Medical imaging, diagnosis, and therapy using a scanning single optical fiber system

• US 6,975,898 B2
• Filed: 05/07/2001
• Issued: 12/13/2005
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Washington University In St Louis
• Original Assignee: University of Washington
• Inventors: Seibel, Eric J.
• Primary Examiner(s): Shaw, Shawna J
• Application Number:
  US09/850,594
• Publication Number:
  US 20010055462A1
• Time in Patent Office: 1,681 Days
• Field of Search: 600/473, 600/476, 600/478, 600/160, 600/166, 600/178, 600/181, 600/182, 607/89, 607/92, 385/117, 385/118, 385/130, 385/147, 356/301, 356/319, 356/320, 356/326, 250/208.1, 250/458.1, 250/459.1, 250/461.1, 250/461.2
• US Class Current: 600/473
• CPC Class Codes: A61B 1/00048 Constructional features of the display
• CPC Class Codes: A61B 1/0008 characterised by distal tip features
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 1/00167 Details of optical fibre bundles, e.g. shape or fibre distribution
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00183 for variable viewing angles
• CPC Class Codes: A61B 1/00193 adapted for stereoscopic vision
• CPC Class Codes: A61B 1/0051 with controlled bending of insertion part
• CPC Class Codes: A61B 1/009 with bending or curvature detection of the insertion part
• CPC Class Codes: A61B 1/043 for fluorescence imaging
• CPC Class Codes: A61B 1/0638 providing two or more wavelengths
• CPC Class Codes: A61B 1/0655 Control therefor
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0068 Confocal scanning
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• 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: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: A61N 2005/063 : comprising light transmitting means, e.g. optical fibres
• CPC Class Codes: A61N 5/0601 : Apparatus for use inside the body
• CPC Class Codes: A61N 5/062 : Photodynamic therapy, i.e. excitation of an agent
• CPC Class Codes: G02B 26/10 : Scanning systems
• CPC Class Codes: G02B 6/241 : Light guide terminations
• CPC Class Codes: G02B 6/262 : Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/32 : having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/3502 : involving direct waveguide displacement, e.g. cantilever type waveguide displacement involving waveguide bending, or displacing an interposed waveguide between stationary waveguides
• CPC Class Codes: G02B 6/3566 : involving bending a beam, e.g. with cantilever
• CPC Class Codes: G02B 6/357 : Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3572 : Magnetic force magnetic forces controlling reflecting elements in general G02B26/085; magneto-optic devices G02F1/09
• CPC Class Codes: G02B 6/3578 : Piezoelectric force piezoelectric forces controlling reflecting elements in general G02B26/0858; piezo-optic devices G02F1/0131

Abstract

An integrated endoscopic image acquisition and therapeutic delivery system for use in minimally invasive medical procedures (MIMPs). The system uses directed and scanned optical illumination provided by a scanning optical fiber or light waveguide that is driven by a piezoelectric or other electromechanical actuator included at a distal end of an integrated imaging and diagnostic/therapeutic instrument. The directed illumination provides high resolution imaging, at a wide field of view (FOV), and in full color that matches or excels the images produced by conventional flexible endoscopes. When using scanned optical illumination, the size and number of the photon detectors do not limit the resolution and number of pixels of the resulting image. Additional features include enhancement of topographical features, stereoscopic viewing, and accurate measurement of feature sizes of a region of interest in a patient'"'"'s body that facilitate providing diagnosis, monitoring, and/or therapy with the instrument.

Claims

1. Apparatus for selectively providing imaging and at least one other function for a region of interest in a patient, comprising:

(a) at least one light source that produces light;

(b) a light guide having a proximal end and a distal end, the at least one light source being optically coupled to the proximal end of said light guide, so that light from all of said at least one light source is conveyed along a single optical path defined by the light guide toward a region of interest, said distal end of the light guide being adapted to be positioned adjacent to a region of interest;

(c) a scanning actuator disposed adjacent to the distal end of the light guide, said scanning actuator driving a distal end of the light guide into a resonance movement mode, causing light produced by the at least one light source that is conveyed through the light guide to scan a region of interest, illuminating only a pixel at a time in regard to an image of a region of interest;

(d) a light detector that receives light from each pixel that is illuminated by the scanning actuator in a region of interest, producing a signal corresponding to an intensity of said light for use in producing an image of a region of interest;

(e) a display adapted to enable a user to visualize an image of a region of interest; and

(f) a control circuit that is coupled to control the scanning actuator, the at least one light source, and the light guide, said control circuit being adapted to selectively energize the at least one light source to image a region of interest and render at least one other function to a region of interest, said at least one other function including at least one of diagnosing a condition, rendering a therapy, sensing a condition, and monitoring a condition.

