Optical imaging is important in medicine because it provides unique information about human health and an avenue for inexpensive and portable instruments for laboratory, clinical and home use. Within a deep-tissue optical diffusion tomography framework, it becomes possible to determine chemical and molecular information for blood chemistry monitoring and understanding diseases. The research on faster and more accurate deep-tissue imaging is a critical step in facilitating more widespread use of optics in medical research and for treatment. Another important challenge for in vivo optical imaging is access to the regime within a few millimeters of the skin, with application to skin cancer, for example. This research involves the development of a method that describes optical tissue properties on this near-surface length scale and hence provides a basis for imaging. Collectively, this work will be important in applications like the early detection of cancer, intra-operative imaging to ensure all tumor nodules are removed during surgery, and blood chemistry monitoring.
More specifically, various optical diffusion tomography modalities describing scatter and absorption, fluorescence, and fluorescence resonance energy transfer parameters are being developed. The approach avoids a background scattering emulsion, in which the subject is placed, by use of a laser body scan to define the geometry and an unstructured mesh forward model based on the diffusion equation. In this work, a multigrid method coupled to the unstructured mesh permits fast and accurate imaging. In the weakly scattering regime, an imaging method based on the Bethe-Salpeter equation that uses a rigorous field correlation over space and frequency is being developed.
