Persons

The experimental investigation of the laser pulse propagation through the scattering medium has been carried out. A method for determination of the scattering media optical characteristics has been offered. The method is based on measuring the temporal distributions of the intensity of the ultra-short laser pulses using the system of the single photon counts for two values of the thickness of the layer being investigated. The coefficients of absorption and scattering of the model medium have been determined from the experimental results using the offered method.

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In positron emission tomography the number of factors, which distort the tomogram being obtained, exists. One of these factors is the solid angle fraction. Using the numeric simulation the influence of the solid angle fraction on the reconstruction quality of spatial source distribution depending on the object dimensions and the radius of the position-sensitive detector has been studied. The new iterative method for the distortion correction in the reconstructed image has been proposed. The uniform deviation of the reconstructed image from the given one has been calculated depending on the number of the correction algorithm iterations. The results obtained can be used both to improve the quality of tomogram reconstruction for standard algorithms reconstructing the spatial distribution of radiation sources, and to develop a new software for existing tomographs.

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A comparison of the temporal distributions of the laser pulse passing through a homogeneous scattering layer, obtained by the classical and refined diffusion models, with time distributions, simulated by the Monte-Carlo. The inaccuracy of the temporal distributions obtained by means of diffusion models, due to insufficient light scattering has been. It that the refined diffusion model is in better agreement with the simulation results Monte-Carlo method in a wide range of the scattering layer thickness values.

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The propagation of laser pulses through the high scattering medium (HSM) consisting of several homogeneous layers, has been theoretically and experimentally investigated. The analytical solution of the radiation transport equation in the «straight back scattering» approximation for multi-layer HSM has been obtained. The experiments with two-layer HSM have been carried out and their correspondence to the theoretical description has been shown. The obtained results may be used for designing of the bio-medical optical tomographs.

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A new method of using a diffusion model of the radiative transfer to describe the temporal distributions laser pulse passed through the weak scattering layer has been proposed.

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The problem of the light refraction at the object border in optical tomography has been investigated. The modified method of rho-filtration with an auxiliary weight function has been proposed.

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