chapter  29
22 Pages

Elastic-Scattering Spectroscopy and Diffuse Reflectance

Wavelength-dependent spectral measurements of elastically scattered light from tissue, performed in a manner that is sensitive to scattering and absorption properties, may be used to detect and diagnose tissue pathologies. Many tissue pathologies, including a majority of cancers, exhibit significant architectural changes at the cellular and subcellular level. In making a diagnosis, pathologists determine some of these architectural changes by examining surgically removed samples called biopsies. Microscopic assessment, often referred to as histopathology, is performed on the biopsy samples to determine cell and tissue architecture, including the sizes and shapes of cells, the ratio of nuclear to cellular volume, the form of the bilipid membrane, cell clustering patterns, etc. The properties of light elastically scattered in tissue also depend on architectural features. For example, the size of the structures in tissue responsible for the scattering of light determines how much more strongly a short wavelength, e.g., blue light, is scattered than a long wavelength, e.g., red light.