Method and system for localizing a medical tool

• US 20050182316A1
• Filed: 07/29/2004
• Published: 08/18/2005
• Est. Priority Date: 08/29/2002
• Status: Abandoned Application

• Current Assignee: Computerized Medical Systems, Inc. (Elekta AB)
• Original Assignee: Computerized Medical Systems, Inc. (Elekta AB)
• Inventors: Alix, Christopher, Haken, Lippold, Burdette, Everette C.
• Application Number:
  US10/902,429
• Publication Number:
  US 20050182316A1
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 17/3403 Needle locating or guiding means guides for suture needles A61B17/0482; guiding or tracking by nuclear magnetic resonance G01R33/285
• CPC Class Codes: A61B 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2017/3413 guided by ultrasound
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61B 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2065 Tracking using image or pattern recognition
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2090/364 Correlation of different images or relation of image positions in respect to the body
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61B 2090/3945 Active visible markers, e.g. light emitting diodes
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• CPC Class Codes: A61B 8/0833 involving detecting or locating foreign bodies or organic structures
• CPC Class Codes: A61B 8/0841 for locating instruments
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/4254 using sensors mounted on the probe
• CPC Class Codes: A61N 5/10 X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy A61N5/01 takes precedence

Abstract

A method of localizing a medical tool, the method comprising: (1) generating an image of a reference target with a camera that is attached to a medical tool, wherein the reference target is remote from the medical tool and located in a room at a known position relative to a coordinate system; and (2) determining the position of the medical tool relative to the coordinate system at least partially on the basis of the generated image of the reference target. Examples of medical tools that can be localized in accordance with the present invention include medical imaging devices, surgical instruments, and bite blocks.

Claims

1. A method of localizing a medical imaging probe, the method comprising:

generating an image of a reference target with a camera that is attached to a medical imaging probe, wherein the reference target is remote from the probe and located in a room at a known position relative to a coordinate system; and

determining the position of the probe relative to the coordinate system at least partially on the basis of the generated image of the reference target.

2. The method of claim 1 wherein the determining step comprises determining, in substantially real-time, the position of the probe relative to the coordinate system at least partially on the basis of the generated image of the reference target.

3. The method of claim 2 wherein the reference target comprises at least one selected from the group consisting of a plurality of passive reflectors and a plurality of printed marks visible to the camera.

4. The method of claim 3 wherein the reference target comprises a plurality of printed marks arranged in a grid pattern.

5. The method of claim 4 wherein the grid pattern is a checkerboard pattern.

6. The method of claim 1 wherein the medical imaging probe is an ultrasound probe.

7. The method of claim 6 wherein the ultrasound probe is a freehand ultrasound probe.

8. The method of claim 6 further comprising:

generating at least one image of a patient'"'"'s region-of-interest (ROI) through use of the ultrasound probe; and

spatially registering the at least one generated ROI image relative to the coordinate system at least partially on the basis of the determined probe position.

9. The method of claim 8 wherein the ROI is a patient'"'"'s prostate.

10. A method of localizing a medical tool, the method comprising:

generating an image of a reference target with a camera that is attached to a medical tool, wherein the reference target is remote from the medical tool and located in a room at a known position relative to a coordinate system; and

determining the position of the medical tool relative to the coordinate system at least partially on the basis of the generated image of the reference target.

11. The method of claim 10 wherein the reference target comprises a plurality of identifiable marks thereon that are arranged in a known spatial relationship with respect to each other, and wherein the camera is attached to the medical tool at a position thereon having a known spatial relationship with respect to a point of interest on the medical tool.

12. The method of claim 11 wherein the medical tool is a medical imaging device.

13. The method of claim 12 wherein the medical imaging device is a freehand ultrasound probe.

14. The method of claim 11 wherein the medical tool is a surgical instrument.

15. The method of claim 11 wherein the medical tool is a bite block for use in treating head or neck lesions.

16. The method of claim 11 wherein the reference target is located in the room at a fixed position, and wherein the determining step comprises determining, in substantially real-time, the position of the medical tool relative to the coordinate system at least partially on the basis of the generated image of the reference target.

