Tethered capsule endoscope for Barrett's Esophagus screening

• US 7,530,948 B2
• Filed: 02/28/2005
• Issued: 05/12/2009
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Seibel, Eric J., Johnston, Richard S., Kimmey, Michael
• Primary Examiner(s): Leubecker; John P
• Application Number:
  US11/069,826
• Publication Number:
  US 20060195014A1
• Time in Patent Office: 1,534 Days
• Field of Search: 600/178, 600/173, 600/182, 600/176, 600/177, 600/129, 600476-478
• US Class Current: 600/178
• CPC Class Codes: A61B 1/000094 extracting biological structures
• CPC Class Codes: A61B 1/00055 for alerting the user
• CPC Class Codes: A61B 1/0008 characterised by distal tip features
• CPC Class Codes: A61B 1/00087 Tools A61B17/00234 takes precedence
• CPC Class Codes: A61B 1/00097 Sensors
• CPC Class Codes: A61B 1/00148 using anchoring means
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/015 Control of fluid supply or evacuation
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 1/043 for fluorescence imaging
• CPC Class Codes: A61B 1/0638 providing two or more wavelengths
• CPC Class Codes: A61B 1/0661 Endoscope light sources
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 1/2733 Oesophagoscopes
• 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 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14556 by fluorescence A61B5/14555 takes precedence
• CPC Class Codes: A61B 5/4233 : oesophagus
• CPC Class Codes: A61N 2005/0609 : Stomach and/or esophagus
• CPC Class Codes: A61N 5/0603 : for treatment of body cavities
• CPC Class Codes: A61N 5/062 : Photodynamic therapy, i.e. excitation of an agent

Abstract

A capsule is coupled to a tether that is manipulated to position the capsule and a scanner included within the capsule at a desired location within a lumen in a patient'"'"'s body. Images produced by the scanner can be used to detect Barrett'"'"'s Esophagus (BE) and early (asymptomatic) esophageal cancer after the capsule is swallowed and positioned with the tether to enable the scanner in the capsule to scan a region of the esophagus above the stomach to detect a characteristic dark pink color indicative of BE. The scanner moves in a desired pattern to illuminate a portion of the inner surface. Light from the inner surface is then received by detectors in the capsule, or conveyed externally through a waveguide to external detectors. Electrical signals are applied to energize an actuator that moves the scanner. The capsule can also be used for diagnostic and/or therapeutic purposes in other lumens.

Claims

1. Apparatus for imaging an inner surface of a lumen in a body, comprising:

(a) a capsule housing that is sized to readily pass through the lumen, the capsule housing having at least an imaging portion that is optically transparent;

(b) a light source;

(c) a scanner disposed within the capsule housing and coupled to the light source, the scanner having an actuator that drives the scanner to scan an inner surface of a lumen in a body in a desired scanning pattern with a beam of light from the scanner;

(d) at least one light sensor that responds to light that has been reflected from an inner surface of a lumen, producing an electrical signal that is indicative of an intensity of the light;

(e) an optical system that focuses the light emitted from the scanner onto a portion of an inner surface of a lumen in a body; and

(f) a flexible tether that is connected to the capsule housing and which extends proximally through a lumen to enable a force to be applied to the capsule housing to control a movement of the capsule housing, wherein the flexible tether is of sufficient strength to retract the capsule housing from the lumen but is too flexible to push the capsule housing distally through the lumen.

2. The apparatus of claim 1, wherein the at least one light sensor is disposed external to the capsule housing, the light reflected from an inner surface of a lumen being conveyed through an optically transmissive channel included within the tether to the at least one light sensor.

3. The apparatus of claim 2, wherein the optically transmissive channel comprises one of:

(a) a core of an optical fiber that comprises the tether;

(b) a core of an optical fiber that also conveys light from the light source through the tether and into the capsule housing; and

(c) a cladding of an optical fiber that comprises the tether.

4. The apparatus of claim 1, wherein the at least one light sensor is disposed within the capsule housing, the light reflected from an inner surface of a lumen being received by the at least one light sensor, causing a corresponding electrical signal to be produced.

5. The apparatus of claim 4, wherein the tether includes at least one electrical lead that is coupled to the light sensor and conveys the electrical signal from the at least one light sensor to a location that is outside of a lumen in a body.

