Spectrophotometric examination of tissue of small dimension

Abstract

A system for examination of a relatively small volume of biological tissue of interest using visible or infra-red radiation includes a spectrophotometer, an optical medium of a relatively large volume having selectable scattering and absorptive properties, and a processor adapted to determine a physiological property of the examined tissue. The spectrophotometer includes a light source for introducing radiation at an optical input port, a detector for detecting radiation that has migrated through a path from the input port to an optical detection port, and a processor for evaluating changes between the introduced and the detected radiation. The biological tissue of interest is positioned into the photon migration path inside the optical medium to create a tissue-medium optical path. The optical medium is adapted to limit substantially escape of photons from the tissue. The processor determines a physiological property of the tissue based on the detected optical property of the tissue-medium optical path and the scattering or absorptive properties of the selected optical medium. Alternatively, the system can match the optical properties of the medium to the optical properties of the tissue. The spectrophotometer is a continuous wave spectrophotometer, a phase modulation spectrophotometer or a time-resolved spectrophotometer.