Living-body component measuring apparatus

• US 8,958,858 B2
• Filed: 03/04/2011
• Issued: 02/17/2015
• Est. Priority Date: 11/26/2009
• Status: Active Grant

• Current Assignee: Yokogawa Electric Corporation
• Original Assignee: Yokogawa Electric Corporation
• Inventors: Tezuka, Shin-ichiro, Hara, Hitoshi
• Primary Examiner(s): Chen, Tse
• Assistant Examiner(s): Liu, Chu Chuan (JJ)
• Application Number:
  US13/041,105
• Publication Number:
  US 20110218412A1
• Time in Patent Office: 1,446 Days
• Field of Search: 600/310, 600/316, 600/322, 600/323, 600/331, 600/336, 600/473, 600/476
• US Class Current: 600/310
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

A living-body component measuring apparatus measures a component of an inner tissue of a living body serving as an object to be measured by emitting laser light having two or more wavelengths from a light source and measuring reflected light of the laser light from the inner tissue of the living body. The living-body component measuring apparatus includes a beam splitter that changes optical paths of a part of the laser light and the reflected light, a reference-light measuring unit that measures, as reference light, the part of the laser light having the optical path changed by the beam splitter, a reflected-light measuring unit that measures the reflected light having the optical path changed by the beam splitter, and an analysis unit that analyzes the inner tissue by measuring a spectrum of the reflected light or the reference light.

Claims

1. A living-body component measuring apparatus that measures a component of an inner tissue of a living body serving as an object to be measured, the living-body component measuring apparatus comprising:

a light source emitting laser light having two or more wavelengths;

a beam splitter that changes optical paths of a part of the laser light emitted from the light source and a reflected light of the laser light from the inner tissue of the living body;

a reference-light measuring unit that measures, as reference light, the part of the laser light emitted from the light source and having the optical path changed by the beam splitter into a first direction;

a reflected-light measuring unit that measures the reflected light reflected by the inner tissue of the living body and having the optical path changed by the beam splitter into a second direction different from the first direction;

an analysis unit that analyzes the inner tissue of the living body by measuring a spectrum of the reflected light and the reference light;

an optical fiber that is configured to apply the laser light emitted from the light source onto a surface of the living body;

a second light receiving element that detects reflected light of the laser light applied by the optical fiber in a third direction different from the first and second directions, the reflected light being reflected by the surface of the living body; and

a light-source driving circuit that drives the light source on the basis of a detection signal from the second light receiving element so that an intensity of the laser light emitted from the light source is kept at a predetermined value.

2. The living-body component measuring apparatus according to claim 1, wherein the reference-light measuring unit includes:

a light collector that collects the reference light having the optical path changed by the beam splitter;

a pinhole that transmits the reference light collected by the light collector;

a first light receiving element that receives the reference light transmitted through the pinhole and outputs a data signal based on an amount of the received reference light; and

an A/D converter that subjects the data signal to A/D conversion and outputs the converted data signal to the analysis unit.

3. The living-body component measuring apparatus according to claim 1, further comprising:

a movement driving mechanism that three-dimensional moves the reflected-light measuring unit and the living body relative to each other so that a focal position of the reflected-light measuring unit is three-dimensional moved relative to the living body to obtain three-dimensional data on the inner tissue of the living body.

4. The living-body component measuring apparatus according to claim 1, wherein the analysis unit measures the component of the inner tissue on the basis of data standardized by dividing the detection signal for the reflected light from the inner tissue by the detection signal from the second light receiving element.

5. The living-body component measuring apparatus according to claim 1,

wherein the light source incorporates a third light receiving element that monitors the laser light emitted from the light source, and

wherein the light-source driving circuit drives the light source on the basis of at least one of the detection signal from the second light receiving element and a detection signal from the third light receiving element so that the intensity of the laser light emitted from the light source is kept at the predetermined value.

6. The living-body component measuring apparatus according to claim 1,

wherein the light source incorporates a third light receiving element that monitors the laser light emitted from the light source, and

wherein the analysis unit measures the component of the inner tissue on the basis of data standardized by dividing the detection signal for the reflected light from the inner tissue by at least one of the detection signal from the second light receiving element and a detection signal from the third light receiving element.

7. The living-body component measuring apparatus according to claim 1,

wherein the light source incorporates a third light receiving element that monitors the laser light emitted from the light source, and

wherein the analysis unit measures the component of the object on the basis of data obtained by linearly combining a first standardized signal obtained by dividing the detection signal for the reflected light from the inner tissue by the detection signal from the second light receiving element and a second standardized signal obtained by dividing the detection signal for the reflected light from the inner tissue by a detection signal from the third light receiving element.