17. A system for localizing a medical imaging device, the system comprising:

a reference target having a known position in a fixed coordinate system;

a medical imaging device having a field of view and being configured to receive data from which a medical image of a patient within the device'"'"'s field of view is generated, the medical imaging device being remote from the reference target;

a camera attached to the medical imaging device for tracking the reference target and generating at least one image within which the reference target is depicted; and

a computer configured to (a) receive the camera image and (b) process the received camera image to determine the position of the medical imaging device'"'"'s field of view relative to the coordinate system in 3D coordinate space.

18. The system of claim 17 wherein the position of the medical imaging device'"'"'s field of view relative to the position of the camera on the medical imaging device is known and wherein the computer is further configured to (a) determine, in substantially real-time, the position of the camera in the coordinate system at least partially on the basis of the received camera image, and (b) determine, in substantially real-time, the position of the medical imaging device'"'"'s field of view at least partially on the basis of the determined camera position and the known position of the medical imaging device'"'"'s field of view relative to the position of the camera on the medical imaging device.

19. The system of claim 17 wherein the reference target comprises a plurality of identifiable marks thereon that are arranged in a known spatial relationship with respect to each other.

20. The system of claim 19 wherein the reference target comprises a plurality of passive reflectors.

21. The system of claim 19 wherein the reference target comprises a plurality of printed marks visible to the camera.

22. The system of claim 21 wherein the printed marks are arranged in a grid pattern.

23. The system of claim 21 wherein the grid pattern is a checkerboard pattern.

24. The system of claim 17 wherein the medical imaging device is a freehand ultrasound probe.

25. The system of claim 24 wherein the camera is attached to the freehand ultrasound probe in close proximity to the probe'"'"'s field of view.

26. The system of claim 24 wherein the freehand ultrasound probe is used to generate ultrasound images of an internal organ of a patient.

27. The system of claim 26 wherein the internal organ is the prostate.

28. The system of claim 26 wherein the origin of the fixed coordinate system is a machine isocenter of a linear accelerator (LINAC).

29. The system of claim 28 further comprising a LINAC for targeting a beam of radiation to a tumor on the patient'"'"'s internal organ, wherein the LINAC includes a gantry, and wherein the reference target is located at a known position relative to the fixed coordinate system on the LINAC gantry.

30. The system of claim 28 further comprising a LINAC for targeting a beam of radiation to a tumor on the patient'"'"'s internal organ, wherein the LINAC includes a tray, and wherein the reference target is located at a known position relative to the fixed coordinate system on the LINAC tray.

31. The system of claim 30 wherein the LINAC tray is a blocking tray.

32. The system of claim 30 wherein the LINAC tray is a wedge tray.

33. The system of claim 17 wherein the system comprises a system for localizing a medical imaging device used in connection with a tissue biopsy procedure.

34. The system of claim 17 wherein the system comprises a system for localizing a medical imaging device used in connection with a spatially localized drug delivery procedure.

35. The system of claim 17 wherein the system comprises a system for localizing a medical imaging device used in connection with a spatially localized radiotherapy procedure.

36. The system of claim 17 wherein the system comprises a system for localizing a medical imaging device used in connection with an external beam radiation therapy treatment planning session.

37. The system of claim 17 wherein the system comprises a system for localizing a medical imaging device used in connection with an external beam radiation therapy treatment delivery session.

38. A localizable medical imaging probe comprising:

a medical imaging probe having a field of view; and

a tracking camera attached to the medical imaging probe in a known spatial relationship with respect to the probe'"'"'s field of view.

39. The probe of claim 38 wherein the tracking camera is attached to the probe such that the tracking camera images a reference target remote from the probe while the probe is being used to generate images of a patient, the reference target having a known position in a three-dimensional coordinate system.

40. The probe of claim 39 wherein the medical imaging probe is a freehand ultrasound probe.

41. The probe of claim 40 wherein the reference target is located at a fixed position in the coordinate system.

42. The probe of claim 40 wherein the tracking camera is a CCD imager.

43. The probe of claim 40 wherein the tracking camera is detachable from the probe.

44. A localizable medical tool comprising:

a medical tool for use in a medical procedure with a patient; and

a tracking camera attached to the medical tool in a known spatial relationship with respect to a point of interest associated with the medical tool.

45. The localizable medical tool of claim 44 wherein the tracking camera is attached to the medical tool such that the tracking camera images a reference target remote from the probe while the medical tool is being used in connection with a medical procedure, the reference target having a known position in a three-dimensional coordinate system.

