Method of preparing calibration curve for quantitative analysis of in-vivo component, and quantitative analyzer using the calibration curve

• US 7,809,416 B2
• Filed: 08/25/2005
• Issued: 10/05/2010
• Est. Priority Date: 08/25/2004
• Status: Expired due to Fees

• Current Assignee: PHC Holdings Corporation
• Original Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Inventors: Ota, Tomohiro, Hirata, Katsuhiro, Maruo, Katsuhiko
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US11/210,855
• Publication Number:
  US 20060063987A1
• Time in Patent Office: 1,867 Days
• Field of Search: 600309-344, 382/115
• US Class Current: 600/316
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

A method of non-invasively determining a concentration of an in-vivo component such as blood sugar level (glucose) of a subject is provided. An absorption spectrum of the subject is measured by use of near-infrared light. The concentration of the in-vivo component is determined by use of the absorption spectrum of the subject and a calibration curve. The calibration curve is prepared by determining a plurality of difference absorption spectra that are differences between a plurality of near-infrared absorption spectra of a living body and a reference absorption spectrum selected from the near-infrared absorption spectra, determining a plurality of synthetic absorption spectra, which are obtained by synthesizing each of the difference absorption spectra with a previously measured reference absorption spectrum of the subject, and performing a multivariate analysis with use of the obtained synthetic absorption spectra.

Claims

1. 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.

2. The method as set forth in claim 1, wherein said in-vivo component is glucose.

3. The method as set forth in claim 1, wherein said light propagation simulation is a Monte Carlo simulation.