Patent ID: 7139603

Claim:
A spectroscopic system for examination of biological tissue of a subject comprising: at least one source of electromagnetic radiation of a visible or infrared wavelength selected to be scattered and absorbed while migrating in the tissue, said wavelength being sensitive to an exogenous pigment in the examined tissue, said source being optically coupled to at least two input ports; a detection port optically coupled to a detector, said detector connected to a detector circuit; means for positioning a first input port and a second input port relative to selected input locations of a subject; means for selecting for each input port first and second radiation intensities to be introduced to the tissue, said selected radiation intensities defining a null plane in the tissue; means for positioning said detection port relative to a selected detection location of the examined tissue corresponding to said null plane, said input locations and detection location defining a volume of the examined tissue of the subject; said at least one source constructed to emit radiation of said first intensity for introduction into the tissue, at said first input port; said detector constructed to detect, at said detection port, said first radiation that has migrated in the examined tissue; means for storing, in said detector circuit, a first detector signal corresponding to said first detected radiation; said at least one source constructed to emit radiation of said second intensity for introduction into the tissue, at said second input port; said detector constructed to detect, at said detection port, said second radiation that has migrated in the examined tissue; means for storing, in said detector circuit, a second detector signal corresponding to said second detected radiation; and means for subtracting said first detector signal from said second detector signal to obtain processed data corresponding to properties of said tissue volume.