Chemical imaging fiberscope

• US 7,239,782 B1
• Filed: 09/03/2004
• Issued: 07/03/2007
• Est. Priority Date: 09/03/2004
• Status: Active Grant

• Current Assignee: Chemimage Corporation
• Original Assignee: Chemimage Corporation
• Inventors: Nelson, Matthew P., Treado, Patrick J., Keitzer, Scott A., Smith, Ryan D.
• Primary Examiner(s): AMARI, ALESSANDRO V
• Application Number:
  US10/934,885
• Time in Patent Office: 1,033 Days
• Field of Search: 385/115, 385/116, 385/117, 385/119, 356/301, 600/160, 600/178, 600/179, 600/181, 600/182
• US Class Current: 385/117
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 1/043 for fluorescence imaging
• CPC Class Codes: A61B 1/063 for monochromatic or narrow-band illumination
• CPC Class Codes: A61B 1/0638 providing two or more wavelengths
• CPC Class Codes: A61B 1/0646 with illumination filters
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: G01J 2003/1213 Filters in general, e.g. dichroic, band
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/024 using means for illuminating a slit efficiently (e.g. entrance slit of a spectrometer or entrance face of fiber)
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/0286 Constructional arrangements for compensating for fluctuations caused by temperature, humidity or pressure, or using cooling or temperature stabilization of parts of the device; Controlling the atmosphere inside a spectrometer, e.g. vacuum
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G02B 6/06 the relative position of the fibres being the same at both ends, e.g. for transporting images

Abstract

A fiberscope device is disclosed which is suitable for video imaging, laser Raman spectroscopy and laser Raman spectroscopic (i.e. chemical) imaging. The fiberscope design minimizes fiber background interference arising from the laser delivery fiber optic and the coherent fiber optic light gathering bundle while maintaining high light throughput efficiency through the use of integrated spectral filters. In the fiberscope design, the laser delivery fiber optic is offset from the coherent fiber optic light gathering bundle. The laser delivery field is captured entirely by the light gathering field of view of the coherent fiber bundle. The fiberscope incorporates spectral filter optical elements that provide environmental insensitivity, particularly to temperature and moisture. The fiberscope is suited to the analysis of a wide range of condensed phase materials (solids and liquids), including the analysis of biological materials such as breast tissue lesions and arterial plaques, in such a manner to delineate abnormal from normal tissues.

Claims

1. A chemical imaging fiberscope for imaging and collecting Raman spectra from a sample comprising:

one or more laser illumination fibers for transmitting laser light of a specific laser excitation wavelength from a first source to said sample;

a plurality of collection fibers, for receiving light scattered from said sample;

a first portion of a spectral filter positioned between said one or more laser illumination fibers and said sample for transmitting said laser light of a specific laser excitation wavelength and rejecting light of other wavelengths; and

a second portion of the spectral filter positioned between said sample and said plurality of collection fibers for transmitting wavelengths of light other than said specific laser excitation wavelength;

wherein the spectral filter is spatially patterned into the first portion for filtering said laser light and a second, transparent portion for transmitting light scattered or reflected by said sample to said plurality of collection fibers.

2. The chemical imaging fiberscope of claim 1 wherein said plurality of collection fibers are arranged in a coherent bundle.

3. The chemical imaging fiberscope of claim 1 wherein at least one of said first or second spectral filters exhibit environmental insensitivity to temperature and humidity.

4. The chemical imaging fiberscope of claim 1 further comprising one or more lenses positioned between said sample and said plurality of collection fibers.

5. The chemical imaging fiberscope of claim 1 further comprising a housing for enclosing the fiberscope.

6. The chemical imaging fiberscope of claim 5 further comprising a window disposed at the distal end of said fiberscope.

7. The chemical imaging fiberscope of claim 6 wherein said window is composed of a material selected from a group comprising quartz, diamond and sapphire.

8. The fiberscope assembly of claim 1 wherein said first or second spectral filters are composed of a filter type selected from a group comprising dielectric, holographic and rugate spectral filters.

9. The chemical imaging fiberscope of claim 1 further comprising a plurality of white light illumination fibers for transmitting white light from a second source to said sample.

10. The chemical imaging fiberscope of claim 9 wherein said plurality of collection fibers are arranged in a coherent bundle.

11. The chemical imaging fiberscope of claim 9 wherein at least one of said first or second spectral filters exhibit environmental insensitivity to temperature and humidity.

12. The chemical imaging fiberscope of claim 11 further comprising one or more lenses positioned between said sample and said collection.

13. The chemical imaging fiberscope of claim 9 further comprising a housing for enclosing the fiberscope.

14. The chemical imaging fiberscope of claim 13 further comprising a window disposed at the distal end of said fiberscope.

15. The chemical imaging fiberscope of claim 14 wherein said window is composed of a material selected from a group comprising quartz, diamond and sapphire.

16. The fiberscope assembly of claim 9 wherein said first spectral filter is spatially patterned into a first portion for filtering said laser light and a second, transparent portion for transmitting light scattered or reflected by said sample to said plurality of collection fibers.

17. The chemical imaging fiberscope of claim 16 wherein said spectral filters exhibit environmental insensitivity to temperature and humidity.