6. The apparatus of claim 1, wherein the scanner includes a scanning mirror that is driven by the actuator to reflect the light produced by the light source, in the desired scanning pattern.

7. The apparatus of claim 1, wherein the scanner comprises a waveguide that is driven to move by the actuator, so that the waveguide emits light from a distal end of the waveguide, to scan in the desired pattern.

8. The apparatus of claim 1, farther comprising a pressure sensor disposed on the capsule housing for monitoring a pressure applied to the capsule, the pressure sensor producing a pressure signal indicative of the pressure applied to the capsule housing.

9. The apparatus of claim 1, further comprising a location sensor for monitoring a location of the capsule housing within a lumen relative to a reference point.

10. The apparatus of claim 1, further comprising a chemical sensor for monitoring at least one chemical parameter from within a lumen of a body.

11. The apparatus of claim 1, further comprising means for performing a biopsy to take a tissue sample at a desired site within a lumen of a body.

12. The apparatus of claim 1, further comprising at least one electrical contact disposed on an exterior of the capsule housing, to stimulate a muscle in a wall of a lumen of a body in which the capsule housing is disposed, to promote peristalsis that moves the capsule housing through a lumen.

13. The apparatus of claim 1, wherein the tether includes a plurality of scale markings that serve to enable a user to measure a distance traveled by the capsule housing into a lumen of a body.

14. The apparatus of claim 1, further comprising a rotary component engaged by the tether that is rotated as the capsule housing moves through a lumen of a body, the rotary component being used to provide an indication of a distance traveled by the capsule housing into a lumen.

15. The apparatus of claim 14, wherein a lumen comprises an esophagus of a body, farther comprising a bite bar that is adapted to be disposed in a mouth of a patient to support the rotary component, so as to ensure a reproducible tracking of the distance through which the capsule housing moves within an esophagus.

16. The apparatus of claim 14, farther comprising a selectively releasable joint for connecting to the tether and disposed at least at one of:

(a) adjacent to the capsule housing; and

(b) adjacent to the bite bar.

17. The apparatus of claim 1, wherein the optics system includes at least one reflective surface for directing the light emitted from the scanner laterally to a side of the capsule is housing.

18. The apparatus of claim 1, wherein the optical system includes at least one lens disposed between the scanner and the imaging portion of the capsule.

19. The apparatus of claim 1, wherein the imaging portion of the capsule is disposed at a distal end of the capsule housing, the tether being connected to a proximal end of the capsule housing.

20. The apparatus of claim 1, wherein the optical system includes at least one filter that is disposed so as to filter light that is one of:

(a) produced by the scanner and directed to an internal surface of a lumen; and

(b) reflected from an internal surface of a lumen before the light is sensed by the at least one light sensor.

21. The apparatus of claim 1, wherein the scanner comprises one of:

(a) a single mode optical fiber;

(b) a dual cladding optical fiber;

(c) a single mode optical fiber used for conveying light from the light source, and at least one multimode collection optical fiber for conveying light reflected from an inner surface of a lumen to the at least one light sensor; and

(d) a waveguide comprising a microelectromechanical system (MEMS) device.

22. The apparatus of claim 1, wherein the scanner comprises one of a waveguide and an optical fiber that is driven by the actuator to move at about a resonant frequency when scanning in the desired pattern.

23. The apparatus of claim 22, further comprising a feedback sensor for controlling a movement of said one of the waveguide and the optical fiber, so as to substantially reduce any distortion in an image produced by scanning with the light beam produced by said one of the waveguide and the optical fiber.

24. The apparatus of claim 1, wherein the actuator comprises an electromechanical actuator that produces a driving force in a plurality of orthogonal directions, to achieve the desired pattern for scanning an internal surface of a lumen in a body.

25. The apparatus of claim 1, wherein the at least one light sensor comprises a plurality of light sensors, including light sensors that are responsive to at least one of:

(a) light of different spectral wavebands; and

(b) polarized light.

26. The apparatus of claim 1, wherein the optical system directs the light emitted by the scanner through the imaging portion of the capsule housing, so that the desired scanning pattern illuminates an interior surface of a lumen over substantially an entire 360 degree arc.

27. The apparatus of claim 1, further comprising a plurality of scanners disposed within the capsule housing, each scanner including a separate actuator and being configured to scan a different part of an inner surface of a lumen in a body.

