In-vivo information measurement apparatus

• US 20050267340A1
• Filed: 03/22/2005
• Published: 12/01/2005
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Takizawa, Hironobu, Miura, Naoki, Ishihara, Yasushige, Xie, Tianyu
• Granted Patent: US 8,060,172 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence

Abstract

An in-vivo information measurement apparatus comprises an insertion part; a light projection unit, provided at a tip of the insertion part, that irradiates an examination site with intensity-modulated light which is intensity modulated at a first frequency; a light receiving unit that receives return light from the examination site; an optical detector that detects return light; an in-vivo information calculation unit that calculates in-vivo information for the examination site based on a phase shift between a modulated detection signal, in which a detection signal from the optical detector is modulated at a second frequency, and a reference signal having a difference frequency equal to the difference between the first frequency and the second frequency; and a position moving mechanism that moves at least one of a position at which the intensity-modulated light is emitted by the light projection unit and the position at which the return light is incident on the light receiving unit. The apparatus can easily and efficiently measure the distribution of in-vivo information in directions in the plane of the examination site and in the depth direction of the examination site over a comparatively wide region with a compact configuration, and without requiring a large area where it is inserted into the body cavity.

Claims

1. An in-vivo information measurement apparatus comprising:

an insertion part for insertion into a body cavity;

a light projection unit, provided at a tip of the insertion part, that irradiates an examination site inside the body cavity with intensity-modulated light intensity modulated at a first frequency;

a light receiving unit that receives return light from the examination site at a different position from the light projection unit;

an optical detector that detects return light from the examination site received at the light receiving unit;

an in-vivo information calculation unit that calculates in-vivo information for the examination site based on a phase shift between a modulated detection signal, formed by modulating a detection signal from the optical detector at a second frequency, and a reference signal having a difference frequency equal to the difference between the first frequency and the second frequency; and

a position moving mechanism that moves at least one of a position at which the intensity-modulated light is emitted by the light projection unit and the position at which the return light is incident on the light receiving unit.

2. An in-vivo information measurement apparatus according to claim 1, wherein the insertion part is an endoscope.

3. An in-vivo information measurement apparatus according to claim 1, wherein the insertion part is an elongated probe.

4. An in-vivo information measurement apparatus according to claim 1, further comprising:

an illumination unit that irradiates the examination site with illumination light;

an objective optical system that forms an image of the examination site; and

an imaging unit that acquires the image formed by the objective optical system,

wherein the insertion part includes an endoscope and an elongated probe, and

the elongated probe is disposed inside the endoscope.

5. An in-vivo information examination apparatus according to claim 4, wherein at least one of the light projection unit and the light receiving unit is disposed inside the field of view of the objective optical system.

6. An in-vivo information measurement apparatus according to claim 4, further comprising:

an image combining device that superimposes the endoscope image obtained by the endoscope and the in-vivo information for the examination site calculated by the in-vivo information calculation unit.

7. An in-vivo information measurement apparatus according to claim 3, wherein the probe can be inserted into a channel of the endoscope.

8. An in-vivo information measurement apparatus according to claim 1, further comprising:

a plurality of optical fibers in the insertion part,

wherein at least one of the light projection unit and the light receiving unit is constituted by end faces of the optical fibers, and

the position moving mechanism includes an optical fiber selection mechanism that selects an optical fiber for guiding the intensity-modulated light to be irradiated or the return light to be detected.

9. An in-vivo information measurement apparatus according to claim 8, wherein the light projection unit and the light receiving unit are both constituted by the end face of a common optical fiber.

10. An in-vivo information measurement apparatus according to claim 8, wherein the plurality of optical fibers are formed of a fiber bundle.

11. An in-vivo information measurement apparatus according to claim 8, wherein

the light projection unit is constituted by end faces of the optical fibers;

and

the optical fiber selection mechanism includes a scanning mirror that varies the angle at which the intensity-modulated light is reflected to select the optical fiber into which the intensity-modulated light is introduced.

12. An in-vivo information measurement apparatus according to claim 8, wherein

the light receiving unit is constituted by end faces of the optical fibers, and

the optical fiber selection mechanism includes a scanning mirror that varies the angle at which return light which is received at the light receiving unit and transmitted through the optical fiber is reflected to selectively introduce the return light to the optical detector.

13. An in-vivo information measurement apparatus according to claim 11, wherein the scanning mirror is formed of a galvano mirror.