2. The apparatus of claim 1, wherein the at least one light source comprises a plurality of light sources that emit light of different colors, further comprising a combiner that combines the light of different colors emitted by the plurality of light sources for input to the proximal end of the light guide.

3. The apparatus of claim 2, wherein the light detector comprises a plurality of light sensors that are each sensitive to one of the different colors of light emitted by the plurality of light sources.

4. The apparatus of claim 3, further comprising a polarizing filter adapted to be disposed between at least one of:

(a) the at least one light source and a region of interest, so that a region of interest is illuminated with a polarized illumination light; and

(b) the region of interest and at least one light sensor.

5. The apparatus of claim 4, wherein the light detector detects polarized light having a predefined axis of polarization.

6. The apparatus of claim 1, wherein the light detector comprises a plurality of light sensors that are disposed adjacent to the distal end of the optical fiber.

7. The apparatus of claim 6, further comprising a plurality of light guides that convey the light reflected from a region of interest to the plurality of light sensors.

8. The apparatus of claim 7, wherein different portions of the plurality of light guides are adapted to convey light collected from within a region of interest, using light sensors that are spaced apartf from each other, enabling a quasi-stereo image of a region of interest to be visualized by a user with the display.

9. The apparatus of claim 7, wherein different portions of the plurality of light guides are adapted to convey light collected from within a region of interest using light sensors that are spaced-apart from each other, to substantially reduce an effect of specular reflections in an image of the region of interest.

10. The apparatus of claim 1, further comprising a plurality of light guides having proximal ends and distal ends, wherein the light detector comprises a plurality of light sensors that are coupled to the proximal end of the light guides.

11. The apparatus of claim 10, wherein said at least one additional light guide uses at least one of cladding and a concentric region of appropriate refractive index to propagate light through the light guides toward the plurality of light sensors that are coupled to the distal end of the light guides.

12. The apparatus of claim 11, wherein the light guides comprise a concentric optical fiber assembly that conveys light bi-directionally to and from the region of interest.

13. The apparatus of claim 1, wherein the scanning actuator comprises at least one electromechanical actuator that moves the distal end of the light guide in a two-dimensional scanning mode.

14. The apparatus of claim 1, wherein the scanning actuator comprises a piezoceramic actuator that is energized at a harmonic of a resonant frequency of the distal end of the light guide, causing the light guide to oscillate.

15. The apparatus of claim 1, wherein the light guide comprises an optical fiber, and wherein the distal end of the optical fiber is tapered to a substantially smaller cross-sectional size than a more proximal portion of the optical fiber.

16. The apparatus of claim 1, further comprising at least one lens adapted to be disposed between the distal end of the light guide and a region of interest, said at least one lens being adapted to focus the light produced by the at least one light source onto a region of interest.

17. The apparatus of claim 16, wherein said at least one lens comprises a lens mounted at the distal end of the light guide, said scanning actuator being adapted to drive the distal end of the light guide in a resonance mode to scan a region of interest, said lens that is mounted at the distal end of the light guide having sufficient mass so that the lens generally rotates as the light guide moves to change a direction in which light is emitted, when scanning a region of interest.

18. The apparatus of claim 1, wherein the light guide comprises a first thin film optical waveguide disposed at the distal end of the light guide so that the light emitted by the at least one light source passes through the first thin film optical waveguide and is thus adapted to be directed onto a region of interest.

19. The apparatus of claim 18, wherein the scanning actuator is disposed adjacent to the first thin film optical waveguide and moves the first thin film optical waveguide, being thereby adapted to cause the light to scan a region of interest.

