Fiber optic imaging endoscope interferometer with at least one faraday rotator

• US 6,501,551 B1
• Filed: 10/05/1999
• Issued: 12/31/2002
• Est. Priority Date: 04/29/1991
• Status: Expired due to Fees

• Current Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Boppart, Stephen A., Bouma, Brett E., Fujimoto, James G., Tearney, Guillermo, Swanson, Eric A., Brezinski, Mark
• Primary Examiner(s): Turner, Samuel A.
• Application Number:
  US09/414,293
• Time in Patent Office: 1,183 Days
• Field of Search: 356/477, 356/479, 356/497, 250/227.19, 250/227.27, 385/14, 385/117, 600/101, 600/104, 600/108, 600/160, 600/425
• US Class Current: 356/477
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00183 for variable viewing angles
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 3/1005 for measuring distances inside the eye, e.g. thickness of the cornea A61B3/11 takes precedence
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 5/0064 Body surface scanning
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/445 Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G01B 11/12 internal diameters
• CPC Class Codes: G01B 11/2441 using interferometry
• CPC Class Codes: G01B 2290/65 Spatial scanning object beam
• CPC Class Codes: G01B 2290/70 Using polarization in the interferometer
• CPC Class Codes: G01B 9/02002 using two or more frequencies
• CPC Class Codes: G01B 9/02004 using frequency scans
• CPC Class Codes: G01B 9/02007 : Two or more frequencies or sources used for interferometric measurement using only beat G01B9/02003
• CPC Class Codes: G01B 9/0201 : using temporal phase variation
• CPC Class Codes: G01B 9/0205 : of probe head
• CPC Class Codes: G01B 9/02091 : Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G01J 1/00 : Photometry, e.g. photographic exposure meter spectrophotometry G01J3/00; specially adapted for radiation pyrometry G01J5/00 ; exposure meters built in cameras G03B17/06
• CPC Class Codes: G01N 21/4795 : spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G11B 2007/0013 : for carriers having multiple discrete layers
• CPC Class Codes: G11B 7/005 : Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/127 : Lasers; Multiple laser arrays lasers per se H01S
• CPC Class Codes: G11B 7/24 : Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007
• CPC Class Codes: H01S 5/141 : using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence

Abstract

An imaging system for performing optical coherence tomography includes an optical radiation source; a reference optical reflector; a first optical path leading to the reference optical reflector; and a second optical path coupled to an endoscopic unit. The endoscopic unit preferably includes an elongated housing defining a bore; a rotatable single mode optical fiber having a proximal end and a distal end positioned within and extending the length of the bore of the elongated housing; and an optical system coupled to the distal end of the rotatable single mode optical fiber, positioned to transmit the optical radiation from the single mode optical fiber to the structure and to transmit reflected optical radiation from the structure to the single mode optical fiber. The system further includes a beam divider dividing the optical radiation from the optical radiation source along the first optical path to the reflector and along the second optical path; and a detector positioned to receive reflected optical radiation from the reflector transmitted along the first optical path and reflected optical radiation transmitted from the structure along the second optical path. The detector generates a signal in response to the reflected optical radiation from the reference reflector and the reflected optical radiation from the structure, and a processor generating a image of the structure in response to the signal from the detector. The system provides both rotational and longitudinal scanning of an image.

Claims

1. An apparatus for performing imaging of a structure in situ comprising:

a light source;

a photodetector;

a processor in electrical communication with said detector;

an optical probe unit comprising a housing defining a channel, said housing having at least a portion which is at least partially transparent to radiation from said light source;

a beam director located within said housing and positioned to direct radiation to and from said structure in situ through said at least partially transparent portion;

an interferometer optically coupled to said light source, said optical probe unit, and said photodetector; and

,

a Faraday rotator positioned to direct radiation from said interferometer to said photodetector,

wherein said photodetector generates a signal in response to radiation altered by said structure in situ; and

wherein said processor generates an image of said structure in situ in response to said signal from said photodetector.

2. The apparatus of claim 1, wherein said Faraday rotator is a Faraday circulator comprising multiple ports.

3. The apparatus of claim 1, further comprising a fiber optic coupler in optical communication with said photodetector.

4. The apparatus of claim 1, wherein said photodetector further comprises a balanced receiver.

5. The apparatus of claim 1, wherein said Faraday rotator comprises a Faraday mirror located adjacent the distal end of the housing.

6. The apparatus of claim 1, where said beam director is capable of rotating.

7. The apparatus of claim 6, further comprising a flexible, rotatable shaft coupling the beam director to a drive mechanism.

8. The apparatus of claim 1, further comprising an optical fiber positioned to direct light from said interferometer to said beam director, said optical fiber being coupled to said interferometer through an interface.

9. The apparatus of claim 8, wherein said interface is a fluid medium.

10. The apparatus of claim 1, further comprising a laser scalpel optically coupled to said beam director by an optical coupler.

11. The apparatus of claim 10, wherein said optical coupler is a switch.

12. The apparatus of claim 1, further comprising a scanning mechanism for causing said beam director to scan both rotationally and longitudinally to produce a spiral scan pattern.

13. The apparatus of claim 1, further comprising a scanning mechanism for causing said beam director to scan back and forth through an angle or arc.

14. The apparatus of claim 1, further comprising a scanning mechanism for causing said beam director to scan longitudinally.

15. The apparatus of claim 1, further comprising a scanning mechanism for causing said beam director to scan in a x-y raster fashion.

16. The apparatus of claim 1, further comprising a scanning mechanism for causing said beam director to scan in a pyramidal fashion.

17. The apparatus of claim 1, wherein the probe unit is coupled to an atherectomy device.

18. The apparatus of claim 1, wherein the probe unit further comprises a trocar.

19. The apparatus of claim 1, wherein said housing further comprises an irrigation port positioned to deliver fluid to said partially transparent portion.

20. The apparatus of claim 1, wherein said housing further comprises an inflatable element supporting a stent.

21. The apparatus of claim 20, wherein said structure and stent are imaged.

22. The apparatus of claim 1, wherein said probe unit further comprises a guidewire.

23. The apparatus of claim 1, wherein said beam director is capable of moving within said housing with a predetermined motion.