14. An in-vivo information measurement apparatus according to claim 12, wherein the scanning mirror is formed of a galvano mirror.

15. An in-vivo information measurement apparatus according to claim 11, wherein the scanning mirror is formed of a MEMS mirror array.

16. An in-vivo information measurement apparatus according to claim 12, wherein the scanning mirror is formed of a MEMS mirror array.

17. An in-vivo information measurement apparatus according to claim 1, wherein the position moving mechanism includes a moving mechanism that moves the light projection unit or the light receiving unit over a surface inside the body cavity.

18. An in-vivo information measurement apparatus according to claim 17, wherein the moving mechanism rotates the light projection unit or the light receiving unit about an axis of an endoscope.

19. An in-vivo information measurement apparatus according to claim 17, wherein the moving mechanism translates the light projection unit or the light receiving unit along an axis of an endoscope.

20. An in-vivo information measurement apparatus according to claim 1, wherein the position moving mechanism includes a scanning mirror that reflects the intensity-modulated light to scan the examination site.

21. An in-vivo information measurement apparatus according to claim 1, further comprising:

an in-vivo information display unit that displays in-vivo information for the examination site, which is calculated by the in-vivo information calculation unit.

22. An in-vivo information measurement apparatus according to claim 21, wherein

the insertion part is an endoscope, and

the in-vivo information display unit simultaneously displays an image of the surface of the examination site, which is acquired by the endoscope, and the in-vivo information for the examination site.

23. An in-vivo information measurement apparatus according to claim 21, wherein the in-vivo information display unit multi-dimensionally displays the in-vivo information for the examination site.

24. An in-vivo information measurement apparatus according to claim 1, further comprising:

a wavelength selection mechanism, between the light receiving unit and the optical detector, for selectively detecting in the optical detector light of a predetermined wavelength among the return light.

25. An in-vivo information measurement apparatus according to claim 24, wherein the wavelength selection mechanism is formed of a dichroic mirror.

26. An in-vivo information measurement apparatus according to claim 24, wherein the wavelength selection mechanism is formed of a filter that transmits only fluorescence or phosphorescence among the return light.

27. An in-vivo information measurement apparatus according to claim 1, wherein the optical detector is formed of a photodetector array.

28. An in-vivo information measurement apparatus according to claim 1, wherein the optical detector is formed of a charge coupled device.

29. An in-vivo information measurement apparatus according to claim 1, further comprising:

a light source; and

a modulator that intensity modulates light from the light source at a first frequency,

wherein the light source is constructed so as to be capable of emitting a plurality of different wavelengths of light.

30. An in-vivo information measurement apparatus according to claim 1, wherein the in-vivo information is the concentration of biological tissue components.

31. An in-vivo information measurement apparatus according to claim 30, wherein the biological tissue components are any of oxygen, hemoglobin, oxygenated hemoglobin, deoxygenated hemoglobin, water, and carbon dioxide.

32. An in-vivo information measurement apparatus comprising:

a light projection unit that irradiates an examination site inside a body cavity with intensity-modulated light which is intensity modulated at a first frequency;

a light receiving unit that receives return light from the examination site at a different position from the light projection unit;

an optical detector that detects the return light received in the light receiving unit;

an in-vivo information calculating unit that calculates in-vivo information for the examination site based on a phase shift between a modulated detection signal, formed by modulating a detection signal from the optical detector at a second frequency, and a reference signal having a difference frequency equal to the difference between the first frequency and the second frequency; and

an optical scanning unit that scans at least one of the intensity-modulated light from the light projection unit and the return light from the light receiving unit.

33. An in-vivo information measurement apparatus according to claim 32, wherein the scanning unit is a scanning mirror.

34. An in-vivo information measurement apparatus according to claim 33, wherein at least one of the light projection unit and the light receiving unit is constituted by end faces of optical fibers;

and

an optical fiber for guiding the intensity-modulated light to be irradiated or the return light to be detected is selected by the scanning mirror.

35. An in-vivo information measurement apparatus according to claim 33, wherein the scanning mirror is formed of a MEMS mirror array.

36. An in-vivo information measurement apparatus according to claim 32, further comprising:

an insertion part that can be inserted into the body cavity.

37. An in-vivo information measurement apparatus according to claim 36, wherein the optical scanning unit is provided at a tip of the insertion part.

38. An in-vivo information measurement apparatus according to claim 36, wherein the optical scanning unit is provided on the outer side of the insertion part.