8. The living-body component measuring apparatus according to claim 5, wherein the light-source driving circuit drives the light source on the basis of at least one of the detection signal from the second light receiving element, the detection signal from the third light receiving element, and a detection signal for the reference light so that the intensity of the laser light from the light source is kept at the predetermined value.

9. The living-body component measuring apparatus according to claim 8, wherein the analysis unit measures the component of inner tissue on the basis of data standardized by dividing the detection signal for the reflected light from the inner tissue by at least one of the detection signal from the second light receiving element, the detection signal from the third light receiving element, and the detection signal for the reference light.

10. The living-body component measuring apparatus according to claim 8, wherein the analysis unit measures the component of the inner tissue on the basis of data obtained by linearly combining signals standardized by dividing the detection signal for the reflected light from the inner tissue by the detection signal from the second light receiving element, the detection signal from the third light receiving element, and the detection signal for the reference light.

11. The living-body component measuring apparatus according to claim 1,

wherein the reflected-light measuring unit includes:

an objective lens that collects the laser light emitted from the light source and applies the laser light onto the inner tissue;

a second light collector that collects the reflected light having the optical path by changed by the beam splitter;

a second pinhole that transmits the reflected light collected by the second light collector;

a second light receiving element that receives the reflected light transmitted through the second pinhole and outputs a data signal based on an amount of the received reflected light; and

an A/D collector that subjects the data signal to A/D conversion and outputs the converted data signal to the analysis unit.

12. The living-body component measuring apparatus according to claim 6, wherein the light-source driving circuit drives the light source on the basis of at least one of the detection signal from the second light receiving element, the detection signal from the third light receiving element, and a detection signal for the reference light so that the intensity of the laser light from the light source is kept at the predetermined value.

13. The living-body component measuring apparatus according to claim 7, wherein the light-source driving circuit drives the light source on the basis of at least one of the detection signal from the second light receiving element, the detection signal from the third light receiving element, and a detection signal for the reference light so that the intensity of the laser light from the light source is kept at the predetermined value.

14. A living-body component measuring apparatus that measures a component of an inner tissue of a living body serving as an object to be measured, the living-body component measuring apparatus comprising:

a light source emitting laser light having two or more wavelengths;

a branching unit that branches the laser light emitted from the light source;

a reference-light measuring unit that measures, as reference light, one part of the laser light branched by the branching unit into a first direction;

a reflected-light measuring unit that measures the other part of the laser light branched by the branching unit into a second direction different from the first direction and serving as a reflected light of the laser light from the inner tissue of the living body;

an analysis unit that analyzes the inner tissue of the living body by measuring a spectrum of the reflected light and the reference light serving as the part of the laser light branched by the branching unit;

an optical fiber that is configured to apply the laser light emitted from the light source onto a surface of the living body;

a second light receiving element that detects reflected light of the laser light applied by the optical fiber in a third direction different from the first and second directions, the reflected light being reflected by the surface of the living body; and

a light-source driving circuit that drives the light source on the basis of a detection signal from the second light receiving element so that an intensity of the laser light emitted from the light source is kept at a predetermined value.

15. A living-body component measuring apparatus that measures a component of an inner tissue of a living body serving as an object to be, the living-body component measuring apparatus comprising:

a light source emitting laser light having two or more wavelengths;

a first beam splitter that transmits one part of the laser light emitted from the light source in a first direction and changes an optical path of the other part of the laser light into a second direction different from the first direction;

a second beam splitter that changes an optical path of the part of the laser light incident through the first beam splitter in the first direction, transmits the other part of the laser light in the first direction, and changes an optical path of a reflected light of the laser light from the inner tissue of the living body into a third direction different from the first direction;

a reference-light measuring unit that measures, as reference light, the other part of the laser light having the optical path changed by the first beam splitter in the second direction towards the reference-light measuring unit;

a reflected-light measuring unit that measures the reflected light reflected by the inner tissue of the living body and having the optical path changed by the second beam splitter in the third direction towards the reflected-light measuring unit;

an analysis unit that analyzes the inner tissue of the living body by measuring a spectrum of the reflected light and the reference light having the optical path changed by the first beam splitter;

an optical fiber that is configured to apply the laser light emitted from the light source onto a surface of the living body;

a second light receiving element that detects reflected light of the laser light applied by the optical fiber in a fourth direction different from the first, second and third directions, the reflected light being reflected by the surface of the living body; and

a light-source driving circuit that drives the light source on the basis of a detection signal from the second light receiving element so that an intensity of the laser light emitted from the light source is kept at a predetermined value.