1. Maciej Wojtkowski

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    1. Mentioned In 114 Articles

    2. In vivo volumetric imaging by crosstalk-free full-field OCT

      In vivo volumetric imaging by crosstalk-free full-field OCT
      Cellular resolution imaging of biological structures has always been a challenge due to strong scattering that limits the achievable transverse resolution or imaging penetration depth. Recently, a major advancement toward high-resolution and volumetric imaging was achieved by implementing a parallel detection (i.e., full field) into Fourier-domain optical coherence tomography. The drawback of using parallel detection is that scattered light can travel laterally and get mapped improperly at a camera ...
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    3. Air-Puff-Induced Dynamics of Ocular Components Measured with Optical Biometry

      Air-Puff-Induced Dynamics of Ocular Components Measured with Optical Biometry
      Purpose : To analyze the dynamics of all optical components of the eye and the behavior of the eyeball under air-puff conditions in vivo. To determine the impact of the intraocular pressure (IOP) on the air-puff-induced deformation of the eye. Methods : Twenty eyes of 20 healthy subjects were included in this study. The dynamics of the ocular components, such as the cornea, the crystalline lens, and the retina, was measured by ...
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    4. Spatiotemporal optical coherence (STOC) manipulation suppresses coherent cross-talk in full-field swept-source optical coherence tomography

      Spatiotemporal optical coherence (STOC) manipulation suppresses coherent cross-talk in full-field swept-source optical coherence tomography
      Full-field swept-source optical coherence tomography (FF-SS-OCT) provides high-resolution depth-resolved images of the sample by parallel Fourier-domain interferometric detection. Although FF-SS-OCT implements high-speed volumetric imaging, it suffers from the cross-talk-generated noise from spatially coherent lasers. This noise reduces the transversal image resolution, which in turn, limits the wide adaptation of FF-SS-OCT for practical and clinical applications. Here, we introduce the novel spatiotemporal optical coherence (STOC) manipulation. In STOC the time-varying inhomogeneous ...
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    5. Non invasive optical cellular imaging in humans

      Non invasive optical cellular imaging in humans
      One of the most appealing and still unsolved problems in biological and medical imaging is the possibility of noninvasive visualization of tissue in vivo with an accuracy of microscopic examination. A major difficulty to solve in biomedical imaging is a degradation of image quality caused by the presence of optical inhomogeneity of tissue. Is there any chance to develop a microscopic method that allows non-invasive observation of cells in living ...
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    6. Enhancing microvasculature maps for Optical Coherence Tomography - Angiography (OCT-A)

      Enhancing microvasculature maps for Optical Coherence Tomography - Angiography (OCT-A)
      OCT-A is becoming more popular in recent years and there is a high demand to improve the quality of angiograms as well as to extract quantitative information. We applied various processing methods for microvasculature enhancement like Hessian-Frangi to a data set obtained with Bessel and Gaussian OCT systems. We used angiogenesis, fractal and multifractal analysis to extract more quantitative information. We applied the processing methods for healthy, stroke, tumor progression ...
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    7. Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air‐puff optical coherence tomography and corneal hysteresis

      Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air‐puff optical coherence tomography and corneal hysteresis
      Application of the air‐puff swept source OCT (SS‐OCT) instrument to determine the influence of viscoelasticity on the relation between overall the air‐puff force and corneal apex displacement of porcine corneas ex vivo is demonstrated. Simultaneous recording of time‐evolution of the tissue displacement and air pulse stimulus allows obtaining valuable information related in part to the mechanical properties of the cornea. A novel approach based on quantitative ...
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    8. Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos

      Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos
      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging ...
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    9. Classification of biological micro-objects using optical coherence tomography

      Classification of biological micro-objects using optical coherence tomography
      We report on the development of a technique for differentiating between biological micro-objects using a rigorous, full-wave model of OCT image formation. We model an existing experimental prototype which uses OCT to interrogate a microfluidic chip containing the blood cells. A full-wave model is required since the technique uses light back-scattered by a scattering substrate, rather than by the cells directly. The light back-scattered by the substrate is perturbed upon ...
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    10. Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos
      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging ...
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    11. Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT

      Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT
      Optical coherence tomography (OCT) has become one of the most successful optical technologies implemented in medicine and clinical practice mostly due to the possibility of non-invasive and non-contact imaging by detecting back-scattered light. OCT has gone through a tremendous development over the past 25 years. From its initial inception in 1991 [Science 254 , 1178 (1991)] it has become an indispensable medical imaging technology in ophthalmology. Also in fields like cardiology ...
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    12. Spectrometer calibration for spectroscopic Fourier domain optical coherence tomography

      Spectrometer calibration for spectroscopic Fourier domain optical coherence tomography
      We propose a simple and robust procedure for Fourier domain optical coherence tomography (FdOCT) that allows to linearize the detected FdOCT spectra to wavenumber domain and, at the same time, to determine the wavelength of light for each point of detected spectrum. We show that in this approach it is possible to use any measurable physical quantity that has linear dependency on wavenumber and can be extracted from spectral fringes ...
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    13. Extended-focus optical coherence microscopy for high-resolution imaging of the murine brain

      Extended-focus optical coherence microscopy for high-resolution imaging of the murine brain
      We propose a new method and optical instrumentation for mouse brain imaging based on extended-focus optical coherence microscopy. This in vivo imaging technique allows the evaluation of the cytoarchitecture at cellular level and the circulation system dynamics in three dimensions. This minimally invasive and non-contact approach is performed without the application of contrasting agents. The optical design achieved a resolution of 2.2 m over a distance of 800 m ...
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    14. Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography

      Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography
      In this paper, we use swept source optical coherence tomography combined with air-puff module (air-puff SS-OCT) to investigate the properties of the cornea. During OCT measurement the cornea was stimulated by short, air pulse, and corneal response was recorded. In this preliminary study, the air-puff SS-OCT instrument was applied to measure behavior of the porcine corneas under varied, well-controlled intraocular pressure conditions. Additionally, the biomechanical response of the corneal tissue ...
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    15. Method and apparatus for imaging of semi-transparent matter

      Method and apparatus for imaging of semi-transparent matter
      The invention relates to a method and apparatus for measuring the spatial and velocity distribution of scattering structures of a sample in semi-transparent matter. The acquired spectral data I(k, t) are transformed in two steps to image data I(z, v). A Doppler shift is imposed on the light to a separate real and mirror images in the v space to suppress the complex ambiguity artifact.
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    16. Coherence properties of fast frequency swept lasers revealed via full electric field reconstruction

      Coherence properties of fast frequency swept lasers revealed via full electric field reconstruction
      A novel, time-resolved interferometric technique is presented allowing the reconstruction of the complex electric field output of a fast frequency swept laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography applications, with a spectral bandwidth of 18 THz. This novel analysis of the complete electric field reveals the modal structure and modal evolution of the ...
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    17. 1-15 of 114 1 2 3 4 5 6 7 8 »
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  2. About Maciej Wojtkowski

    Maciej Wojtkowski

    Maciej Wojtkowski (b.1975) received his MSc and PhD in physics from Nicholas Copernicus University (NCU), Torun, Poland. Presently he has a faculty position of research assistant professor in the Institute of Physics, NCU, Poland. His research interest includes optical coherence tomography and low coherence interferometry applied to biomedical imaging.
    He is active in the field of Optical Coherence Tomography (OCT) and its ophthalmic applications. Dr Wojtkowski has impact on development of Spectral OCT technique. The first SOCT instrument for in vivo retinal imaging was designed and constructed by dr Wojtkowski and his colleagues from the Medical Physics Group at Nicolaus Copernicus University Poland in 2001. Application of Spectral OCT to ophthalmology enabled group from Torun obtaining retinal cross-sectional images with the shortest exposure times and in turn it allowed proving speed and sensitivity advantage of Spectral OCT over standard OCT method. Dr Wojtkowski also contributed in development and construction of three clinical prototype high resolution SOCT instruments which are in use in ophthalmology clinics: in Collegium Medicum in Bydgoszcz, Poland, New England Eye Center, Boston, USA, and UPMC Pittsburgh.

  3. Quotes

    1. For our group at NCU it was more about having an industrial partner, which in the long term could give job opportunities for MSc and PhD students and PhDs from our group one of the conditions of our collaboration was creation by Optopol a R&D office at NCU.
      In Optical Coherence Tomography Used $500M of Federally Funded Research Over The Past Decade: How was it Used, What was Accomplished, and What’s to Come?