1. Institute of Applied Physics

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    1. Mentioned In 141 Articles

    2. Spectral domain optical coherence tomography based imaging biomarkers for diabetic retinopathy

      Spectral domain optical coherence tomography based imaging biomarkers for diabetic retinopathy
      To evaluate the role of central subfield thickness (CST), cube average thickness (CAT), and cube volume (CV) as imaging biomarkers for severity of diabetic retinopathy within the ETDRS-based grades of retinopathy using spectral domain optical coherence tomography (SD-OCT). This study aims to evaluate the role of macular CST, CAT, and CV on SD-OCT as imaging biomarkers for severity of DR. One hundred ninety-four consecutive cases of type 2 diabetes mellitus ...
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    3. Full-Field Optical Coherence Tomography Based on a MII-4 Microprofilometer Using Microlenses with Air Immersion

      Full-Field Optical Coherence Tomography Based on a MII-4 Microprofilometer Using Microlenses with Air Immersion
      A modernized Linnik microprofilometer (MII-4) allowing the performing of tomographic investigation of transparent and relatively turbid media by the methods of low-coherence interferometry has been presented. The design of the reference channel of the standard MII-4 has been revised. A dynamic adjustment of the reference arm length has been added to compensate for the effect of divergence between focal and coherent volumes, as well as spherical aberration that occurs when ...
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    4. Elimination of Artifacts Caused by the Nonidentity of Parallel Signal-Reception Channels in Spectral Domain Optical Coherence Tomography

      Elimination of Artifacts Caused by the Nonidentity of Parallel Signal-Reception Channels in Spectral Domain Optical Coherence Tomography
      We study the causes of artifact appearance in the images obtained by the method of spectral domain optical coherence tomography with parallel reception of the optical-spectrum components, which are manifested in repetition and overlay of the structural elements of the images of the studied medium with a shift in depth. It is shown that nonidentity of the transfer characteristics of the channels of the multichannel photoreceiving elements is one of ...
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    5. Compensation for the Influence of Fluctuations in the Distance to the Object During Noncontact Probing in Spectral Domain Optical Coherence Tomography

      Compensation for the Influence of Fluctuations in the Distance to the Object During Noncontact Probing in Spectral Domain Optical Coherence Tomography
      We propose and experimentally test a numerical method for correction of the influence of fluctuations in the distance to objects during noncontact probing in optical coherence tomography. The method is based on the analysis of phase shifts of the neighboring scans, which are due to microscale displacements, and further compensation for these displacements by using phasefrequency correction in the spectral domain. Unlike the known correlation methods, the proposed method does ...
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    6. Analysis of low-scattering regions in optical coherence tomography

      Analysis of low-scattering regions in optical coherence tomography
      Analysis of semi-transparent low scattering biological structures in optical coherence tomography (OCT) has been actively pursued in the context of lymphatic imaging, with most approaches relying on the relative absence of signal as a means of detection. Here we present an alternate methodology based on spatial speckle statistics, utilizing the similarity of a distribution of given voxel intensities to the power distribution function of pure noise, to visualize the low-scattering ...
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    7. Optical coefficients as tools for increasing the optical coherence tomography contrast for normal brain visualization and glioblastoma detection

      Optical coefficients as tools for increasing the optical coherence tomography contrast for normal brain visualization and glioblastoma detection
      The methods used for digital processing of optical coherence tomography (OCT) and crosspolarization (CP) OCT images are focused on improving the contrast ratio of native structural OCT images. Such advances are particularly important for the intraoperative detection of glioma margins where the visual assessment of OCT images can be difficult and lead to errors. The aim of the study was to investigate the application of optical coefficients obtained from CP ...
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    8. Improving the Transverse Resolution of Optical Coherence Tomography with a Finite Impulse Response Filter and a Series of Numerically Refocused Images

      Improving the Transverse Resolution of Optical Coherence Tomography with a Finite Impulse Response Filter and a Series of Numerically Refocused Images
      Among the numerous methods for improving the informative value of the optical coherence tomography (OCT), a special place is taken by the methods for increasing the spatial resolution of the resulting images. Increasing the resolution allows one to identify more clinically significant structures in OCT images and thus improve the diagnostic value of OCT. Since the transverse resolution of OCT images is determined by the physical principles different from those ...
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    9. An Experimentally Trained Noise Filtration Method of Optical Coherence Tomography Signals

      An Experimentally Trained Noise Filtration Method of Optical Coherence Tomography Signals
      A method for wavelet filtration procedure training for optical coherence tomography (OCT) images using the experimental measurements of test objects that were constructed by means of water solutions of monodisperse nanoparticles and several microscopic inclusions has been described in the present paper. The choice of test-object parameters (concentration of water solution, size of nanoparticles, and shape, dimensions, and mutual position of inclusions) has allowed the modeling of various working conditions ...
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    10. En-face optical coherence tomography/fluorescence endomicroscopy for minimally invasive imaging using a robotic scanner

