival rate of the gynecologic cancers because it is predominantly diagnosed in the late stages due to the lack of reliable symptoms and efficacious screening techniques. A novel hybrid intraoperative probe has been developed and evaluated for its potential role in detecting and characterizing ovarian tissue. The hybrid intraoperative dual-modality device consists of multiple scintillating fibers and an optical coherence tomography imaging probe for simultaneously mapping the local activities of 18F-FDG uptake and imaging of local morphological changes of the ovary. Ten patients were recruited to the study and a total of 18 normal, abnormal ...
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    241-264 of 450 « 1 2 ... 8 9 10 11 12 13 14 ... 17 18 19 »
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