1. Articles in category: Probes

    241-264 of 403 « 1 2 ... 8 9 10 11 12 13 14 ... 15 16 17 »
    1. Measuring soft tissue elasticity by monitoring surface acoustic waves using image plane digital holography

      Measuring soft tissue elasticity by monitoring surface acoustic waves using image plane digital holography

      The detection of tumors in soft tissues, such as breast cancer, is important to achieve at the earliest stages of the disease to improve patient outcome. Tumors often exhibit a greater elastic modulus compared to normal tissues. In this paper, we report our first study to measure elastic properties of soft tissues by mapping the surface acoustic waves (SAWs) with image plane digital holography. The experimental results show that the SAW velocity is proportional to the square root of elastic modulus over a range from 3.7-122kPa in homogeneous tissue phantoms, consistent with Rayleigh wave theory. This technique also permits ...

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    2. Toward better treatment of clogged arteries

      Toward better treatment of clogged arteries
      Real-time detailed monitoring of angioplasty balloon deformation may lead to improved medical devices to treat hardened artery walls. Intravascular optical coherence tomography (IVOCT) is a catheter-based technique that provides detailed cross-sectional imaging of the artery wall with a resolution of the order of ten micrometers. The clinical relevance of IVOCT has been demonstrated in many studies for the diagnosis and treatment monitoring of atherosclerosis1 (hardening and/or thickening of arteries by deposited plaques of cholesterol and other lipids, inflammatory cells, and calcium deposits). The technology is mature enough to be distributed commercially.2 Images may be acquired during a ‘pullback ...
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    3. Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography

      Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography

      We developed a piezoelectric transducer (PZT) based miniature catheter with an outer diameter of 3 mm for ultrahigh speed endoscopic optical coherence tomography (OCT) using Fourier domain modelocked (FDML) laser at a 480 kHz axial scan rate. The miniaturized PZT bender actuates a fiber to provide high scanning speed. The side-viewing probe can be pulled back for a long distance to acquire three-dimensional (3D) dataset covering a large area on the specimen. Operating with a high speed data acquisition (DAQ) system, OCT imaging with 6.5 mm imaging range, 10 μm axial resolution, 20 μm lateral resolution, and frame rate ...

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    4. Integrated optical coherence tomography - ultrasound system and miniaturized probes for intravascular imaging

      Integrated optical coherence tomography - ultrasound system and miniaturized probes for intravascular imaging

      We report on the development of a multimodal optical coherence tomography (OCT) - ultrasound (US) system and miniaturized OCT-US probe for intravascular imaging. Both OCT optical components and a US transducer were integrated into a single probe, enabling both OCT and US imaging at the same time. A miniaturized OCT-US probe using a single element transducer was designed with a maximum outer diameter of 0.8 mm, which is suitable for in vivo intravascular imaging. The integrated OCT-US imaging system adopted a two-channel data acquisition card to digitize both OCT and US signals. Simultaneous OCT and US data processing and image ...

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    5. The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy

      The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy

      Interferometric synthetic aperture microscopy (ISAM) reconstructs the scattering potential of a sample with spatially invariant resolution, based on the incident beam profile, the beam scan pattern, the physical model of light sample interaction, and subsequent light collection by the system. In practice, aberrations may influence the beam profile, particularly at higher NA, when ISAM is expected to provide maximum benefit over optical coherence microscopy. Thus it is of interest to determine the effects of aberrations on ISAM reconstructions. In this paper we present the forward model incorporating the effects of aberrations, which forms the basis for aberration correction in ISAM ...

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    6. Characterization of optical fiber imaging bundles for swept-source optical coherence tomography

      Characterization of optical fiber imaging bundles for swept-source optical coherence tomography

      Fiber imaging bundles have been investigated for use in endoscopic optical coherence tomography (OCT) systems, to obviate the requirement for scanning components within the endoscope probe section. Images have been acquired using several optical configurations, two of which are common path in design. Configurations have been selected as having potential for miniaturization and inclusion in endoscopic-type systems, since the advantages of employing imaging bundles are most clearly seen in this type of system. The various types of bundle available are described, and the properties of the leached bundles used here are discussed in detail, with reference to their effect upon ...

