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Invited Talks

Frequency Domain Optical Coherence Tomography

Prof. Christoph Meier
Professor of Physics and Optics, Bern University of Applied Sciences

Abstract

In a brief introduction, the principles of optical coherence tomography (OCT) systems are elucidated and their performance and limitations are discussed. Today, OCT applications are normally based on the frequency/Fourier domain method (FD-OCT). The advantages of this technique are explained and some of the recent state of the art applications are presented. A drawback of the FD-OCT method is the bisection of the working distance due to the symmetry property of the Fourier transformation. Different approaches exist to overcome this limitation; the application of a novel algorithm which uses the optical dispersion in the interferometer in order to double the measuring range is presented.

Biography

Christoph Meier obtained a mechanical engineering diploma degree from the School of Engineering, HTL Biel, in 1982. After working three years in industry, mainly in the field of software development, he studied physics at the University of Neuchâtel. Since 1991 he has been working at the Bern University of Applied Science, Division of Microtechnology and Biomedical Engineering, as professor of physics and electrical technology. In 2001, he was elected professor of optics and is now head of the optics group and the “OptoLab”. The main activities of the optics group are in optical sensing, especially in OCT. In 2008, he spent a continuing education semester in the group of W. Drexler, Cardiff.

Vectorial reconstruction of retinal blood flow measured with resonant Doppler FDOCT

Dr. Roland Michaely
Project Engineer, Helbling Technik Bern AG, www.helbling.ch

Abstract

Resonant Doppler Fourier domain optical coherence tomography FDOCT is a functional imaging tool for extracting tissue flow. The method is based on the effect of interference fringe blurring in spectrometer-based FDOCT. The signals of resting structures will be suppressed, whereas the signals of blood flow are enhanced. This allows for an easy extraction of vascularisation structure. Conventional flow velocity analysis extracts only the axial flow component, which strongly depends on the orientation of the vessel with respect to the incident light. We introduce an algorithm to extract the vessel geometry within the 3-D data volume. The algorithm calculates the angular correction according to the local gradients of the vessel orientations. We apply the algorithm on a measured 3-D resonant Doppler dataset.

Biography

Roland Michaely received the M. Sc. degree in microtechnology from the Swiss Federal Institute of Technology (EPFL), Lausanne, in 2003. After his graduation, he joined the Laboratoire d’Optique Biomédicale at the Ecole Polytechnique Fédérale de Lausanne, where he worked toward the Ph.D. degree. At EPFL, he investigated different optical techniques for the in vivo investigation of human tissues: Fringe projection for measurements of skin micro relief, Laser Doppler for blood flow measurements and Fourier Domain Optical Coherence Tomography (FDOCT) for the investigation of skin and retina morphology and physiology. His interests include signal processing and image processing. In 2008, he obtained his Ph.D. degree from EPFL for his work on FDOCT. Since 2007 he has been working as project engineer in the field of Optics & Sensors at Helbling Technik Bern AG.

Ultra High Speed OCT and 3D-teFD

Dr. Boris Považay
School of Optometry and Vision Sciences at Cardiff University in Wales/UK

Abstract

Optical Coherence Tomography (OCT) has been extremely successful as a clinical non-contact imaging modality in ophthalmology for more than a decade. The main improvements were an increase of axial resolution caused by broader bandwidth light sources and a boost in speed due to introduction of frequency domain techniques. In this lecture state-of-the-art OCT technologies like ultra-high speed cameras for speeds above 100MSamples/s, adaptive optics for higher transverse resolution and different wavelengths for deeper penetration into biological tissue are discussed. An attempt to delineate the current limitations of OCT and compare them to clinical demand will be made to conclude with an outlook of possible solutions currently investigated at Cardiff University.

 

Biography

Boris Považay received his Masters degree 1998 at the University of Technology Vienna in "Technical Physics" and continued his work on non-linear laser physics in his PhD studies at the Medical University of Vienna. Combining broadband laser technology with non-linear optical fibres and optical coherence tomography (OCT) lead to advancements like higher resolution and improved penetration. Since 2006 he works as a lecturer at the School of Optometry and Vision Sciences at Cardiff University in Wales/UK in the Biomedical Imaging group lead by Wolfgang Drexler on multiple projects connected to OCT. His research interests lie in the field of novel frequency domain techniques and optical encoding schemes, as well as the incorporation of novel technology to improve clinically relevant imaging parameters, with focus on ophthalmic applications.

 

Volker Koch, 05/2009