Optical signatures of small, deeply embedded, tumor-like inclusionsin tissue-like turbid media based on a random-walk theory of photonmigration

摘要

Optical methods for detecting tumors in tissue are desirable inpart because optical photons are non-ionizing. The highly scatteringnature of tissue makes traditional, and even time-gated, optical imagingimpractical for sites deeper than a few millimeters. Scattering intissue causes dispersion in the path lengths of traversing photons whichblurs images. With a theoretical description of path length dispersion,however, the perturbation caused by a localized anomaly may beidentified from time-resolved intensity data. Random walk theory hasbeen used to show a quantitative, closed-form relationship between theperturbation and the inclusion size and scattering properties relativeto the background. Using Monte Carlo data, the authors show a method foranalyzing the sensitivity of the relationship to signatures of small,deeply embedded, abnormally scattering inclusions