Pavlo Ivashko

Spectropolarimetry of cancer change of biotissues

This work is directed to the investigation of the scope of the technique of laser polarimetry and polarization spectrometry of oncological changes of the human prostate tissue under the conditions of multiple scattering. It was shown that the third statistic moment in the intensity distribution proved to be the most sensitive to pathological changes in orientation structure. Its value in the intensity distribution of polarization image I (0 - 90) of oncologically changed tissue is 21 times higher if compared with the similar statistic parameter of the intensity distribution of the healthy tissue. The results of studies of size linear dichroism prostate gland, as healthy and affected by malignant tumor at different stages of its development was presented. Significant difference in the values of linear dichroism and its spectral dependence in the spectral range λ = 280 - 840 nm as between research facilities, and between biotissues - healthy (or affected by benign tumors) and cancer patients was shown. These results may have diagnostic value for detection and assessment of the development of cancer.

Diagnostic value spectropolarimetry of blood plasma in patients with breast cancer

The aim was to study the possibility of using polarimetry methods of performance evaluation of blood plasma of patients with breast cancer and spectroscopy method in the diagnosis of breast cancer and determine the criteria for their use of non-invasive screening for problems.

Spectrometry techniques in diagnostics of hereditary breast cancer

The aim was to study the possibility of using polarimetry methods of performance evaluation of blood plasma of patients with breast cancer and spectroscopy method in the diagnosis of breast cancer and determine the criteria for their use of non-invasive screening for problems.

Combining polarimetry and spectropolarimetry techniques in diagnostics of cancer changes in biological tissues

The aim of the study is combining polarimetry and spectropolarimetry techniques for identifying the changes of opticalgeometrical structure in different kinds of biotissues with solid tumours. It is researched that a linear dichroism appears in biotissues (human esophagus, muscle tissue of rats, human prostate tissue, cervical smear) with cancer diseases, magnitude of which depends on the type of the tissue and on the time of cancer process development.

Absorption spectra of adenocarcinoma and squamous cell carcinoma cervical tissues

We studied a methods of assessment of a connective tissue of cervix in terms of specific volume of fibrous component and an optical density of staining of connective tissue fibers in the stroma of squamous cancer and cervix adenocarcinoma. An absorption spectra of blood plasma of the patients suffering from squamous cancer and cervix adenocarcinoma both before the surgery and in postsurgical periods were obtained. Linear dichroism measurements transmittance in polarized light at different orientations of the polarization plane relative to the direction of the dominant orientation in the structure of the sample of biotissues of stroma of squamous cancer and cervix adenocarcinoma were carried. Results of the investigation of the tumor tissues showed that the magnitude of the linear dichroism Δ is insignificant in the researched spectral range λ=280-840 nm and specific regularities in its change observed short-wave ranges.

Spectropolarimetry and fluorescence in biotissue cancer diagnostics

Early detection of malignant transformation is a goal of modern medicine and to this end there is an impressive number of approaches from the scientific field that tries to identify early changes preceding malignant transformation in order to establish a correct diagnosis. This paper aims to combination of polarization and fluorescence techniques for identifying the changes in biotissues of growth and development of experimental solid tumors.

Diffusing low-coherence interferometry of turbid media: an approach to transport parameters evaluation

The features of formation of interferometer output in the case of a broadband light source and random medium as a retro-reflector in the interferometer object arm are considered. It is shown for the large values of the pathlength difference the interferometer output decays exponentially with the decay rate dependent on the transport parameters of a probed random medium. This allows us to determine the transport mean free path of light propagation in the medium. This approach can e applied not only for the strongly scattering media, but also for scattering samples characterized by non-diffusive regime of light propagation.

Simulation of propagation of radiation in epithelial tissues

Different statistical modeling techniques of radiation propagation in epithelial tissue are considered. The two main approaches are: modified classical Monte Carlo method for light propagation in turbid medium and the coherent inverse ray tracing method. Classical Monte Carlo method was modified to take into account polarization of propagated radiation and birefringence which can occur due to tissues commonly found under epithelium. As a supplementary method modified version of classical ray tracing technique is used which takes into account phase of radiation during its propagation in tissue.

Small angle scattering polarization biopsy: a comparative analysis of various skin diseases

An approach to differentiation of the morphological features of normal and pathological human epidermis on the base of statistical analysis of the local polarization states of laser light forward scattered by in-vitro tissue samples is discussed. The eccentricity and the azimuth angle of local polarization ellipses retrieved for various positions of the focused laser beam on the tissue surface, and the coefficient of collimated transmittance are considered as the diagnostic parameters for differentiation. The experimental data obtained with the psoriasis, discoid lupus erythematosus, alopecia, lichen planus, scabies, demodex, and normal skin samples are presented.

Modeling of the polarized light scattering in biotissues by Monte Carlo and photon tracing methods

The basic idea of the used technique is for using stochastic approximation to simulate physical phenomena in the propagation of polarized radiation scattering environment. In the standart modeling only absorbed, missed and reflected photons are calculated, in polarization modeling structural and geometric parameters are noticed. The flowchart contains the basic elements of the standard elements of simulation and calculation with the regard to polarization.