20. The apparatus of claim 18, wherein the light guide comprises a second thin film optical waveguide disposed at the distal end of the light guide and moved generally in parallel with the first thin film optical waveguide and thereby adapted to scan a region of interest in parallel with the first thin film optical waveguide.

21. The apparatus of claim 20, wherein one of the first and second thin film optical waveguides images the region of interest, while the other of the first and second thin film optical waveguides renders said at least one other function in regard to the region of interest.

22. The apparatus of claim 18, wherein the thin film optical waveguide has a cross-sectional size less than 0.01 mm.

23. The apparatus of claim 1, wherein the at least one light source is adapted to provide at least one of a visible light, an ultraviolet light, and an infrared light to illuminate a region of interest.

24. The apparatus of claim 23, wherein the light detector is responsive to at least one of a visible light, an ultraviolet light, and an infrared light.

25. The apparatus of claim 1, wherein the light detector is responsive to light emitted from a region of interest due to one of phosphorescence and fluorescence.

26. The apparatus of claim 1, further comprising at least one of a spectrophotometer and a spectrum analyzer coupled to the light detector for use in diagnosing a condition of a region of interest.

27. The apparatus of claim 1, further comprising a thermal detector coupled to one of the proximal and distal ends of the light guide for use in monitoring a temperature in a region of interest.

28. The apparatus of claim 1, wherein the display comprises a stereo display that enables a user to visualize a quasi-stereo image of a region of interest.

29. The apparatus of claim 1, further comprising means for guiding and maneuvering the distal end of the light guide to a region of interest within a patient.

30. The apparatus of claim 1, further comprising a balloon disposed adjacent to the distal end of the light guide, said balloon being adapted to stabilize the distal end of the light guide in a cavity within a patient when the balloon is inflated.

31. The apparatus of claim 1, further comprising electrical leads that extend along the light guide, to its distal end, said electrical leads being connected to the scanning actuator to energize it.

32. The apparatus of claim 1, further comprising sensors that monitor movement of the distal end of the light guide and which are coupled to the control circuit to enable the scanning actuator to be controlled when scanning the region of interest.

33. A method for using an integral light guide system to selectively image and carry out at least one other substantive function in connection with a region of interest in a patient, said method comprising the steps of:

(a) directing a light at the region of interest in the patient through a light guide;

(b) scanning the region of interest with the light by moving the light guide, wherein the step of scanning comprises the step of driving a distal end of the light guide into a resonance movement mode, so that the region of interest is illuminated with the light a pixel at a time, in regard to an image of the region of interest;

(c) detecting light from the region of interest and in response thereto, producing signals indicative of characteristics of said light, including an intensity of the light received from the region of interest;

(d) imaging the region of interest, using the signals produced by the step of detecting; and

(e) controlling the administration of the light to the region of interest through the light guide, to selectively carry out at least one of the steps of;

(i) monitoring the region of interest;

(ii) determining a biophysical condition of the region of interest; and

(iii) rendering therapy to the region of interest with the light directed thereon.

34. The method of claim 33, further comprising the step of receiving light from the region of interest at a plurality of spaced-apart locations, said step of imaging comprising the step of enabling a user to visually perceive a quasi-stereo image of the region of interest.

35.The method of claim 34, further comprising the step of substantially reducing an effect of specular reflection from the region of interest, using the light received from the plurality of spaced-apart locations.

35. The method of claim 33, wherein the step of scanning comprises the step of causing the light guide to move so that the light emitted from the light guide scans over the region of interest in two generally orthogonal directions.

36. The method of claim 33, wherein the step of scanning comprises the step of causing the light guide to move so that the light emitted from the light guide scans over the region of interest in a helical arc.

37. The method of claim 33, wherein the step of scanning comprises the step of causing the light guide to move so that the light emitted from the light guide scans the region of interest in at least one of:

(a) generally concentric circles of different radii; and

(b) a propeller scan mode.

38. The method of claim 33, further comprising the step of focusing the light onto the region of interest through a lens.

41. The method of claim 33, wherein a distal end of the light guide comprises a thin film optical waveguide, said step of scanning comprising the step of causing the thin film optical waveguide to move so that light emitted thereby is scanned over the region of interest.

42. The method of claim 33, wherein the light directed to the region of interest comprises a high intensity laser light that is directed at undesired tissue on the region of interest to cause the undesired tissue to be destroyed.

