In this work the version of indirect iterative methods for determination of optical parameters of biological tissues is
presented. This method determines such optical parameters as anisotropy factor (g), absorption coefficient (μa),
scattering coefficient (μs). Both these parameters determine mean free path (ds) which use in simulation of light
propagating trough biological tissue. For light propagation modeling we used weight time-resolved Monte Carlo method
(MCM), time-depended diffusion approximation method (DA), and hybrid method (MCM-DA). Three these methods
can use in different cases. The DA is less accurate and universal technique than MCM but it, in contrast to MCM,
doesn't need large computational burden. Hybrid model has advantages of both methods. We found dependences of
transmitted through biotissue pulse spreading with which optical parameters are determined. In this study we didn't take
into account femtosecond pulse spreading at the expense of refractive index dispersion.
In this work version of inverse Monte Carlo method for determination of optical parameters of biological tissues is presented. This method determine such optical parameters as anisotropy factor (g), absorption coefficient (μa), scattering coefficient (μs) both these coefficients determine mean free path (ds) which use for Monte Carlo simulation method of radiative transfer. These parameters are determined by the step-by-step searching. We have released three methods ofthe optical parameters searching: simple, differential and approximation. Optical parameters are changed by a certain value-step. In the simple searching method step is fixed, in the differential searching method step decreases as we approach to "mistake zone". The differential searching method finds more accurate results for a less time. In the approximation searching method a transfer radiation function (of optical parameter) is approximated by a power polynomial and the optical parameters value is determined from equation. The approximation searching method uses the close value of transfer radiation rate, without the "mistake zone". Using square approximation searching method the optical parameters adipose tissue has determined. The anisotropy factor g is equal 0.876 the scattering and absorption coefficients are equal 19.81 cm-1 and 0.15 cm-1 respectively.
The version of a Monte-Carlo method for simulation of passage of a laser radiation through dispersing media based on use of an integrated evaluation algorithm is described. The algorithm allows one to take into account multi-layer medium, reflection and refraction of light on the boundaries between layers, and also frequency shift at light scattering. The results for skin tissues and polystyrene solution are submitted. The given algorithm is used for modeling processes taking place at two-photon photodynamic therapy.
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