28. The apparatus of claim 27, wherein the plurality of scanners are configured to at least:

(a) increase a field of view compared to a field of view provided by a single scanner;

(b) scan an inner surface of a lumen from opposite ends of the capsule housing;

(c) provide a stereo scan image of an inner surface of a lumen;

(d) perform a diagnostic scan of an inner surface of a lumen using light of a predefined waveband;

(e) provide a therapeutic scan of an inner surface of a lumen using light from at least one of the plurality of scanners;

(f) monitor a state of therapy being applied within a lumen; and

(g) provide illumination used to measure distance between one scanner and an inner surface of a lumen.

29. The apparatus of claim 27, wherein the plurality of scanners are spaced apart in an array within the capsule housing, and wherein the optical system directs the light emitted from each scanner to different parts of an inner surface of a lumen.

30. The apparatus of claim 1, wherein the capsule housing is sized and configured to be swallowed by a patient with the tether connected thereto.

31. The apparatus of claim 1, further comprising a data recording medium that receives an electrical signal from the at least one light sensor and stores data corresponding to the electrical signal produced by the at least one light sensor.

32. The apparatus of claim 31, wherein the data represent a plurality of image frames that are readily combined to provide at least one continuous two-dimensional image of an inner surface of a lumen in a body.

33. The apparatus of claim 1, further comprising a spectral analyzer that analyzes an electrical signal produced by the at least one light sensor in a desired range that is selected from a waveband range extending from an ultraviolet to an infrared waveband.

34. The apparatus of claim 1, further comprising an inflatable balloon coupled to the capsule, the balloon being inflated to at least one of:

(a) enable peristaltic advancement of the balloon with the capsule through a lumen in a body by forces applied by a lumen on the balloon;

(b) convey a fluid pressure from a wall of a lumen in which the balloon is disposed, to a pressure sensor that enables a pressure exerted thereby on the balloon to be monitored;

(c) to enlarge a cross-sectional size of the balloon and the capsule housing in combination, thereby preventing further movement of the capsule housing through a cross-sectional passage in a body that is smaller than a cross-sectional size of the balloon when the balloon is at least partially inflated; and

(d) generally center the capsule housing within a lumen of a body.

35. The apparatus of claim 1, further comprising a disconnect that is selectively actuatable to release the capsule housing from the tether.

36. A capsular system for scanning an inner surface of a lumen in a body, comprising:

(a) a housing defining a capsule that is sized to fit within a lumen in a body and to be readily advanced therethrough;

(b) a flexible tether connected to the capsule and having a length sufficient to extend proximally external of a lumen in which the housing is disposed, wherein the flexible tether is of sufficient strength to retract the capsule from the lumen but is too flexible to push the capsule distally through the lumen;

(c) a light source that produces light for illuminating an inner surface of a lumen in which the housing is disposed;

(d) a scanner having an actuator that drives the scanner to scan an inner surface of a lumen in a body in a desired scanning pattern with a beam of light from the scanner; and

(e) a light sensor that receives light reflected from a region of an inner surface of a lumen, producing a signal indicative of an intensity thereof.

37. The capsular system of claim 36, wherein the housing is shaped to facilitate swallowing by a patient down an esophagus, the scanner being used to scan an inner surface of an esophagus to detect a visual change associated with Barrett'"'"'s Esophagus.

38. The capsular system of claim 36, further comprising a location sensor disposed within the housing to determine a relative position of the housing within a lumen of a body, including a distance along a lumen traversed by the housing relative to a reference point.

39. The capsular system of claim 36, wherein the scanner comprises one of a waveguide and an optical fiber, a distal end of the waveguide being driven by the actuator to move and emit a beam of light in the desired pattern.

40. The capsular system of claim 36, wherein the scanner further includes an optical system having at least one lens disposed within the housing to modify the light emitted from the distal end of the waveguide so as to facilitate scanning a desired region of an inner surface of a lumen in which the housing is disposed.

41. The capsular system of claim 40, further comprising a plurality of scanners disposed within the housing, each scanner being directed to scan a different portion of an inner surface of a lumen in which the housing is disposed.

42. The capsular system of claim 36, wherein the light sensor is responsive to at least one of:

(a) white light;

(b) visible light within a specific waveband;

(c) non-visible light within a specific waveband; and

(d) polarized light.

