Optical spectroscopy and imaging of tissue in magnetic fields

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Many biomedical applications of light in tissues include simultaneous use of magnetic fields. From fundamental physical principles and experimental observations it is known that strong magnetic fields alter molecular and structural properties of biological materials and tissues. These structural and molecular changes should also result in changes of the optical properties of tissues, fluorophores, and contrast agents.  This proposal requests support for the studies of the influence of magnetic fields on the optical properties of biological tissues. These studies will include assessment of the effects of magnetic fields on the absorptive, scattering, and fluorescent characteristics of tissue, on the depolarizing action of tissue for various polarization states of light, on the fluorescent characteristics of contrast agents and molecular probes, and on the blood flow in humans and in small animal models. I also plan to explore the feasibility of the optical detection of the nuclear magnetic resonance in biological materials and tissues. Since simultaneous optical and MRS/MRI measurements in biomaterials and tissues are now becoming available in the fields up to 20T, it is important to investigate as broad range of magnetic field intensities as possible. The proposed research program is expected to result in a significant progress in biomedical optical techniques. In particular, if the application of the magnetic field improves the penetration depth of the polarized light into tissues and/or increases the polarimetric signal-to-noise ratio, it is likely to lead to a long hoped-for solution of the problem of the non-invasive in-vivo glucose measurements. The proposed studies can also result in the development of fundamentally new magneto-optical methods of tissue characterization, such as the optical MRI and/or MRS. Studies of the optical manifestations of the influence of magnetic fields on tissues and biomaterials will also contribute to a better understanding of the biological effects of magnetic fields, which is very important because of the wide biomedical uses of MRI and MRS.