Tunable laser-based spectroscopy system for non-invasively measuring body water content

• US 20080220512A1
• Filed: 03/09/2007
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Abandoned Application

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Debreczeny, Martin, Baker, Clark R., Koh, Seungug
• Application Number:
  US11/716,394
• Publication Number:
  US 20080220512A1
• Time in Patent Office: Days
• US Class Current: 435/288.7
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: G01N 21/39 using tunable lasers

Abstract

The present disclosure relates to a tunable laser-based spectroscopy system for accurately and non-invasively measuring body water content. The body water content is one of the important health indicators, by which one can quantitatively monitor the hydration level of body and determine if it is necessary to supplement or reduce the body water. The disclosed systems, devices, and/or methods may improve wavelength accuracy, wavelength resolution, optical spectral power density, signal-to-noise ration, and available implementation options for the spectroscopy system.

Claims

1. A system for assessing a body fluid metric, said device comprising:

a laser configured and arranged to illuminate at least a portion of a body tissue and a single detector in optical communication with the at least a portion of a body tissue.

2. A system according to claim 1 wherein the laser is a tunable laser.

3. A system according to claim 1 wherein the laser comprises one or more fixed wavelength lasers.

4. A system according to claim 1 further comprising a sensor comprising:

a first optic fiber having a first end that is configured and arranged to optically communicate with the laser and having a second end that is configured and arranged to optically communicate with a tissue sample; and

a second optic fiber having a first end that is configured and arranged to optically communicate with the detector and having a second end that is configured and arranged to optically communicate with a tissue sample.

5. A system according to claim 4 further comprising a wavelength division multiplexer in optical communication with the laser and the first optic fiber.

6. A system according to claim 4 further comprising an optical switch in optical communication with the laser and the first optic fiber.

7. A system according to claim 4 wherein the detector comprises a photodiode in optical communication with the second optic fiber.

8. A system according to claim 4 wherein the detector comprises an optical switch in optical communication with the second optic fiber.

9. A system according to claim 4 wherein the first optic fiber comprises a coupler.

10. A system according to claim 4 wherein the second optic fiber comprises a coupler.

11. A system according to claim 1 wherein the sensor is disposable.

12. A system according to claim 1 further comprising a collimator in optical communication with the laser.

13. A system according to claim 1 further comprising a beam expander in optical communication with the laser.

14. A system according to claim 1 further comprising a star coupler in optical communication with the laser.

15. A system according to claim 1 wherein the system exclude a diffraction grating.

16. A system according to claim 1 wherein the system excludes a detector array.

17. A sensor configured and arranged to releasably and operably contact a body fluid metric assessment system comprising a laser and a detector, said sensor comprising:

a first optic fiber having a first end that is configured and arranged to optically communicate with the laser and having a second end that is configured and arranged to optically communicate with a tissue sample; and

a second optic fiber having a first end that is configured and arranged to optically communicate with the detector and having a second end that is configured and arranged to optically communicate with a tissue sample.

18. A sensor according to claim 17 wherein the sensor is disposable.

19. A sensor according to claim 17 further comprising a wavelength division multiplexer in optical communication with the first optic fiber and configured and arranged to optically communicate with the laser.

20. A sensor according to claim 17 further comprising an optical switch in optical communication with the first optic fiber and configured and arranged to optically communicate with the laser.

21. A sensor according to claim 17 further comprising an optical switch in optical communication with the second optic fiber and configured and arranged to optically communicate with the detector.

22. A sensor according to claim 17 further comprising a collimator in optical communication with the first optic fiber and configured and arranged to optically communicate with the laser.

23. A sensor according to claim 17 further comprising a beam expander in optical communication with the first optic fiber and configured and arranged to optically communicate with the laser.

24. A sensor according to claim 17 wherein the first optic fiber comprises a coupler.

25. A sensor according to claim 17 wherein the second optic fiber comprises a coupler.

26. A sensor configured and arranged to releasably and operably contact a body fluid metric assessment system comprising a tunable laser and a processor, said sensor comprising:

an optic fiber having a first end that is configured and arranged to optically communicate with the tunable laser and having a second end that is configured and arranged to optically communicate with a tissue sample;

a photodiode configured and arranged to optically communicate with a tissue sample; and

a wire having a first end in electrical communication with the photodiode and a second end configured and arranged to electrically communicate with the processor.

27. A method of assessing a body fluid metric, said method comprising:

illuminating at least a portion of a body tissue with a laser;

detecting at least one wavelength of light emanating from the at least a portion of a body tissue using a single detector; and

processing the detected at least one wavelength of light emanating from the at least a portion of a body tissue to produce a body fluid metric.

28. A method according to claim 27 wherein the laser is a tunable laser.

29. A method according to claim 28 wherein the illuminating further comprises emitting light of a selected discrete wavelength from the tunable laser.