43. A method for scanning an inner surface of a lumen in a body, comprising the steps of:

(a) introducing a capsule that includes a scanner into the lumen, the capsule further including a tether coupled to the capsule;

(b) enabling the capsule to advance through the lumen, with a proximal end of the tether remaining outside the lumen;

(c) controlling a disposition of the capsule within the lumen by exerting a force on the tether;

(d) producing an image of the inner surface of the lumen with the scanner; and

(e) reproducibly tracking a distance through which the capsule moves within the lumen.

44. The method of claim 43, wherein the step of controlling a disposition comprises the step of using the tether to position the capsule to scan a desired region in the lumen with the scanner.

45. The method of claim 43, wherein the step of enabling the capsule to advance comprises the step of enabling a peristaltic movement of muscle tissue comprising walls of the lumen to move the capsule through the lumen.

46. The method of claim 45, wherein the step of enabling the capsule to advance further comprises the step of inflating a balloon around the capsule so that the muscle tissue interacts with the balloon to advance the capsule through the lumen.

47. The method of claim 43, further comprising the step of exciting the muscle tissue with an electrical current applied through a conductor disposed on at least one of the capsule and the tether, the electrical current causing a peristaltic movement of muscle tissue so as to at least one of:

(a) advance the capsule through the lumen;

(b) change a portion of the inner surface of the lumen that is imaged with the scanner by causing relative movement between the capsule and the inner surface; and

(c) diagnose an abnormal medical condition of the inner surface of the lumen by detecting a portion of the inner surface that is substantially less contractile in response to the electrical current, compared to normal tissue comprising the inner surface.

48. The method of claim 43, wherein the lumen comprises an esophagus of a patient, and wherein the step of introducing the capsule comprises the step of enabling the patient to swallow the capsule with a liquid.

49. The method of claim 43, further comprising the step of analyzing the image with a spectral analyzer that responds to a range of wavelengths from an ultraviolet waveband to an infrared waveband.

50. The method of claim 43, further comprising the step of determining a position of the capsule within the lumen by at least one of:

(a) sensing a signal indicative of the position of the capsule within the lumen;

(b) measuring a length of the tether that has been advanced into the lumen; and

(c) determining the position based upon a content of the image that is produced that indicates one of an anatomical feature and a medical condition within the lumen.

51. The method of claim 43, further comprising the step of administering a therapy to the lumen using the capsule.

52. The method of claim 43, further comprising the steps of:

(a) producing a plurality of overlapping images with the scanner; and

(b) combining the plurality of overlapping images to produce a composite image of a substantially larger area than is encompassed by a single image.

53. The method of claim 43, further comprising the step of employing a plurality of scanners disposed in the capsule to achieve at least one of the following results:

(a) scanning different regions of the lumen with each of the plurality of scanners;

(b) producing a stereoscopic view of an inner surface of the lumen;

(c) implementing a diagnostic function by detecting light in different wavebands received from the inner surface of the lumen;

(d) rendering a therapeutic function;

(e) monitoring the lumen for at least one of controlling a therapy being rendered, and assessing a condition of the lumen after the therapy has been administered; and

(f) providing additional illumination for imaging the interior surface of the lumen.

54. The method of claim 43, further comprising the step of employing a sensor associated with the capsule for monitoring a parameter related to the lumen.

55. The method of claim 54, wherein the parameter comprises one of:

(a) a chemical level;

(b) a pressure exerted by walls of the lumen; and

(c) a temperature.

56. The method of claim 43, further comprising the step of enabling a user to enable the capsule to pass through the lumen without further constraint from the tether by one of the steps of:

(a) releasing a proximal end of the tether so that the tether and the capsule move through the lumen; and

(b) releasing the capsule from the tether so that the capsule can move through the lumen.

57. The method of claim 43, further comprising the step of retrieving the capsule by one of the steps of:

(a) enabling the capsule to pass through the lumen and be expelled from the body; and

(b) withdrawing the capsule from the lumen by applying force to the tether.

58. The method of claim 43, further comprising the step of enabling a user to rotate the capsule by rotating the tether connected thereto.