43. The method of claim 33, further comprising the step of selectively screening the region of interest to detect any pathological condition associated with the region of interest.

44. The method of claim 33, further comprising the step of selectively sensing a natural biological state of the region of interest to detect a pathological condition.

45. The method of claim 33, wherein the step of determining comprises the step of identifying any pathological condition of the tissue by detecting at least one of:

(a) a spectrum of light scattered by tissue in the region of interest;

(b) a spectrum of light emitted by tissue in the region of interest; and

(c) a spectrum of light absorbed by tissue in the region of interest.

46. The method of claim 33, wherein the light directed at the region of interest comprises light in a predefined waveband, and wherein the step of determining comprises the step of detecting an absorption spectrum of tissue in the region of interest when exposed to the light in the predefined waveband, to identify any pathological condition of the tissue.

48. The method of claim 33, wherein the step of rendering therapy comprises the step of delivering the light to the region of interest with a pixel-by-pixel resolution based upon the image of the region of interest.

49. The method of claim 33, further comprising the step of using light to render therapy to the region of interest and to monitor a condition of the region of interest as a result of rendering therapy thereto.

50. The method of claim 33, further comprising the step of endoscopically advancing a distal end of the light guide to the region of interest in the patient.

51. The method of claim 33, wherein the step of imaging the region of interest includes the step of more definitively determining a boundary of the region of interest.

52. The method of claim 33, wherein the step of determining comprises the step of performing an optical coherence tomography and reflectometry analysis of the region of interest.

53. The method of claim 33, wherein the step of determining comprises the step of performing at least one of a laser induced fluorescence analysis, a fluorescence lifetime analysis, an elastic scattering spectroscopy analysis, an optically stimulated vibro-acoustography analysis, a Raman spectroscopy analysis, and detecting chemi-luminescence, of the region of interest.

54. The method of claim 33, further comprising the step of carrying out steps (a)-(e) using a plurality of integral light guides arranged in an array.

55. The method of claim 33, further comprising the step of retrofitting an existing rigid endoscope system with the integral light guide system prior to the step of scanning the region of interest.

56. The method of claim 33, further comprising the step of retrofitting at least one of an existing semi-flexible relay system formed as a rod and a flexible optical fiber with the integral light guide system prior to the step of scanning the region of interest.

57. The method of claim 33, further comprising the step of illuminating and imaging the region of interest while simultaneously rendering said at least one other substantive function.

58. The method of claim 33, further comprising the step of imaging the region of interest in a frame-sequential manner.

59. The method of claim 33, further comprising the step of employing a frame sequence for alternately:

(a) imaging the region of interest during one frame of the frame sequence; and

(b) rendering said at least one other substantive function to the region of interest in a next frame of the frame sequence.

60. The method of claim 33, further comprising the step of enabling a user to employ a touch-sensitive display in controlling the integral light guide system.

61. The method of claim 33, further comprising the step of employing an audio enhancement to convey information to a user during the step of scanning of the region of interest.

62. The method of claim 33, wherein the step of imaging the region of interest comprises the step of enabling a user to visualize the region of interest as a quasi-stereo image on a stereo display.

63. The method of claim 33, further comprising the step of stabilizing the integral light guide system during the step of scanning.

64. The method of claim 33, further comprising the step of electronically stabilizing the region of interest during the step of imaging.

66. The method of claim 33, wherein the step of imaging includes the step of zooming an image in real-time.

67. The method of claim 33, further comprising the step of changing a resolution and a field of view dynamically, to enable zooming and dynamic magnification of the field of view when imaging the region of interest.

39. The method of claim 39, further comprising the step of mounting the lens at a distal end of the light guide.

40. The method of claim 40, wherein the lens is of sufficient mass that as the light guide moves, the lens is rotated about a center of the lens, but otherwise remains generally fixed.

47. The method of claim 47, wherein the step of detecting the absorption spectrum includes the step of mapping at least one of an absorption ratio, an emitted fluorescence ratio, and a phosphorescence ratio for the tissue to identify any pathological condition of the tissue.

65. The method of claim 65, wherein the step of electronically stabilizing comprises the step of freezing an image of the region of interest on a display, and processing the signals produced by scanning to maintain a boundary of the region of interest stable on the display.

