Polarimetric and spectral imaging approaches for quantitative characterization of inhomogeneous scattering media including biotissues

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Linnanmaa campus, Saalastinsali. Remote connection: https://oulu.zoom.us/j/69614757286

Topic of the dissertation

Polarimetric and spectral imaging approaches for quantitative characterization of inhomogeneous scattering media including biotissues

Doctoral candidate

Master of Science Motahareh Peyvasteh

Faculty and unit

University of Oulu Graduate School, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques (OPEM)

Subject of study

Photonics

Opponent

Ph.D. Iurii N. Zakharov, Harvard Medical School

Custos

Docent Aliaksandr Bykau, University of Oulu

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Polarimetric and spectral imaging approaches for quantitative characterization of biological tissues

Analytical methodologies to analyze optical and polarization properties over time and the obtained results were utilized in biomedical and food science applications. In this thesis, soft biological tissues (pork samples) were selected as a biological tissue due to their similarity to human tissue.

First, the relative spectral changes of absorbance were studied by applying two different custom-built configurations. A Monte Carlo modelling and principal component analysis (PCA) method were applied further to the absorbance dataset to provide thorough studies for a spectroscopic approach. Second, a novel application of Mueller matrix (MM) imaging polarimetry was pioneered to visualize the dynamics of the tissue polarization properties over time with a custom-built Mueller matrix imaging polarimeter (MMIP). Frequency distribution histograms (FDHs) and the changes in the statistical moments of the MM elements were analyzed over time to provide qualitative and quantitative information of the tissue polarization properties. Finally, a new Stokes-polarimetry was introduced to examine optically thin histological sections from optically anisotropic biological tissues with different morphological structures.

In summary, in spectroscopic and imaging polarimetry approaches, prominent changes in optical properties of the examined soft biological tissues were discriminated over time. The obtained results are promising in the development of a novel non-destructive tool for monitoring biological tissues for application in biomedical applications and the food industry. The Stokes polarimetry method can provide a comparative analysis of different polarimetric techniques and prove the diagnostic potential of Stokes correlometry of pathological changes in the orientation phase structure of biological tissues.
Last updated: 22.9.2021