1. Dirk Lorenser

    0 Comments Leave a Comment

    1-17 of 17
    1. Mentioned In 17 Articles

    2. Two-photon polymerisation 3D printed freeform micro-optics for optical coherence tomography fibre probes

      Two-photon polymerisation 3D printed freeform micro-optics for optical coherence tomography fibre probes
      Miniaturised optical coherence tomography (OCT) fibre-optic probes have enabled high-resolution cross-sectional imaging deep within the body. However, existing OCT fibre-optic probe fabrication methods cannot generate miniaturised freeform optics, which limits our ability to fabricate probes with both complex optical function and dimensions comparable to the optical fibre diameter. Recently, major advances in two-photon direct laser writing have enabled 3D printing of arbitrary three-dimensional micro/nanostructures with a surface roughness acceptable ...
      Read Full Article
    3. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

      Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour
      Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign ...
      Read Full Article
    4. Quantifying the influence of Bessel beams on image quality in optical coherence tomography

      Quantifying the influence of Bessel beams on image quality in optical coherence tomography
      Light scattered by turbid tissue is known to degrade optical coherence tomography (OCT) image contrast progressively with depth. Bessel beams have been proposed as an alternative to Gaussian beams to image deeper into turbid tissue. However, studies of turbid tissue comparing the image quality for different beam types are lacking. We present such a study, using numerically simulated beams and experimental OCT images formed by Bessel or Gaussian beams illuminating ...
      Read Full Article
    5. Ultrahigh-resolution optical coherence elastography

      Ultrahigh-resolution optical coherence elastography
      Visualizing stiffness within the local tissue environment at the cellular and subcellular level promises to provide insight into the genesis and progression of disease. In this Letter, we propose ultrahigh-resolution optical coherence elastography (UHROCE), and demonstrate 3D imaging of local axial strain of tissues undergoing compressive loading. We combine optical coherence microscopy (OCM) and phase-sensitive detection of local tissue displacement to produce strain elastograms with resolution (
      Read Full Article
    6. Molecular imaging needles: dual-modality optical coherence tomography and fluorescence imaging of labeled antibodies deep in tissue

      Molecular imaging needles: dual-modality optical coherence tomography and fluorescence imaging of labeled antibodies deep in tissue
      ...David D. Sampson, Caroline Boudoux, and Robert A. McLaughlin »View Author Affiliations Loretta Scolaro,^1,^* Dirk Lorenser,^1 Wendy-Julie Madore,^2 Rodney W. Kirk,^1 Anne S. Kramer,^3 George C. Yeoh,^3 Nicolas Godbout,^...
      Read Full Article
    7. Imaging deep skeletal muscle structure using a high-sensitivity ultrathin side-viewing optical coherence tomography needle probe

      Imaging deep skeletal muscle structure using a high-sensitivity ultrathin side-viewing optical coherence tomography needle probe
      We have developed an extremely miniaturized optical coherence tomography (OCT) needle probe (outer diameter 310 m) with high sensitivity (108 dB) to enable minimally invasive imaging of cellular structure deep within skeletal muscle. Three-dimensional volumetric images were acquired from ex vivo mouse tissue, examining both healthy and pathological dystrophic muscle. Individual myofibers were visualized as striations in the images. Degradation of cellular structure in necrotic regions was seen as a ...
      Read Full Article
    8. Accurate Modeling and Design of Graded-Index Fiber Probes for Optical Coherence Tomography using the Beam Propagation Method

      Accurate Modeling and Design of Graded-Index Fiber Probes for Optical Coherence Tomography using the Beam Propagation Method
      Fiber-optic probes for sensing and biomedical imaging applications such as optical coherence tomography (OCT) frequently employ sections of graded-index (GRIN) fiber to re-focus the diverging light from the delivery fiber. Such GRIN fiber microlenses often possess aberrations that cause significant distortions of the focused output beam. Current design methods based on ABCD matrix transformations of Gaussian beams cannot model such effects and are therefore inadequate for the analysis and design ...
      Read Full Article
    9. 3D imaging of internal structures of skeletal muscle with an ultrathin side-viewing optical needle probe

      3D imaging of internal structures of skeletal muscle with an ultrathin side-viewing optical needle probe
      Evaluation of degradation in the structure of skeletal muscle is important for the assessment or diagnosis of many myopathies, such as Duchenne muscular dystrophy. Histological analysis is the gold standard to evaluate such degradation but requires excision and fixation of the tissue. This is undesirably invasive in patients and precludes longitudinal study of disease progression in patients or animal models. Optical coherence tomography (OCT) is a high-resolution (10m) imaging modality ...
      Read Full Article
    10. Static and dynamic imaging of alveoli using optical coherence tomography needle probes

      Static and dynamic imaging of alveoli using optical coherence tomography needle probes
      Imaging of alveoli in situ has for the most part been infeasible due to the high resolution required to discern individual alveoli and limited access to alveoli beneath the lung surface. In this study, we present a novel technique to image alveoli using optical coherence tomography (OCT). We propose the use of OCT needle probes, where the distal imaging probe has been miniaturized and encased within a hypodermic needle (as ...
      Read Full Article
    11. 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
      ...after the needle was retracted.For more information, please see recent Article and references below. Courtesy Dirk Lorenser.   [1] X. Li, C. Chudoba, T. Ko, C. Pitris, and J. G. Fujimoto, "Imaging needle for optica...
      Read Full Article
    12. 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- ...
      Read Full Article
    13. 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 0.31mm) 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 probes inherent astigmatism ratio to 1.8, resulting in a ...
      Read Full Article
    14. 1-17 of 17
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. About Dirk Lorenser

    Dirk Lorenser

    Dirk Lorenser received his PhD in applied laser physics from ETH Zurich in 2006, where he built mode-locked external-cavity semiconductor lasers at the Ultrafast Laser Physics group. After his PhD he spent three exciting years working in R&D for a Swiss ultrafast laser company called Onefive, which back then was still a young startup company and which has since then grown to become a well-established supplier of compact picosecond and femtosecond lasers. In 2009 he left Switzerland’s beautiful alpine scenery for the equally beautiful shores of Australia, where he is currently working as a research assistant professor at the University of Western Australia in the Optical + Biomedical Engineering Laboratory (OBEL). His main research interest is building novel biomedical optics instrumentation, such as needle-probe OCT systems or miniaturized fiber-optic confocal micro-endoscopes. Dirk loves Western Australia and whenever he’s got an opportunity to escape the lab you’ll find him bushwalking in the scenic countryside outside Perth with his wife Sandra