59. An imaging probe for producing images of a surface within a body lumen, comprising:

(a) a capsule disposed at a distal end of the imaging probe, said capsule being sized to enable the capsule to be readily introduced into a body lumen and including an imaging device for producing a signal that is usable to display an image of an inner surface within a body lumen;

(b) a tether having a proximal end, and a distal end that is coupled to the capsule, said tether being flexible and substantially smaller in diameter than the capsule and being employed for moving the capsule and for conveying signals produced by the imaging device for use in displaying an image of an inner surface of a body lumen; and

(c) means for reproducibly tracking a distance through which the capsule moves within the body lumen.

60. The imaging probe of claim 59, wherein the tether conveys at least one signal from the capsule toward the proximal end of the tether, wherein the at least one signal is selected from the group consisting of an electrical signal, and an optical signal from the capsule.

61. The imaging probe of claim 59, wherein the tether conveys at least one signal from the proximal end of the tether to the capsule, wherein the at least one signal is selected from the group consisting of an electrical signal, and an optical signal.

62. The imaging probe of claim 59, wherein the capsule is sized and configured to enable it to be readily swallowed down an esophagus of a patient, to enable imaging of a wall of an esophagus.

63. The imaging probe of claim 62, wherein the tether is sufficiently small in cross-sectional size and sufficiently flexible to enable it to readily follow the capsule down an esophagus of a patient when the capsule is swallowed.

64. The imaging probe of claim 59, wherein the signal produced by the imaging device in the capsule that enables display of an image of an inner surface of a body lumen is one of an electrical signal conveyed by a conductor disposed in the tether and an optical signal that is conveyed through an optical fiber in the tether, for use in externally displaying the image.

65. A capsular system for scanning an inner surface within a body lumen, comprising:

(a) a capsule disposed at a distal end of the capsular system, said capsule being sized to enable the capsule to be readily introduced into a body lumen and including a scanning device for producing a signal that is usable to display an image of an inner surface within the body lumen, said scanning device being coupled to a light source and being configured to scan the inner surface within the body lumen in a desired scanning pattern with a beam of light; and

(b) a tether having a proximal end, and a distal end that is coupled to the capsule, said tether being flexible and substantially smaller in diameter than the capsule and being employed for moving the capsule and for conveying signals produced by the scanning device, for use in displaying an image of the inner surface of the body lumen.

66. Apparatus for imaging an inner surface of a lumen within a body, comprising:

(a) a capsule housing that is sized to readily pass through the lumen, at least a portion of the capsule housing being optically transparent;

(b) a light source;

(c) a scanner disposed within the capsule housing and coupled to the light source, the scanner having an actuator that drives the scanner to scan an inner surface of a lumen in a body with a beam of light that moves in a desired scanning pattern;

(d) at least one light sensor that responds to light that has been reflected from an inner surface of a lumen, producing an electrical signal that is indicative of an intensity of the light;

(e) an optical system that focuses the light used for scanning in the desired scanning pattern onto a portion of an inner surface of a lumen;

(f) a tether that is connected to the capsule housing and which is configured to extend proximally through a lumen to enable a force to be applied to the capsule housing to control a movement of the capsule housing; and

(g) an inflatable balloon coupled to the capsule, the balloon being inflated to at least one of;

(i) enable peristaltic advancement of the balloon with the capsule through a lumen in a body by forces applied by the lumen on the balloon when the balloon is at least partially inflated;

(ii) convey a fluid pressure from a wall of a lumen in which the balloon is disposed, to a pressure sensor that enables a pressure exerted thereby on the balloon to be monitored;

(iii) prevent further movement of the capsule housing through a lumen having a cross-sectional size that is smaller than that of the balloon when the balloon is at least partially inflated; and

(iv) generally center the capsule housing within a lumen of a body.

67. A method for scanning an inner surface of a lumen in a body, comprising the steps of:

(a) introducing a capsule that includes a scanner into the lumen, the capsule being coupled to a tether;

(b) enabling the capsule to advance through the lumen, with a proximal end of the tether remaining outside the lumen;

(c) controlling a disposition of the capsule within the lumen by exerting a force on the tether;

(d) producing an image of the inner surface of the lumen with the scanner; and

(e) enabling a user to selectively allow the capsule to pass through the lumen without further constraint from the tether by carrying out one of the steps of;

(i) releasing the proximal end of the tether so that both the tether and the capsule can move through the lumen; and

(ii) releasing the capsule from the tether so that the capsule can move through the lumen free of the tether.