46. The localizable medical tool of claim 45 wherein the tracking camera is a CCD imager.

47. The localizable medical tool of claim 45 wherein the medical tool is a medical imaging device.

48. The localizable medical tool of claim 45 wherein the medical tool is a surgical instrument.

49. The localizable medical tool of claim 45 wherein the medical tool is a bite block for use in treating head or neck lesions.

50. A computer readable medium for localizing a medical tool relative to a fixed coordinate system of a room, wherein the medical tool comprises a camera attached thereto at a known position relative to a point of interest on the medical tool, the camera being configured to image a reference target disposed in the room remotely from the medical tool, the reference target having a known position relative to the coordinate system, the computer readable medium comprising:

a plurality of executable instructions for processing camera images received from the camera together with known position data to determine the position of the medical tool relative to the coordinate system, wherein the camera images at least partially depict the reference target.

51. The computer readable medium of claim 50 wherein the medical tool is a medical imaging device.

52. The computer readable medium of claim 51 wherein the medical imaging device is a freehand ultrasound probe, wherein the reference target comprises a plurality of printed marks arranged in a grid pattern that are visible to the tracking camera, and wherein the coordinate system origin is the machine isocenter of a linear accelerator, and wherein the plurality of executable instructions further comprise a plurality of executable instructions for processing camera images received from the camera together with known position data to determine, in substantially real-time, the position of the medical tool relative to the coordinate system, wherein the camera images at least partially depict the reference target.

53. The computer readable medium of claim 52 wherein the plurality of executable instructions for processing camera images include executable instructions for applying an edge detection, sharpening and pattern recognition algorithm to the camera images.

54. A system for localizing a medical tool, the system comprising:

a medical tool for use in a medical procedure with a patient;

a localization system associated with the medical tool that locates the medical tool in a three-dimensional coordinate system, the localization system comprising a reference target having a fixed and known position in the coordinate system, the reference target being remote from the medical tool; and

a computer in communication with the localization system, the computer being programmed to (1) receive data from the localization system, and (2) determine the position of the medical tool in the coordinate system at least partially on the basis of data received from the localization system.

55. The system of claim 54 wherein the localization system further comprises a sensor attached to the medical tool at a known position with respect to a point of interest on the medical tool, the sensor being configured to sense the reference target and generate data indicative of the reference target'"'"'s position in the coordinate system, wherein the data received by the computer from the localization system comprises the sensor data from the sensor, and wherein the computer is programmed to determine the position of the medical tool in the coordinate system at least partially on the basis of the sensor data.

56. The system of claim 55 wherein the sensor is a camera having a field of view within which the reference target at least partially resides, wherein the sensor data comprises image data generated by the camera of at least a portion of the reference target, and wherein the computer is programmed to determine the position of the medical tool in the coordinate system at least partially on the basis of the image data from the camera.

57. The system of claim 56 wherein the reference target comprises a plurality of identifiable marks thereon disposed in a known spatial relationship with each other.

58. The system of claim 57 wherein the identifiable marks comprise a plurality of passive reflectors.

59. The system of claim 58 wherein the identifiable marks comprise a plurality of printed marks visible to the camera.

60. The system of claim 59 wherein the printed marks are arranged in a grid pattern.

61. The system of claim 57 wherein the computer is further programmed to determine, in substantially real-time, the position of the medical tool in the coordinate system at least partially on the basis of the image data from the camera.

62. The system of claim 57 wherein the image data of the reference target generated by the camera comprises image data of at least a portion of the reference target.

63. The system of claim 58 wherein the medical tool is a medical imaging device.

64. The system of claim 63 wherein the medical imaging device is a freehand ultrasound probe.

65. The system of claim 57 wherein the medical tool is a surgical instrument.

66. The system of claim 57 wherein the medical tool is a bite block for use in treating head or neck lesions.

67. A system for localizing a medical imaging probe, the system comprising:

a reference target having a known position in a fixed coordinate system;

a medical imaging probe for receiving data from which a medical image of a patient is generated, the probe being remote from the reference target;

a tracking camera attached to the probe for tracking the reference target and generating at least one image within which the reference target is depicted; and

a computer configured to (a) receive the camera image and (b) process the received camera image to determine the position of the device relative to the coordinate system in 3D coordinate space.