Patent ID: 6263221
Filing Date: 2001-07-17
Classification: A61B,G01N

Abstract:
An in vivo spectroscopic method for examining biological tissue, comprising:positioning an input port at a selected location relative to the biological tissue;positioning a detection port at another location spaced at a selected distance of several centimeters from said input port;generating a first carrier waveform at a selected frequency on the order of 10.sup.8 Hz;introducing into the tissue at said input port electromagnetic radiation of a selected wavelength modulated by said carrier waveform, said wavelength being sensitive to concentration of said absorptive pigment present in the tissue;detecting at said detection port the radiation that has migrated over migration paths in a portion of the tissue from said input port, said portion of the tissue depending on said locations of said input and detection ports;comparing the detected radiation with the introduced radiation and measuring therefrom a phase shift (.theta.) of said detected radiation;providing a scattering of said portion of the tissue;using a recursive procedure to calculate a value of the absorption coefficient, at said wavelength, using the following equation: ##EQU14##andexamining said tissue portion by using said calculated value of the absorption coefficient.