1. Ton G. van Leeuwen

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    1. Mentioned In 86 Articles

    2. AMC and LioniX International partner on development of OCT modules

      AMC and LioniX International partner on development of OCT modules
      LioniX International (LXI) and Academic Medical Center (AMC) of the University of Amsterdam are collaborating on the development of Photonic Integrated Circuit-based Optical Coherence Tomography modules. The partners say that the implementation of PIC-based technologies in OCT modules will enable miniaturized handheld OCT modules and so broaden the scope and application of OCT-based systems. AMC and LXI have signed a collaboration agreement to accelerate the development of PIC-based OCT modules ...
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    3. Can we predict necrosis intra-operatively? Real-time optical quantitative perfusion imaging in surgery: study protocol for a prospective, observational, in vivo pilot study

      Can we predict necrosis intra-operatively? Real-time optical quantitative perfusion imaging in surgery: study protocol for a prospective, observational, in vivo pilot study
      Background Compromised perfusion as a result of surgical intervention causes a reduction of oxygen and nutrients in tissue and therefore decreased tissue vitality. Quantitative imaging of tissue perfusion during reconstructive surgery, therefore, may reduce the incidence of complications. Non-invasive optical techniques allow real-time tissue imaging, with high resolution and high contrast. The objectives of this study are, first, to assess the feasibility and accuracy of optical coherence tomography (OCT), sidestream ...
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    4. OCT Amplitude and Speckle Statistics of Discrete Random Media

      OCT Amplitude and Speckle Statistics of Discrete Random Media
      Speckle, amplitude fluctuations in optical coherence tomography (OCT) images, contains information on sub-resolution structural properties of the imaged sample. Speckle statistics could therefore be utilized in the characterization of biological tissues. However, a rigorous theoretical framework relating OCT speckle statistics to structural tissue properties has yet to be developed. As a first step, we present a theoretical description of OCT speckle, relating the OCT amplitude variance to size and organization ...
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    5. Visibility of Fiducial Markers used for Image-Guided Radiation Therapy on Optical Coherence Tomography for Registration with CT: an Esophageal Phantom Study

      Visibility of Fiducial Markers used for Image-Guided Radiation Therapy on Optical Coherence Tomography for Registration with CT: an Esophageal Phantom Study
      Purpose Optical coherence tomography (OCT) is of interest to visualize microscopic esophageal tumor extensions to improve tumor delineation for radiation therapy (RT) planning. Fiducial marker placement is a common method to ensure target localization during planning and treatment. Visualization of these fiducial markers on OCT permits integrating OCT and computed tomography (CT) images used for RT planning via image registration. We studied the visibility of 13 (8 types) commercially available ...
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    6. Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography

      Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography
      . Patient morbidity and mortality due to hemodynamic complications are a major problem in surgery. Optical techniques can image blood flow in real-time and high-resolution, thereby enabling perfusion monitoring intraoperatively. We tested the feasibility and validity of laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), and sidestream dark-field microscopy (SDF) for perfusion diagnostics in a phantom model using whole blood. Microvessels with diameters of 50, 100, and 400 m were ...
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    7. The amplitude and the phase or: Measuring directional and random motion with optical coherence tomography (Thesis)

      The amplitude and the phase or: Measuring directional and random motion with optical coherence tomography (Thesis)
      Optical coherence tomography (OCT) uses a low coherence light source and a Michelson interferometer to measure path-length resolved backscatter profiles of samples with micrometer resolution and up to a few millimeters long. The OCT amplitude is typically used to generate images of the sample. Additionally, the amplitude and the phase of the OCT signal can be used to extract quantitative sample information such as layer thickness, refractive index, and flow ...
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    8. Optical Coherence Tomography as a Tool for in Vivo Staging and Grading of Upper Urinary Tract Urothelial Carcinoma: A Study for Diagnostic Accuracy

      Optical Coherence Tomography as a Tool for in Vivo Staging and Grading of Upper Urinary Tract Urothelial Carcinoma: A Study for Diagnostic Accuracy
      Purposes Biopsies and cytology are cornerstones in the diagnosis of upper urinary tract urothelial carcinoma (UTUC). However, a high rate of non-diagnostic biopsies, tumor upgrading and -staging after nephroureterectomy is observed. In this prospective in vivo study we aimed to evaluate the diagnostic accuracy of OCT for grading and staging of UTUC Material Methods Twenty-six patients underwent diagnostic URS including biopsies and OCT imaging, followed by nephroureterectomy or segmental ureter ...
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    9. Chip based common-path optical coherence tomography system with an on-chip microlens and multi-reference suppression algorithm

