Abstract: The present invention discloses methods and apparatus for the quantitation and localization of tissue hypoxia by both time and frequency domain spectroscopy. The present invention provides several alternate embodiments of apparatus by which the saturation of a tissue region may be determined. In the time-resolved embodiment, a simplified system provides data which are directly proportional to the tissue saturation. In the phase modulating embodiments of the present invention, a first embodiment provides phase shift data which may be converted into saturation readings. A second embodiment, separates the real and imaginary portions of the signal and uses these data along with the data gathered from the DC portion of the signal to determine saturation. Methods of determining the hemoglobin concentration/oxygenation of a tissue region are also disclosed.

Abstract: A method and system for examination of a subject positioned between input and detection ports of the spectroscopic system applied to the subject. The systems shown include at least one light source for introducing at one or multiple input ports, electromagnetic non-ionizing radiation of a known time-varying pattern of photon density of a wavelength selected to be scattered and absorbed while migrating in the subject, radiation pattern control means for achieving a directional pattern of emitted resulting radiation that possesses substantial gradient of photon density, at least one detector for detecting the radiation that has migrated in the subject at one or multiple detection ports. The systems also include processing means for processing the detected radiation and creating sets of data, and evaluation means for examining the subject using the data sets. The emitted directional radiation pattern utilizes its gradient of photon density to detect a hidden object while scanning across the examined subject.