scholarly journals Reconstruction of the Human Heart Functional Structure Based On a Few-Channel Magnetocardiogram

2018 ◽  
Vol 13 (2) ◽  
pp. 392-401
Author(s):  
M.N. Ustinin ◽  
Yu.V. Maslennikov ◽  
S.D. Rykunov ◽  
V.A. Krymov
Keyword(s):  
Human Heart ◽  
Functional Structure ◽  
Magnetic Shielding ◽  
Problem Solution ◽  
Magnetic Dipoles ◽  
Inverse Problem Solution ◽  
Spectral Components ◽  
Measured Information ◽  
The Fourier Transform ◽  
Usual Laboratory

The new method of magnetocardiography data analysis is proposed. The method is based on the Fourier transform of prolonged time series and on the massive inverse problem solution for all spectral components. Magnetocardiograms (MCG) were registered in the plane above the subject’s chest in the nodes of the “rectangular” (6×6) grid with the step 40 mm at usual laboratory conditions without any additional magnetic shielding. The 9-channel MCG-system “MAG-SCAN-09” with dc-SQUID-based axial second order gradiometers was used. The MCG-recording was performed in four positions of investigated subjects under the instrument to get all 36 MCGs. For each of four positions of the MCG-recording the partial functional tomogram was calculated, which is the spatial distribution of elementary magnetic dipoles, observed in this position. The complete functional tomogram of the thorax was obtained by the summation of four partial functional tomograms, containing the data about the same object, observed from various positions. Filtering and contrasting of the complete functional tomogram made it possible to extract the 3D-object, representing the functional structure of the heart. The method was used for five subjects and provided consistent results. It is possible to use this method in cardiography, because the functional tomogram contains all measured information about individual heart.

scholarly journals Reconstruction of the Human Hand Functional Structure Based On a Magnetomyogram

2018 ◽  
Vol 13 (2) ◽  
pp. 480-489 ◽  
Author(s):  
M.N. Ustinin ◽  
S.D. Rykunov ◽  
M.A. Polikarpov ◽  
A.Y. Yurenya ◽  
S.P. Naurzakov ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Human Muscle ◽  
Functional Structure ◽  
Human Hand ◽  
Muscle System ◽  
Spectral Components ◽  
Clenched Hand ◽  
Massive Solution ◽  
The Subject ◽  
The Fourier Transform

The new method of magnetomyography data analysis is proposed. The method is based on the Fourier transform of prolonged time series and on the massive solution of the inverse problem for all spectral components. For the method testing the following experiment was proposed. The subject clenched and relaxed the hand for five minutes, holding the handle, fixed on the table. Magnetomyograms were registered near the hand using the 7-channel SQUID-magnetometer based on the axial second-order gradiometers. The subject and experimental setup were placed inside a thick-walled aluminum camera, designed for shielding from an alternating electromagnetic field. No shielding from static magnetic field was used. Magnetomyograms with amplitude 20 picoTesla were registered in broad frequency band (up to 500 Hz), signal to noise ratio was more than 20. After filtering and extracting of clench/relax periods two synthetic 135 seconds myograms were formed. The multichannel spectra were calculated, and the functional tomograms were estimated. In case of the relaxed hand, no significant object was reconstructed. In case of the clenched hand, the 3D-object was extracted, representing the functional structure of the muscles, tensed in this experiment. The method can be used for diagnostics and study of the human muscle system.

scholarly journals MULTI-CHANNEL MAGNETOCARDIOGRAPH: CONTROL AND SOFTWARE

2014 ◽  
pp. 120-124
Author(s):  
Igor Voytovych ◽  
Myhailo Primin ◽  
Valery Vasyliev ◽  
Pavlo Sutkovyy ◽  
Mykola Budnyk ◽  
...  
Keyword(s):  
Human Heart ◽  
Electric Activity ◽  
Computer Processing ◽  
Problem Solution ◽  
Electronic Unit ◽  
Technology Center ◽  
Inverse Problem Solution ◽  
Virtual Device ◽  
On Line ◽  
Processing Software

Purpose of the work was to present algorithms and software developed for working with multi-channel magneto-cardiograph. Such software is intended for control of operation and computer processing of magnetocardiographic (MCG) data obtained from the human heart. Magnetocardiograph is controlled as “virtual device” from PC mouse/keyboard, so as manually from electronic unit and all that through the control microprocessors embedded into hardware units. Software processing is performed both in on-line mode during process of data acquisition and in off-line manner during post-processing. Software allows preliminary processing, reconstruction and analysis of magnetic maps, and also inverse problem solution. Package is intended both for scientific studying of the heart electric activity and studying of MCG informative indexes for clinical diagnostic of cardiology diseases. Above software is planned to use at Strazhesko Institute of Cardiology (Kyiv) within framework of project supported by Science and Technology Center in Ukraine (STCU).