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    7. Miniature endoscopic optical coherence tomography probe employing a two-axis microelectromechanical scanning mirror with through-silicon vias

      Miniature endoscopic optical coherence tomography probe employing a two-axis microelectromechanical scanning mirror with through-silicon vias
      We present the design and experimental results of a new MEMS-based endoscopic optical coherence tomography (OCT) probe. The uniqueness of this miniature OCT imaging probe is a two-axis MEMS mirror with through-silicon vias (TSVs) for interconnecting. The TSV interconnection enables ultracompact probe design, successfully reducing the probe size to only 2.6 mm in diameter. The MEMS mirror is actuated by an electrothermal actuator that is capable of scanning ±16° at only 3.6 V DC. Two-dimensional and three-dimensional OCT images of microspheres embedded in PDMS and acute rat brain tissue have been obtained with this miniature probe in a ...
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    8. Optical tomographic imaging apparatus and optical tomographic imaging method

      Optical tomographic imaging apparatus and optical tomographic imaging method
      In an optical tomographic imaging apparatus, a wavelength of a light beam emitted from the light source is selected by a light source section filter, and the light beam emitted from the light source is split into a measurement light beam and a reference light beam. The measurement light beam is reflected from a measurement subject when the measurement light beam is irradiated, is amplified. A specific wavelength from the amplified reflected light beam is selected by an amplifying section filtering mechanism having a filter characteristic identical to a time variation characteristic of the light source section filter, and then ...
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    9. Feature Of The Week 1/30/11: Development of Dual-Mode OCT and IVUS for Intravascular Imaging - A look at recent work from University of Southern California and UC Irvine

      Feature Of The Week 1/30/11: Development of Dual-Mode OCT and IVUS for Intravascular Imaging - A look at recent work from University of Southern California and UC Irvine
      Feature Of The Week 1/30/11: Multimodality imaging with OCT is a hot topic in general and at Photonics West in particular. This week’s “Feature Of The Week” is about integrated OCT and IVUS imaging. Below is a summary of work by researchers from the Viterbi School of Engineering at the University of Southern California and the Beckman Laser Institute and Department of Biomedical Engineering at the University of California, Irvine.The USC and UC Irvine researchers developed a dual-mode biomedical imaging probe utilizing intravascular ultrasound (IVUS) and optical coherence tomography (OCT). It consists of an OCT probe ...
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    10. Clinician: Enhanced depth imaging OCT assists in choroidal imaging

      Clinician: Enhanced depth imaging OCT assists in choroidal imaging
      Enhanced depth imaging optical coherence tomography produces choroidal imaging, which could offer a new understanding of multiple ocular diseases, including age-related choroidal atrophy, according to a speaker. "Historically, when we looked at OCT images, we had very good ability to delineate the retinal structures, but the choroid wasn't delineated very well. That's partly because the devices were designed to focus on the retina, not on the vitreous or the choroid," Ocular Surgery News Retina/Vitreous Board Member Peter K. Kaiser, MD, said at the Retina 2011 meeting. Enhanced depth imaging places the OCT close to the eye, he ...
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    11. Multi-angle and multi-channel inspecting device

      Multi-angle and multi-channel inspecting device
      A multi-angle and multi-channel detecting device for detecting one or more than one samples is provided. The device has a light collector and a multi-channel kernel module. The light collector has a plurality of fiber probes arranged perpendicular to and/or inclined to the sample(s) so as to collect light signals. The kernel module is coupled to the light collector for detecting the sample(s).
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    12. Numerical analysis of gradient index lens based optical coherence tomography imaging probes

      Numerical analysis of gradient index lens based optical coherence tomography imaging probes

      We report the numerical analysis of gradient index (GRIN) lens-based optical coherence tomography imaging probes to derive optimal design parameters. Long and short working distance probes with a small focal spot are considered. In each model, the working distance and beam waist are characterized and compared for different values of length and refractive index of the probe components. We also explore the influence of the outer tubing and refractive index of the sample media. Numerical results show that the adjustment of the maximum beam diameter and focusing angle at the end of the GRIN lens surface is very important for ...

