Methods and apparatus for optical coherence tomography scanning

• US 20060187462A1
• Filed: 01/20/2006
• Published: 08/24/2006
• Est. Priority Date: 01/21/2005
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Wotjkowski, Maciej, Huber, Robert, Ko, Tony, Fujimoto, James, Srinivasan, Vivek
• Granted Patent: US 7,884,945 B2
• Time in Patent Office: Days
• US Class Current: 356/479
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/4842 Monitoring progression or stage of a disease
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

In one aspect, the invention relates to a method of acquiring optical coherence tomographic data from a sample. The method includes the steps of scanning a first location on the sample to obtain a first set of optical coherence tomographic data, scanning a second location on the sample to obtain a second set of optical coherence tomographic data, and defining a fiducial position relative to a location on the sample using one of the two sets of optical coherence tomographic data. In one embodiment, the first set of optical coherence tomographic data is survey data. However, in another embodiment the first set of optical coherence tomographic data is sample measurement data.

Claims

1. A method of acquiring optical coherence tomographic data from a sample, the method comprising the steps of

scanning a first location on the sample to obtain a first set of optical coherence tomographic data;

scanning a second location on the sample to obtain a second set of optical coherence tomographic data; and

defining a fiducial position relative to a location on the sample using one of the two sets of optical coherence tomographic data.

2. The method of claim 1 wherein the first set of optical coherence tomographic data contains data from three axial scans having locations in the transverse plane that are non-collinear.

3. The method of claim 1 further comprising the step of transforming three dimensional data to two dimensional data to identify a landmark on the sample.

4. The method of claim 1 wherein the sample is a human eye.

5. The method of claim 4 wherein the fiducial position includes a portion of at least one of an optic nerve head or an optic disk.

6. The method of claim 1 wherein the first scan is a survey scan.

7. The method of claim 1 wherein the first scan is a measurement scan.

8. The method of claim 1 further comprising the step of tracking changes in the fiducial position using the first scan or the second scan.

9. The method of claim 1 wherein the first location and the second location are substantially the same.

10. A method of acquiring optical coherence tomographic data from a sample, the method comprising the steps of

collecting optical coherence tomographic survey data from a first location on the sample;

defining a first position relative to the first location using the optical coherence tomographic survey data; and

performing an optical coherence tomographic scan to obtain optical coherence tomographic measurement data from the sample in response to the first position.

11. The method of claim 10 wherein at least one of the first position, the first location on the sample and the second location on the sample are the same.

12. The method of claim 10 wherein the optical coherence tomographic data is obtained using a hand-held scanner.

13. The method of claim 10 wherein the optical coherence tomographic survey data is used to obtain OCT data which is registered with respect to features in a human eye.

14. A method of evaluating optical coherence tomography (OCT) data obtained from a sample having a landmark, the method comprising the steps of:

performing a first OCT scan of a region on the sample to generate a first data set, the first data set comprising positional information about the landmark; and

performing a second OCT scan using the positional information from the first scan.

15. The method of claim 14 wherein the first OCT scan is a survey scan and the second scan is a measurement scan.

16. The method of claim 15 further comprising the step of iteratively performing survey optical coherence tomographic scans of the first sample region prior to performing the measurement optical coherence tomographic scan.

17. A method of evaluating optical coherence tomography (OCT) data obtained from a sample having a landmark, the method comprising the steps of:

performing a first OCT scan of a location on the sample to generate a first survey data set, the first survey data set comprising first OCT scan positional information about the landmark; and

performing a second OCT scan using the first OCT positional information from the first OCT scan.

18. The method of claim 17 further comprising the steps of:

performing a third OCT scan of the sample to generate a second survey data set, the second survey data set comprising second OCT positional information about the landmark; and

comparing the first OCT scan positional information and the second OCT scan positional information to determine an amount of change in landmark position, the amount of change in landmark position indicative of an error level.

19. The method of claim 18 wherein the amount of change in landmark position is used to determine if an additional measurement OCT data acquisition scan is necessary.

20. The method of claim 18 further comprising the step of performing a fourth OCT scan if the error level exceeds a predetermined threshold.

21. A method of processing optical coherence tomography (OCT) data obtained for a sample, the method comprising the steps of:

performing a survey scan to obtain survey scan data;

performing an optical coherence tomography scan to obtain sample data;

analyzing the survey scan data to identify landmark region data; and

processing the sample data in response to the landmark region data.

22. The method of claim 21 further comprising the step of selecting a subset of data from the sample data for processing in response to the landmark region data.

23. The method of claim 21 further comprising the step of generating an image using the sample data.

24. The method of claim 21 further comprising the step of generating numerical measurements regarding portions of elements in the sample using the sample data.

25. The method of claim 24 wherein the elements are constituents of a human eye.

26. The method of claim 21 further comprising the step of correcting for movement artifacts using the survey scan data.

27. A method of monitoring disease progression in a human eye, the method comprising the steps of:

performing a survey scan to obtain survey scan data;

analyzing the survey scan data to identify a landmark region in the eye;

registering a portion of a region of affected tissue in the eye relative to the landmark region; and

monitoring changes to the region of affected tissue at different points in time.

28. The method of claim 27 wherein the region of affected tissue is selected from the group consisting of lens tissue, corneal tissue, retinal tissue, cardiac tissue and components thereof.

29. The method of claim 27 wherein the points in time correspond to a plurality of eye exams.

30. An optical coherence tomographic device for obtaining optical coherence tomographic data of a sample location, the device comprising:

means for performing a first optical coherence tomographic scan of a first sample location to obtain first optical coherence tomographic data;

means for defining a fiducial position relative to the first sample location in response to the first optical coherence tomographic data obtained from the first optical coherence tomographic scan; and

automated means for performing a second optical coherence tomographic scan to obtain second optical coherence tomographic data from the first sample location in response to the fiducial position from the first sample location.

31. The device of claim 30 further comprising means for performing a supplemental measurement scan in response to changes in the fiducial position.

32. An optical coherence tomographic device, the device comprising:

an opto-mechanical system adapted for beam steering and OCT scanning, and

a controller in communication with the opto-mechanical system,

wherein the controller causes the opto-mechanical system to perform a first optical coherence tomographic scan of a first sample location to obtain first optical coherence tomographic data;

wherein the controller defines a fiducial position with respect to the first sample location in response to the first optical coherence tomographic data obtained from the survey optical coherence tomographic scan; and

wherein the controller causes the OCT interferometer to perform a second optical coherence tomographic scan to obtain second optical coherence tomographic in response to the fiducial position in the first sample location.

33. The device of claim 32 wherein the controller further tracks changes in the fiducial position in the first sample location.

34. The device of claim 33 wherein the controller further causes the OCT interferometer to perform a supplemental measurement scan in response to changes in the fiducial position.

35. The device of claim 32 wherein the controller further causes the OCT interferometer to repeat the measurement OCT data acquisition scan if the quality of the measurement OCT data acquisition scan does not exceed a predetermined level of error.

36. The device of claim 32, wherein the opto-mechanical system comprises an interferometer sample arm such that a portion of the interferometer sample arm is handheld.

37. The device of claim 32 wherein a survey optical coherence tomographic scan location is initiated by the controller.

38. The device of claim 32 further comprising an optical fiber such that optical coherence tomography beam positioning is performed by actuating the optical fiber.

39. The device of claim 32 wherein the device is an ophthalmic device.

40. The device of claim 39 wherein a survey optical coherence tomographic scan location is determined by using a subject'"'"'s eye fixation.