Patent ID: 7809416

Claim:
A method of non-invasively determining a concentration of an in-vivo component of a subject by use of a plurality of difference absorption spectra, wherein the plurality of said difference absorption spectra are defined by a difference between each one of a plurality of first near-infrared absorption spectra of a simulated living body and a first reference absorption spectrum selected from the plurality of the first near-infrared absorption spectra of the simulated living body respectively and wherein the plurality of said difference absorption spectra are predetermined according to a light propagation simulation respectively, which is defined as a method of analyzing a light propagation in the simulated living body, by using optical characteristics including absorption coefficient “μ a ”, scattering coefficient “μ s ”, refraction index “n”, and anisotropic scattering parameter “g” of each epidermis layer, dermis layer and hypodermis layer, said method comprising steps of: measuring a second near-infrared absorption spectra of the subject; determining a second reference absorption spectrum by use of the second near-infrared absorption spectra; synthesizing the plurality of said difference absorption spectra with the second reference absorption spectrum respectively, thereby obtaining a plurality of synthetic absorption spectra; performing a multivariate analysis with use of the plurality of said synthetic absorption spectra to prepare a calibration curve; measuring a third near-infrared absorption spectrum of the subject; and determining the concentration of said in-vivo component of the subject by use of the third near-infrared absorption spectrum of the subject and said calibration curve.