1. Articles from Patrick Steiner

    1-7 of 7
    1. Automatic assessment of time-resolved OCT images for selective retina therapy

      Automatic assessment of time-resolved OCT images for selective retina therapy

      Purpose In recent years, selective retina laser treatment (SRT), a sub-threshold therapy method, avoids widespread damage to all retinal layers by targeting only a few. While these methods facilitate faster healing, their lack of visual feedback during treatment represents a considerable shortcoming as induced lesions remain invisible with conventional imaging and make clinical use challenging. To overcome this, we present a new strategy to provide location-specific and contact-free automatic feedback of SRT laser applications. Methods We leverage time-resolved optical coherence tomography (OCT) to provide informative feedback to clinicians on outcomes of location-specific treatment. By coupling an OCT system to SRT ...

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    2. Time-Resolved Ultra–High Resolution Optical Coherence Tomography for Real-Time Monitoring of Selective Retina Therapy

      Time-Resolved Ultra–High Resolution Optical Coherence Tomography for Real-Time Monitoring of Selective Retina Therapy

      Purpose : Selective retina therapy (SRT) is a novel treatment for retinal pathologies, solely targeting the RPE. During SRT, the detection of an immediate tissue reaction is challenging, as tissue effects remain limited to intracellular RPE photodisruption. Time-resolved ultra-high axial resolution optical coherence tomography (OCT) is thus evaluated for the monitoring of dynamic optical changes at and around the RPE during SRT. Methods : An experimental OCT system with an ultra-high axial resolution of 1.78 μm was combined with an SRT system and time-resolved OCT M-scans of the target area were recorded from four patients undergoing SRT. Optical coherence tomography scans ...

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    3. Automatic estimation of noise parameters in Fourier-domain optical coherence tomography cross sectional images using statistical information

      Automatic estimation of noise parameters in Fourier-domain optical coherence tomography cross sectional images using statistical information

      Steiner, Patrick; Kowal, Jens H; Pova?ay, Boris; Meier, Christoph; Sznitman, We present an application and sample independent method for the automatic discrimination of noise and signal in optical coherence tomography Bscans. The proposed algorithm models the observed noise probabilistically and allows for a dynamic determination of image noise parameters and the choice of appropriate image rendering parameters. This overcomes the observer variability and the need for a priori information about the content of sample images, both of which are challenging to estimate systematically with current systems. As such, our approach has the advantage of automatically determining crucial parameters for ...

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    4. Assessment of ultra-high resolution optical coherence tomography for monitoring tissue effects caused by laser photocoagulation of ex-vivo porcine retina

      Assessment of ultra-high resolution optical coherence tomography for monitoring tissue effects caused by laser photocoagulation of ex-vivo porcine retina

      Retinal laser photocoagulation is an established and successful treatment for a variety of retinal diseases. While being a valuable treatment modality, laser photocoagulation shows the drawback of employing high energy lasers which are capable of physically destroying the neural retina. For reliable therapy, it is therefore crucial to closely monitor the therapy effects caused in the retinal tissue. A depth resolved representation of optical tissue properties as provided by optical coherence tomography may provide valuable information about the treatment effects in the retinal layers if recorded simultaneously to laser coagulation. Therefore, in this work, the use of ultra-high resolution optical ...

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    5. Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept

      Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept

      Purpose: External beam radiation therapy is currently considered the most common treatment modality for intraocular tumors. Localization of the tumor and efficient compensation of tumor misalignment with respect to the radiation beam are crucial. According to the state of the art procedure, localization of the target volume is indirectly performed by the invasive surgical implantation of radiopaque clips or is limited to positioning the head using stereoscopic radiographies. This work represents a proof-of-concept for direct and noninvasive tumor referencing based on anterior eye topography acquired using optical coherence tomography (OCT). Methods: A prototype of a head-mounted device has been developed ...

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    6. Design and realization of a spectroscopic optical coherence tomography system for medical applications

      Design and realization of a spectroscopic optical coherence tomography system for medical applications

      In this manuscript, we present the design and realization of a Fourier-Domain Spectroscopic-OCT system with a simple spectrometer, based on off-the-shelf parts and a low-cost, state-of-the-art broadband S-LED light source with three spectrally shifted S-LED modules. Depth resolved spectral absorption measurements in the wavelength range from 750 nm to 850 nm are demonstrated using an expansion of OCT called spectroscopic OCT (SOCT). The realized setup was tested and evaluated towards its ability to measure physical parameters such as blood oxygen saturation quantitatively in vivo. Different sample configurations including multilayer setups and scattering layers were used. Additionally, we present the theoretical ...

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    7. Influence and compensation of autocorrelation terms in depth-resolved spectroscopic Fourier-domain optical coherence tomography

      Influence and compensation of autocorrelation terms in depth-resolved spectroscopic Fourier-domain optical coherence tomography
      We demonstrate depth-resolved spectral absorption measurements in the wavelength range from 750 to 850 nm using a broadband light source consisting of three spectrally shifted superluminescent light-emitting diode modules and a low-cost spectrometer-based Fourier-domain optical coherence tomography system. We present the theoretical model and experimental verification of interferences between autocorrelation terms and the signal carrying cross-correlation terms, strongly affecting the absorption measurements. A simple background subtraction, minimizing the artifacts caused by the interferences of autocorrelation and cross-correlation terms, is presented.
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    1-7 of 7
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  2. Topics in the News

    1. (7 articles) Patrick Steiner
    2. (6 articles) University of Bern
    3. (5 articles) Christoph Meier
    4. (3 articles) Jens H. Kowal
    5. (3 articles) Sebastian Wolf
    6. (2 articles) Bern University of Applied Sciences
    7. (2 articles) Volker M. Koch
    8. (2 articles) Boris Považay
    9. (1 articles) University of Lübeck
    10. (1 articles) Bern University Hospital
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    Influence and compensation of autocorrelation terms in depth-resolved spectroscopic Fourier-domain optical coherence tomography Design and realization of a spectroscopic optical coherence tomography system for medical applications Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept Assessment of ultra-high resolution optical coherence tomography for monitoring tissue effects caused by laser photocoagulation of ex-vivo porcine retina Automatic estimation of noise parameters in Fourier-domain optical coherence tomography cross sectional images using statistical information Time-Resolved Ultra–High Resolution Optical Coherence Tomography for Real-Time Monitoring of Selective Retina Therapy Automatic assessment of time-resolved OCT images for selective retina therapy Retinal Vascular Features in Ocular Blunt Trauma by Optical Coherence Tomography Angiography Non-invasive imaging of a choroidal macrovessel Correlation between optical coherence tomography, multifocal electroretinogram findings and visual acuity in diabetic macular edema Digital Wavefront Sensing Ciliary body length revisited by anterior segment optical coherence tomography: implications for safe access to the pars plana for intravitreal injections