Control of optical properties of tissues and blood - recent by daw95820


									        Control of optical properties of tissues and blood - recent achievements
                                        Valery V. Tuchin
                          Department of Optics and Biomedical Physics
                     Research-Educational Institute of Optics and Biophotonics
                                    Saratov State University
                          83 Astrakhanskaya str. Saratov 410012, Russia

This lecture aims to review the recent results on the optical clearing of the naturally turbid
biological tissues and blood using the optical immersion technique, which is well-known in
physical science and applied for reduction of light scattering and undesirable reflections in the
optical system. Basic principles of the technique, its advantages, limitations, and future are
discussed. The refractive index matching concept for enhancement of in-depth light penetration into
tissues and blood is presented on the basis of in vitro and in vivo studies using optical spectroscopy,
polarization and coherence-domain techniques. The index matching of scatterers and ground matter
by means of administration of clearing agents is under discussion. The optical properties of tissues
with basic multiple scattering, which are transformed to a low scattering mode, are analysed. It is
shown that light reflection, transmission, scattering, and polarization can be effectively controlled.
The possibilities of usage of optical immersion method for diagnostic purposes based on contrasting
of abnormalities, on in-depth profiling of tissue and blood, and on monitoring of endogenous and
exogenous matter diffusion within tissue are demonstrated.

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