30. A method according to claim 27 wherein the illuminating further comprises emitting light from the laser toward an optical switch and selecting a wavelength of light with which to illuminate the at least a portion of a body tissue using the optical switch.

31. A method according to claim 27 wherein the illuminating further comprises emitting light from the laser toward a collimator and selecting a wavelength of light with which to illuminate the at least a portion of a body tissue using the collimator.

32. A method according to claim 27 wherein the illuminating further comprises emitting light from the laser toward a wavelength division multiplexer, splitting the emitted light into two or more beams using the wavelength division multiplexer, and illuminating a number of at least a portion of body tissues corresponding to the number of beams.

33. A method according to claim 32 wherein each at least a portion of body tissues is comprised in a single subject.

34. A method according to claim 32 wherein each at least a portion of body tissues is comprised in a separate subject.

35. A method according to claim 32 wherein the wavelength of light in each beam differs from the wavelength in the other beams.

36. A method according to claim 32 wherein the wavelength of light in each beam is the same as the wavelength in the other beams.

37. A method according to claim 27 wherein the illuminating further comprises emitting light from the laser toward an optical switch, splitting the emitted light into two or more beams using the optical switch, and illuminating a number of at least a portion of body tissues corresponding to the number of beams.

38. A method according to claim 37 wherein the wavelength of light in each beam differs from the wavelength in the other beams.

39. A method according to claim 37 wherein the wavelength of light in each beam is the same as the wavelength in the other beams.

40. A method according to claim 27 wherein the processing comprises comparing the detected at least one wavelength with a reference to form a comparison and using the comparison to determine the hydration status of the at least a portion of a body tissue.

41. A method according to claim 40 wherein the reference comprises at least a portion of an absorption spectrum for a reference tissue.

42. A method according to claim 41 wherein the comparing to form a comparison further comprises evaluating the difference between the detected at least one wavelength and at least one wavelength having a corresponding degree of absorption in the reference.

43. A method according to claim 42 wherein the evaluating further comprises quantitatively evaluating the difference between the detected at least one wavelength and the reference.

44. A method according to claim 42 wherein the evaluating further comprises qualitatively evaluating the difference between the detected at least one wavelength and the reference.

45. A method according to claim 42 wherein the absorption spectra for a reference tissue is from about 1450 nm to about 1650 nm and the reference tissue is normally hydrated tissue.

46. A method according to claim 45 wherein the comparing to form a comparison further comprises evaluating the difference between the detected at least one wavelength and the at least one wavelength having a corresponding degree of absorbance in the reference.

47. A method according to claim 46 wherein an increase in the at least one wavelength by at least a predetermined amount indicates over-hydration.

48. A method according to claim 46 wherein a decrease in the at least one wavelength by at least a pre-determined amount indicates dehydration.

49. A method according to claim 43 wherein the processing comprises comparing the detected at least one wavelength with a reference to form a comparison and using the comparison to determine the hydration status of the at least a portion of a body tissue.

50. A method according to claim 49 wherein the reference comprises at least a portion of an absorption spectrum for a reference tissue.

51. A method according to claim 50 wherein the comparing to form a comparison comprises evaluating the difference between the detected at least one wavelength and at least one wavelength having a corresponding degree of absorption in the reference.

52. A method according to claim 51 wherein the reference tissue is normally hydrated tissue.

53. A method according to claim 52 wherein the comparing to form a comparison comprises evaluating the difference between the detected at least one wavelength and the at least one wavelength having a corresponding degree of absorbance in the reference.

54. A method according to claim 53, wherein the two or more beams comprise a first beam comprising light with a wavelength of about 1390 nm and a second beam comprising light with a wavelength of about 1860 nm.

55. A method according to claim 53, wherein the two or more beams comprise a first beam comprising light with a wavelength of about 1392 nm and a second beam comprising light with a wavelength of about 1860 nm.

56. A method according to claim 53, wherein the two or more beams comprise a first beam comprising light with a wavelength of about 1380 nm, a second beam comprising light with a wavelength of about 1680 nm, and a third beam comprising light with a wavelength of about 1835 nm.

57. A method according to claim 53, wherein the two or more beams comprise a first beam comprising light with a wavelength of about 1383 nm, a second beam comprising light with a wavelength of about 1682 nm, and a third beam comprising light with a wavelength of about 1838 nm.

58. A method according to claim 53, wherein the two or more beams comprise a first beam comprising light with a wavelength of about 1395 nm, a second beam comprising light with a wavelength of about 1640 nm, a third beam comprising light with a wavelength of about 1665 nm, and a forth beam comprising light with a wavelength of about 1835 nm.

59. A method according to claim 53, wherein the two or more beams comprise a first beam comprising light with a wavelength of about 1397 nm, a second beam comprising light with a wavelength of about 1642 nm, a third beam comprising light with a wavelength of about 1667 nm, and a forth beam comprising light with a wavelength of about 1687 nm.