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    13. A dual-modality probe utilizing intravascular ultrasound and optical coherence tomography for intravascular imaging applications

      A dual-modality probe utilizing intravascular ultrasound and optical coherence tomography for intravascular imaging applications
      We have developed a dual-modality biomedical imaging probe utilizing intravascular ultrasound (IVUS) and optical coherence tomography (OCT). It consists of an OCT probe, a miniature ultrasonic transducer and a fixed mirror. The mirror was mounted at the head of the hybrid probe 45° relative to the light and the ultrasound beams to change their propagation directions. The probe was designed to be able to cover a larger area in blood vessel by IVUS and then visualize a specific point at a much finer image resolution using OCT. To demonstrate both its feasibility and potential clinical applications, we used this ultrasound-guide ...
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    14. Optical coherence tomography apparatus and methods

      Optical coherence tomography apparatus and methods
      In one aspect, the invention relates to an imaging probe. The imaging probe includes an elongate body having a proximal end and distal end, the elongate body adapted to enclose a portion of a slidable optical fiber, the optical fiber having a longitudinal axis; and a first optical assembly attached to a distal end of the fiber. The first optical assembly includes a beam director adapted to direct light emitted from the fiber to a plane at a predetermined angle to the longitudinal axis, a linear actuator disposed at the proximal portion of the elongated body, the actuator adapted to ...
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    15. Construction and test of a GRIN-based optical objective

      Construction and test of a GRIN-based optical objective
      Optical fibres with their unique ability to transport light even in a coherent way (fibre bundles) and the possibility to build small volume optical pieces (Graded Index Fibres, GRIN) have a dominant role in the assembly of probes and objectives for microscopy applications requiring noninvasive and flexible operation in small and crowded spaces (in vivo microscopy, endoscopy, inspection). Nowadays, even complex observing procedures like confocal, two-photon and optical coherence tomography can be approached with fibres, making possible in vivo applications and also in place decision and processing. We present here a series of analytical simulations and practical tests made on ...
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    16. Rotating catheter probe using a light-drive apparatus

      Rotating catheter probe using a light-drive apparatus
      The invention is a rotating tip catheter-imaging probe where electromagnetic energy is delivered to the distal end of a catheter and converted to mechanical energy using a light drive apparatus. The mechanical energy is then used to rotate a mirror that redirects light in fixed pattern on a sample. The rotating element of the light drive apparatus contains vanes, which rotate about an axis and positioned with bearings to minimize friction. A chamber encompasses the rotating element and is set to a vacuum pressure. The rotational speed of the catheter tip can be controlled by varying the optical power delivered ...
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    17. Microfabricated endoscopic probe integrated MEMS micromirror for optical coherence tomography bioimaging

      Microfabricated endoscopic probe integrated MEMS micromirror for optical coherence tomography bioimaging
      In this paper, we present a miniaturized endoscopic probe, consisted of MEMS micromirror, silicon optical bench (SiOB), grade index (GRIN) lens, single mode optical fiber (SMF) and transparent housing, for optical coherence tomography (OCT) bioimaging. Due to the use of the MEMS micromirror, the endoscopic OCT system is highly suitable for non-invasive imaging diagnosis of a wide variety of inner organs. The probe engineering and proof of concept were demonstrated by obtaining the two-dimensional OCT images with a cover slide and an onion used as standard samples and the axial resolution was around 10µm.
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    18. Mini-scope for multi-directional imaging

      Mini-scope for multi-directional imaging
      A mini-scope for multi-directional imaging is disclosed. The mini-scope includes an elongated mini-scoped body. An emissions aperture is disposed on the distal end of the elongated mini-scope body, which can be configured to emit a beam of optical energy propagating through a flexible optical conductor. A selective mirror is also positioned at the distal end of the elongated mini-scope body and is configured to selectively pass or reflect the beam of optical energy based on the optical characteristics of the beam. A SSID is further disposed on the distal end of the elongated mini-scope body for imaging illumination reflected by ...
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    19. Optical design of a line-focused forward-viewing scanner for optical coherence tomography