18. The chemical imaging fiberscope of claim 9 further comprising a spatial filter positioned between said sample and said collection fibers for controlling the angular field of view of said collection fibers.

19. The chemical imaging fiberscope of claim 1 further comprising a spatial filter positioned between said sample and said collection fibers for controlling the angular field of view of said collection fibers.

20. A chemical imaging fiberscope of claim 1 further comprising:

a mount for holding the fiberscope distal end in proximity to said sample;

a link for directing the output of the fiberscope under white light illumination conditions to a live video camera;

a link for directing the output under laser illumination conditions to a Raman spectrometer;

a link for directing the output under laser illumination conditions to a Raman chemical imaging spectrometer and detector.

21. A chemical imaging fiberscope for imaging and collecting Raman spectra from a sample comprising:

one or more laser illumination fibers for transmitting laser light of a specific laser excitation wavelength from a first source to said sample;

a plurality of collection fibers for receiving light scattered from said sample;

a first portion of a spectral filter positioned between said one or more laser illumination fibers and said sample for transmitting said laser light of a specific laser excitation wavelength and rejecting light other wavelengths;

a second portion of the spectral filter positioned between said sample and said plurality of collection fibers for transmitting wavelengths of light other than said specific laser excitation wavelength;

wherein the first portion is spatially patterned for filtering said laser light and the second portion is configured for transmitting light scattered or reflected by the sample to the plurality of collection fibers;

a spatial filter positioned between said sample and said collection fibers for controlling the angular field of view of said collection fibers;

one or more lenses positioned between said sample and said plurality of collection fibers;

a housing for enclosing the fiberscope; and

a window disposed at the distal end of said fiberscope.

22. A chemical imaging fiberscope for illuminating and collecting light from a sample comprising:

a plurality of laser illumination fibers for transmitting laser light of a specific laser excitation wavelength from a first source to said sample via a first optical path;

a plurality of white light illumination fibers for transmitting white light from a second source to said sample via a second optical path;

a plurality of collection fibers for receiving light scattered or reflected from said sample and transmitting said scattered or reflected light to an imaging apparatus via a third optical path; and

a housing for enclosing the fiberscope,

wherein said first optical path is different from said second optical path and wherein said first and third optical paths each include a spectral filter.

23. The chemical imaging fiberscope of claim 22 wherein said first optical path comprises said laser illumination fibers, a first portion of a spectral filter, and a window disposed at the distal end of said fiberscope.

24. The chemical imaging fiberscope of claim 23 wherein said second optical path comprises said white light illumination fibers and said window.

25. The chemical imaging fiberscope of claim 24 wherein said third optical path comprises said window and a second portion of said spectral filter.

26. The chemical imaging fiberscope of claim 25 wherein said first portion of the spectral filter is spatially patterned for filtering said laser light and said second portion of the spectral filter is transparent for transmitting light scattered or reflected by said sample to said collection fibers.

27. The chemical imaging fiberscope of claim 26 wherein said third optical path comprises said window, said second portion of said spectral filter, a spatial filter, a lens, a reflection filter, and said collection fibers.

28. The chemical imaging fiberscope of claim 22 wherein said first and second optical paths are each different from said third optical path.

29. The chemical imaging fiberscope of claim 22 wherein a first portion of said spectral filter is spatially patterned for filtering said laser light and a second portion of said spectral filter is transparent for transmitting light scattered or reflected by said sample to said collection fibers.

30. The chemical imaging fiberscope of claim 22 wherein said spectral filter exhibits environmental insensitivity to temperature and humidity.

31. The chemical imaging fiberscope of claim 22 wherein said spectral filter is composed of a filter type selected from a group comprising dielectric, holographic and rugate spectral filters.

32. The chemical imaging fiberscope of claim 22 wherein said plurality of collection fibers are arranged in a coherent bundle.

33. The chemical imaging fiberscope of claim 22 further comprising one or more lenses.

34. The chemical imaging fiberscope of claim 33 wherein said lenses are disposed in said third optical path.

35. The chemical imaging fiberscope of claim 22 further comprising a window disposed at a distal end of said fiberscope.

36. The chemical imaging fiberscope of claim 35 wherein said window is composed of a material selected from a group comprising quartz, diamond and sapphire.

37. The chemical imaging fiberscope of claim 22 wherein said imaging apparatus comprises a spectrometer.

38. The chemical imaging fiberscope of claim 37 wherein said spectrometer is a Raman spectrometer.

39. The chemical imaging fiberscope of claim 22 wherein said imaging apparatus includes a tunable filter.

40. The chemical imaging fiberscope of claim 39 wherein said tunable filter is a liquid crystal tunable filter.

41. The chemical imaging fiberscope of claim 22 wherein said imaging apparatus produces a Raman image of said sample.

42. The chemical imaging fiberscope of claim 22 wherein said imaging apparatus produces a chemical image of said sample.

43. The chemical imaging fiberscope of claim 22 wherein said imaging apparatus comprises a charge-coupled device.

44. The chemical imaging fiberscope of claim 43 wherein said charge-coupled device is a video charge-coupled device.