      En-face optical coherence tomography/fluorescence endomicroscopy for minimally invasive imaging using a robotic scanner
      We report a compact rigid instrument capable of delivering en-face optical coherence tomography (OCT) images alongside (epi)-fluorescence endomicroscopy (FEM) images by means of a robotic scanning device. Two working imaging channels are included: one for a one-dimensional scanning, forward-viewing OCT probe and another for a fiber bundle used for the FEM system. The robotic scanning system provides the second axis of scanning for the OCT channel while allowing the ...
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    11. Application of the Method of Multiple Mutual Synchronization of Parallel Computational Threads in Spectral-Domain Optical Coherent Tomography Systems

      Application of the Method of Multiple Mutual Synchronization of Parallel Computational Threads in Spectral-Domain Optical Coherent Tomography Systems
      A method for multiple mutual synchronization of parallel computational threads, which is used in spectral-domain optical coherence tomography systems, is described. Due to the effective distribution of the computational load in the central processor of the control computer, the method made it possible to perform procedures for calculating tomographic slices of the subsurface tissues of a living organism in real time. The application of this method made it possible to ...
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    12. Semi-analytical full-wave model for simulations of scans in optical coherence tomography with accounting for beam focusing and the motion of scatterers

      Semi-analytical full-wave model for simulations of scans in optical coherence tomography with accounting for beam focusing and the motion of scatterers
      A full-wave model for simulating images in spectral-domain optical coherence tomography (OCT) with rigorous accounting for the beam-focusing effects is developed. Due to the analytical description of beam focusing, the model is computationally rather efficient. It also uses a rigorous numerical summation of the contributions of the localized sub-resolution scatterers, accounting for variations in the phase-amplitude parameters of the incident and backscattered optical waves, with a subsequent integration of the ...
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    13. Cross-polarization optical coherence tomography for brain tumor imaging

      Cross-polarization optical coherence tomography for brain tumor imaging
      This paper considers valuable visual assessment criteria for distinguishing between tumorous and non-tumorous tissues, intraoperatively, using cross-polarization OCT (CP OCT) OCT with a functional extension, that enables detection of the polarization properties of the tissues in addition to their conventional light scattering. Materials and methods. The study was performed on 176 ex vivo human specimens obtained from 30 glioma patients. To measure the degree to which the typical parameters of ...
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    14. Time-related ex vivo changes in the optical properties of normal brain tissues

      Time-related ex vivo changes in the optical properties of normal brain tissues
      The aim of the study was to observe time-related changes in the optical properties of normal brain tissues as measured using cross-polarization optical coherence tomography (CP OCT). 32 ex vivo tissue samples from 16 animals (rats) were monitored under different external conditions, over a period of 1 hour after excision, to measure time-related optical changes. It was found that the optical properties of white matter were quite stable over the ...
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    15. Optical coherence angiography without motion correction preprocessing

      Optical coherence angiography without motion correction preprocessing
      The method for vessel visualization from optical coherence tomography (OCT) data is presented. The method is based on high-frequency filtration of the normalized absolute values of the scattered field measured with OCT. It is shown that in contrast with optical coherence angiography based on the processing of complex values of a scattered field, the proposed processing does not require motion correction preprocessing while providing resulting angiographic images of comparable quality.
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    16. Quantitative nontumorous and tumorous human brain tissue assessment using microstructural co- and cross-polarized optical coherence tomography

      Quantitative nontumorous and tumorous human brain tissue assessment using microstructural co- and cross-polarized optical coherence tomography
      Optical coherence tomography (OCT) is a promising method for detecting cancer margins during tumor resection. This study focused on differentiating tumorous from nontumorous tissues in human brain tissues using cross-polarization OCT (CP OCT). The study was performed on fresh ex vivo human brain tissues from 30 patients with high- and low-grade gliomas. Different tissue types that neurosurgeons should clearly distinguish during surgery, such as the cortex, white matter, necrosis and ...
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  2. About Institute of Applied Physics

    Institute of Applied Physics

    Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS) was created by a Decree of the Soviet Government on July 28, 1976. Annually the IAP RAS performs about 350 scientific projects, funded by federal special programs, academic, industry, international and other programs and projects. Among the most prominent achievements of the Institute of Applied Physics RAS are the invention of gyrotrons and gyroklystrons and their upgrading to a high technical level, the development of effective methods to convert and transport powerful electromagnetic radiation, the elaboration of physical principles for excitation and reception of low-frequency sound fields in the ocean and the creation of hardware for hydroacoustics and long-term acoustical monitoring in the ocean, complexes for research of noise radiation characteristics of moving objects, the development of high-rate growth and precision processing of water-soluble crystals, developmet of optical coherent tomography to image biotissue structures and designing an optical tomograph for medical diagnostics of human internal organs  See IAP RAS OCT link HERE.