Combined hyperspectral imaging of macroscopic and microscopic samples for tissue optical and structural properties evaluationStergar, Jošt (Avtor) Milanič, Matija (Mentor) Spectroscopyhyperspectral imagingmicroscopybiomedical opticslight scatteringMonte Carlo transporttissue phantomsperitonitisbiomarkersThe goal of the work presented in this thesis was to compare spectroscopic properties of tissues on the macro scale with their underlying microscopic structural properties. Three main objectives that dictate the organization of this thesis were identified. (I) To develop and characterize two hyperspectral imaging systems that can im- age on two different length scales (macro- to mezo-scopic and microscopic imaging systems). (II) To develop and characterize tissue phantoms that can be used for system characterization and as a testing ground for physical models. (III) To use both systems in a clinical study and search for relationships between microscopic tissue structure and their optical properties. Basics of light-tissue interaction are presented in the first chapter. A brief overview of scattering and absorption interaction of light with the tissue is pre- sented through the radiative transfer equation (RTE). A special emphasis is given to the treatment of light scattering according to Mie theory. Since solving RTE is a difficult task, few algorithms that extract optical properties from measured spectra are presented. In the second chapter, development and characterization of the two hyperspectral systems are presented. Mezzo- to macro-scopic imaging system based on imaging spectrograph is presented first, followed by a hyperspectral microscopy system build around a laboratory microscope and a custom developed monochromator. In the third chapter, research regarding tissue phantoms is presented. After presenting the recipe for phantoms, phantom components and their structure are analyzed in depth. Using the knowledge about the phantom properties, both spec- troscopic and structural, effects of their microscopic structure are explored using Mie scattering. Theoretic and macroscopic imaging results are compared to hyper- spectral microscopy. In the fourth chapter, hyperspectral imaging is used in a pre-clinical study of peritonitis in mouse models. Abdominal walls are imaged using the macroscopic system and tissue properties (blood volume fraction, oxygenation, scattering) are evaluated. Based on these properties, biomarkers that show statistical significance in separating diseased and healthy subjects are identified. All the biomarkers are verified and compared to histology. From macroscopic images, blood vasculature structure is extracted and another set of biomarkers is obtained. Based on hyper- spectral microscopic, Fourier-space biomarkers that characterize tissue structure are devised and correlated to macroscopic optical properties. To conclude, two hyperspectral systems were developed and successfully used in a pre-clinical environment. Tissue phantoms were developed and effects of the scat- tering component properties on measurable reflectance spectra were explored. In a pre-clinical study, biomarkers were obtained from both hyperspectral modalities and results compared between both length scales.20212021-10-01 07:15:33Doktorsko delo/naloga131664sl