      Optical design of a line-focused forward-viewing scanner for optical coherence tomography
      We report an optical design of a line-focused forward-viewing optical coherence tomography (OCT) scanner for high-speed endoscopic imaging. To avoid a complex lens system, an off-axis cylindrical mirror is used for focusing the line illumination onto the sample surface. Because of its insensitivity to the broadband spectrum, the mirror-focused scanner improves the image quality compared to a lens-focused scanner. In this work, a feasibility study is carried out on the use of a reflective-optics-focused line scanner in OCT imaging, instead of the traditional refractive optics scanner. The Strehl ratio, chromatic focal shift, and field analysis were carried out for a ...
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    20. Apparatus of measuring glucose concentration by using optical coherence tomography and method of operating the apparatus

      Apparatus of measuring glucose concentration by using optical coherence tomography and method of operating the apparatus
      Disclosed is an apparatus and method for measuring glucose concentration by using Optical Coherence Tomography (OCT), and more particularly, an apparatus and method for increasing the blood volume around a measurement part by using a blood concentrating device and noninvasively measuring glucose concentration of the measuring portion by using OCT. A glucose concentration measuring apparatus and method using OCT according to the invention can noninvasively measure glucose concentration by using OCT and help a user to easily measure glucose concentration.
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    21. Common path systems and methods for frequency domain and time domain optical coherence tomography using non-specular reference reflection and a delivering device for optical radiation with a partially optically transparent non-specular reference reflector

      Common path systems and methods for frequency domain and time domain optical coherence tomography using non-specular reference reflection and a delivering device for optical radiation with a partially optically transparent non-specular reference reflector
      Provided are common path frequency domain and time domain OCT systems and methods that use non-specular reference reflection for obtaining internal depth profiles and depth resolved images of samples. Further provided is a delivering device for optical radiation, preferably implemented as an optical fiber probe with a partially optically transparent non-specular reflector placed in the vicinity of an associated sample. High frequency fringes are substantially reduced and a stable power level of the reference reflection is provided over the lateral scanning range. The partially optically transparent non-specular reflector is implemented as a coating placed on the interior surface of the ...
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    22. New collaboration targets skin cancer with hybrid imaging probe

      New collaboration targets skin cancer with hybrid imaging probe

      A new collaboration between researchers at King’s Health Partners Academic Health Sciences Centre and an innovative British company is targeting skin cancer with a new type of imaging probe. The £98,500 research project has received 75% funding through a National Institute for Health Research (NIHR) Invention for Innovation ‘i4i’ grant awarded to the partners, Guy’s and St Thomas’ NHS Foundation Trust, King’s College London and Michelson Diagnostics Ltd.   The aim of the project is to develop and test a hybrid imaging probe that combines the advantages of Michelson Diagnostics’ novel Multi-Beam OCT (Optical Coherence Tomography) probe ...

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    23. OCT probe for eliminating ghost images

      OCT probe for eliminating ghost images
      An OCT probe has a sheath to be inserted into a subject; and an optical system within the sheath, for changing the direction of light which propagates from a light source through an optical fiber to irradiate the light onto the subject through a transparent portion of the sheath, and for reflecting the light beam, which is reflected by the subject, to guide the light into the optical fiber. A light output surface, for causing the light to be output from the reflecting surface in a direction obliquely inclined with respect to the inner surface of the sheath, and a ...
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    24. High-resolution coregistered intravascular imaging with integrated ultrasound and optical coherence tomography probe

      High-resolution coregistered intravascular imaging with integrated ultrasound and optical coherence tomography probe
      We report an integrated ultrasound (US) and optical coherence tomography (OCT) probe and system for intravascular imaging. The dual-function probe is based on a 50 MHz focused ring US transducer, with a centric hole for mounting OCT probe. The coaxial US and light beams are steered by a 45° mirror to enable coregistered US/OCT imaging simultaneously. Lateral resolution of US is improved due to focused ultrasonic beam. Mirror effects on US were investigated and in vitro imaging of a rabbit aorta has been carried out. The combined US-OCT system demonstrated high resolution in visualizing superficial arterial structures while retaining ...
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