68. Apparatus for automatically scanning a region of interest within a patient'"'"'s body, comprising:

(a) a light source;

(b) a light guide that is optically coupled to the light source and having a proximal end and a distal end, said light guide being adapted to convey light emitted by the light source from the proximal end of the light guide along a single light path to a region of interest within a patient'"'"'s body; and

(c) a scanning actuator that is disposed adjacent to the distal end of the light guide, said scanning actuator being coupled to the light guide and adapted to cause the distal end of the light guide to move about so that light conveyed through the light guide produces a scanning pattern on a region of interest, illuminating a region of interest a pixel at a time.

69. The apparatus of claim 69, wherein the scanning actuator comprises a pair of electromechanical actuators that respectively move the distal end of the light guide in substantially transverse directions.

70. The apparatus of claim 69, wherein the scanning actuator comprises a piezoceramic actuator that is energized at a harmonic of a resonant frequency of the distal end of the light guide, causing the light guide to oscillate.

71. The apparatus of claim 69, wherein the light guide comprises an optical fiber, and wherein the distal end of the optical fiber is tapered to a substantially smaller cross-sectional size than a more proximal portion of the optical fiber.

72. The apparatus of claim 69, further comprising at least one lens adapted to be disposed between the distal end of the light guide and a region of interest, said at least one lens being adapted to focus the light produced by the at least one light source onto a region of interest.

74. The apparatus of claim 69, wherein the light guide comprises a thin film optical waveguide disposed at the distal end of the light guide so that the light conveyed through the light guide passes through the thin film optical waveguide and is thus adapted to be directed onto a region of interest.

77. The apparatus of claim 69, further comprising a light detector adapted to receive light from the region of interest.

73. The apparatus of claim 73, wherein said at least one lens comprises a lens mounted at the distal end of the light guide, said scanning actuator being adapted to drive the distal end of the light guide in a resonance mode to scan a region of interest, said lens that is mounted at the distal end of the light guide having sufficient mass so that the lens generally rotates as the light guide moves to change a direction in which light is emitted, when scanning a region of interest.

75. The apparatus of claim 75, wherein the scanning actuator is disposed adjacent to the thin film optical waveguide and moves the thin film optical waveguide in the scanning pattern.

76. The apparatus of claim 75, wherein the thin film optical waveguide has a cross-sectional size less than 0.01 mm.

78. A method for automatically scanning a region of interest in a patient'"'"'s body, comprising the steps of:

(a) conveying light from a source along a single path through a light guide having a distal end that is disposed adjacent to the region of interest;

(b) automatically moving the distal end of the light guide in a desired scanning pattern in response to a scanning signal; and

(c) scanning the region of interest with light directed at the region of interest through the distal end of the light, directing the light at the region of interest in said scanning pattern, to illuminate the region of interest a pixel at a time, wherein the step of scanning comprises the step of driving a distal end of the light guide into a resonance movement mode.

79. The method of claim 79, wherein the step of scanning comprises the step of causing the distal end of the light guide to move so that the light emitted from the light guide scans over the region of interest in two generally orthogonal directions.

80. The method of claim 79, wherein the step of scanning comprises the step of causing the light guide to move so that the light emitted from the light guide scans over the region of interest in a helical arc.

81. The method of claim 79, wherein the step of scanning comprises the step of causing the light guide to move so that the light emitted from the light guide scans the region of interest in one of:

(a) generally concentric circles of different radii; and

(b) a propeller scan mode.

82. The method of claim 79, further comprising the step of mounting a lens at a distal end of the light guide.

84. The method of claim 79, wherein a distal end of the light guide comprises a thin film optical waveguide, said step of scanning comprising the step of causing a distal end of the thin film optical waveguide to move so that light emitted thereby is scanned over the region of interest in the desired scanning pattern.

85. The method of claim 79, wherein the step of scanning comprises the step of driving a distal end of the light guide into a resonance movement mode.

86. The method of claim 79, further comprising the step of detecting light from the region of interest to produce a signal used for imaging the region of interest.

83. The method of claim 83, wherein the lens is of sufficient mass that as the light guide moves, the lens is rotated.