scholarly journals Photon Phase Shift Imaging Research on Frequency Domain Diffuse Optic Tomography

2021 ◽  
Author(s):  
huseyin ozgur kazanci
Keyword(s):  
Phase Shift ◽  
Frequency Domain ◽  
Laser Intensity ◽  
Model Problem ◽  
Modulation Frequency ◽  
Forward Model ◽  
Problem Solution ◽  
Inverse Problem Solution ◽  
Phase Data ◽  
Cartesian Coordinate

Abstract Diffuse optic imaging is an important biomedical optic research tool. Diffuse optic tomography (DOT) modality needs progressive philosophical approaches for scientific contribution. Technological developments and philosophical approaches should both go forward. Phase-shift based frequency domain (FD) diffuse optical tomography (FDDOT) method was well established in the literature. The instruments were tested for brain neurofunctional imaging. A mixture of AC laser intensity and phase data were used at these works. According to those works; deep volume resolution was improved by only using phase data. Because phase data is only related to the photon mean free path in imaging tissue media. Besides this advantage, laser intensity data is also affected by noisy background light and electrical artifacts. Another most important advantage of only using phase data can be explained as time-resolved temporal change can be directly related to phase shift of modulated frequency source. At this work, the frequency domain (FD) DOT imaging method which uses phase shift data were used for simulation phantom. Laser source-driven forward model problem weight matrix simulation data was given to the simple pseudo-inverse-based inverse problem solution algorithm for one inclusion example. The inclusion image was reconstructed and demonstrated successfully. Forward model problem weight functions inside the tissue simulation media were calculated and used based on the phase shifts at the same core modulation frequency. 100 MHz modulation frequency was selected due to its FDDOT standard. 13 sources and 13 detectors were placed on the back-reflected imaging surface. 40 x, y, z cartesian coordinate grid elements were used in the image reconstruction algorithm. Photon absorption coefficient: ma = 0.1 cm-1, and scattering coefficient: ms = 100 cm-1 values were set for background simulation phantom. One inclusion object was embedded inside the imaging tissue simulation phantom background. x, y, z cartesian coordinate grid sizes were selected for 100 mm for each direction. Photon phase shift fluencies were added to the forward model problem. The forward model problem was built according to the frequency domain photon migration diffusion approximation. Forward model problem photon fluencies were calculated according to the diffusion equation approximation. The simple pseudoinverse mathematical inverse problem solution algorithm was applied to test the results. The embedded inclusion object was reconstructed successfully with the high-resolution image quality. In general, DOT techniques suffer for the low image quality, but in this work, the high-quality image was reconstructed and demonstrated. The philosophical approach has future promising DOT imaging capability. The phase shift version of the FDDOT modality has an important advantage for future purpose.

Inverse problem solution for a laser flash studies of a thin layer coatings

2017 ◽  
Vol 27 (3) ◽  
pp. 698-710 ◽  
Author(s):  
Wit Stryczniewicz ◽  
Janusz Zmywaczyk ◽  
Andrzej Jaroslaw Panas
Keyword(s):  
Inverse Problem ◽  
Heat Conduction ◽  
Thin Layer ◽  
Laser Flash ◽  
Problem Solution ◽  
Flake Graphite ◽  
Estimation Technique ◽  
Content Type ◽  
Inverse Problem Solution ◽  
Layer Sample

Purpose The paper aims to discuss the inverse heat conduction methodology in solution of a certain parameter identification problem. The problem itself concerns determination of the thermophysical properties of a thin layer coating by applying the laser flash apparatus. Design/methodology/approach The modelled laser flash diffusivity data from the three-layer sample investigation are used as input for the following parameter estimation procedure. Assuming known middle layer, i.e. substrate properties, the thermal diffusivity (TD) of the side layers’ material is determined. The estimation technique utilises the finite element method for numerical solution of the direct, 2D axisymmetric heat conduction problem. Findings The paper presents methodology developed for a three-layer sample studies and results of the estimation technique testing and evaluation based on simulated data. The multi-parametrical identification procedure results in identification of the out of plane thin layer material diffusivity from the inverse problem solution. Research limitations/implications The presentation itself is limited to numerical simulation data, but it should be underlined that the flake graphite thermophysical parameters have been utilised in numerical tests. Practical implications The developed methodology is planned to be applied in detailed experimental studies of flake graphite. Originality/value In the course of a present study, a methodology of the thin-coating layer TD determination was developed. In spite of the fact that it has been developed for the graphite coating investigation, it was planned to be universal in application to any thin–thick composite structure study.

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