      Chip based common-path optical coherence tomography system with an on-chip microlens and multi-reference suppression algorithm
      We demonstrate an integrated optical probe including an on-chip microlens for a common-path swept-source optical coherence tomography system. This common-path design uses the end facet of the silicon oxynitride waveguide as the reference plane, thus eliminating the need of a space-consuming and dispersive on-chip loop reference arm, thereby obviating the need for dispersion compensation. The on-chip micro-ball lens eliminates the need of external optical elements for coupling the light between ...
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    10. Prostate cancer diagnosis by optical coherence tomography: First results from a needle based optical platform for tissue sampling

      Prostate cancer diagnosis by optical coherence tomography: First results from a needle based optical platform for tissue sampling
      The diagnostic accuracy of Optical Coherence Tomography (OCT) based optical attenuation coefficient analysis is assessed for the detection of prostate cancer. Needle-based OCT-measurements were performed on the prostate specimens. Attenuation coefficients were determined by an earlier described in-house developed software package. The mean attenuation coefficients (benign OCT data; malignant OCT data; p-value Mann-Whitney U test) were: (3.56 mm 1 ; 3.85 mm 1 ; p 0.0001) for all patients ...
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    11. Customized Tool for the Validation of Optical Coherence Tomography in Differentiation of Prostate Cancer

      Customized Tool for the Validation of Optical Coherence Tomography in Differentiation of Prostate Cancer
      Objective: To design and demonstrate a customized tool to generate histologic sections of the prostate that directly correlate with needle-based optical coherence tomography pullback measurements. Materials and Methods: A customized tool was created to hold the prostatectomy specimens during optical coherence tomography measurements and formalin fixation. Using the tool, the prostate could be sliced into slices of 4 mm thickness through the optical coherence tomography measurement trajectory. In this way ...
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    12. Validation of quantitative attenuation and backscattering coefficient measurements by optical coherence tomography in the concentration-dependent and multiple scattering regime

      Validation of quantitative attenuation and backscattering coefficient measurements by optical coherence tomography in the concentration-dependent and multiple scattering regime
      Optical coherence tomography (OCT) has the potential to quantitatively measure optical properties of tissue such as the attenuation coefficient and backscattering coefficient. However, to obtain reliable values for strong scattering tissues, accurate consideration of the effects of multiple scattering and the nonlinear relation between the scattering coefficient and scatterer concentration (concentration-dependent scattering) is required. We present a comprehensive model for the OCT signal in which we quantitatively account for both ...
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    13. Percutaneous Needle Based Optical Coherence Tomography for the Differentiation of Renal Masses: a Pilot Cohort

      Percutaneous Needle Based Optical Coherence Tomography for the Differentiation of Renal Masses: a Pilot Cohort
      To view the full text, please login as a subscribed user or purchase a subscription . Click here to view the full text on ScienceDirect. The aim of this study is to determine the ability of percutaneous needle based Optical Coherence Tomography (OCT) to differentiate renal masses, by using the attenuation coefficient (OCT, mm-1) as a quantitative measure. Percutaneous needle based OCT of the kidney was performed in patients presenting with ...
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    14. Learning curve and interobserver variance in quantification of the optical coherence tomography attenuation coefficient

      Learning curve and interobserver variance in quantification of the optical coherence tomography attenuation coefficient
      The learning curve and interobserver variance of attenuation coefficient ( OCT ) determination from optical coherence tomography (OCT) images were quantified. The OCT of normal and diseased vulvar tissues was determined at five time points by three novice students and three OCT experts who reached consensus for reference. Students received feedback between time points. Eventually, variance in OCT was smaller in images of diseased tissue than in images of normal vulvar tissue ...
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    15. Assesment of apoptosis induced changes in scattering using optical coherence tomography

      Assesment of apoptosis induced changes in scattering using optical coherence tomography
      The aim of this study is to identify changes in scattering with optical coherence tomography (OCT) and relate these measurements with mitochondrial changes during the initiation of apoptosis. Human retinal pigment epithelial cells were cultured and apoptosis was induced using 10% alcohol. Using the attenuation coefficient and backscattering, changes were measured during cell death in a cell-pellet and monolayer respectively. To confirm apoptosis, fluorescent activated cell sorting was used. Mitochondrial ...
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  2. About Ton G. van Leeuwen

    Ton G. van Leeuwen

    Ton G. van Leeuwen studied physics at the University of Amsterdam and received his Ph.D. degree in 1993 from the Laboratory of Experimental Cardiology, University of Utrecht, The Netherlands. Currently, he is head of the department of Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, and Professor at the Biomedical Photonic Imaging group, University of Twente. His current research interests include the clinical application of biomedical optics.

  3. Quotes

    1. OCT is the ‘work horse’ of the biomedical photonics research field ...“Integrating the components in photonics chips will further increase both the technical and the clinical capabilities of OCT. Furthermore, PIC-based OCT will not only make the current applications cheaper but also broaden its application scope.
      In AMC and LioniX International partner on development of OCT modules