Surgical navigation

• US 8,200,314 B2
• Filed: 01/22/2007
• Issued: 06/12/2012
• Est. Priority Date: 08/14/1992
• Status: Expired due to Fees

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Bladen, John Stuart, Anderson, Alan Patrick
• Primary Examiner(s): Casler, Brian
• Assistant Examiner(s): Santos, Joseph M
• Application Number:
  US11/655,890
• Publication Number:
  US 20070167722A1
• Time in Patent Office: 1,968 Days
• Field of Search: 600/117, 600/424, 600/427, 324/207.17, 378/62, 128/899, 702/152, 702/153
• US Class Current: 600/427
• CPC Class Codes: A61B 2017/00207 with hand gesture control or hand gesture recognition
• CPC Class Codes: A61B 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/742 Joysticks
• 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 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/064 using markers A61B5/062 takes precedence
• CPC Class Codes: A61B 5/6806 Gloves
• CPC Class Codes: G01B 7/004 for measuring coordinates of points
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• CPC Class Codes: H01F 2005/027 wound on formers for receiving several coils with perpendicular winding axes, e.g. for antennae or inductive power transfer

Abstract

Methods and apparatus are provided for locating the position, preferably in three dimensions, of a sensor by generating magnetic fields which are detected at the sensor. The magnetic fields are generated from a plurality of locations and, in one embodiment of the invention, enable both the orientation and location of a single coil sensor to be determined. The present invention thus finds application in many areas where the use of prior art sensors comprising two or more mutually perpendicular coils is inappropriate.

Claims

1. A method of determining a location and an orientation of an instrument relative to an anatomy, comprising:

obtaining image data of the anatomy;

displaying the obtained image data on a display device;

moving the instrument relative to the anatomy;

associating a sensor with the instrument;

providing a plurality of field generators at known locations each including a plurality of field generating elements;

energizing each of the plurality of field generating elements;

a. measuring the respective field generated by each of the plurality of field generating elements with the sensor;

b. calculating an estimate of a distance from a first field generator of the plurality of field generators to the sensor, based at least in part on the measurements of the field generated by each of the plurality of the field generating elements of the first field generator and an estimate of the orientation of the sensor;

c. calculating an estimate of the location of the sensor utilizing the calculated estimate of the distance from the first field generator of the plurality of field generators to the sensor and the known location of the field generators;

d. calculating a new estimate of the orientation of the sensor employing the calculated estimate of the location of the sensor and the measurements of the field at the sensor;

e. iteratively repeating portions (b) to (d) with portion (b) employing the new estimate of sensor orientation from the preceding portion (c) to improve the estimates of location and orientation of the sensor;

determining a first location and a first orientation of the sensor based at least in part on portion e.); and

displaying an icon representing the instrument on the display device based upon the determined first location and the first orientation of the sensor; and

further comprising;

i.) energizing a first field generating element of at least one of the plurality of field generators to establish a field;

ii.) measuring a value of the field strength at the sensor which is dependent on the location of the sensor within the field and calculating a field strength B;

iii.) repeating i.) and ii.) for each of the plurality of field generating elements for each of the plurality of the field generators;

iv.) calculating, by utilizing all the values measured in ii.) and iii.), an estimate of the direction of the sensor from the field generator and a direction dependent weighting factor for each field generating element so that the calculated field strength B is equal to a field strength B that would exist at the sensor if the axis of the field were directed towards the sensor;

v.) iteratively altering the direction dependent weighting factors to maximize the calculated field strength B to determine to a desired level of accuracy the direction of the sensor from the field generator; and

vi.) employing the calculated field strength B to calculate the distance of the sensor from the field generator and hence, from the direction of the sensor in v.) and the location of the sensor relative to the field generator.

2. The method of claim 1, wherein each of the plurality of the field generating elements of the first field generator is energized in sequence so that only one generating element is energized at any given time.

3. The method of claim 1, wherein at least two of the plurality of the field generating elements of the field generators are simultaneously energized, wherein a first of the at least two generating elements is energized at a different frequency than a second of the at least two generating elements.

4. The method of claim 1, wherein calculating a new estimate of the orientation of the sensor of portion d.) includes:

measuring the field at the sensor, calculating the direction of the respective field at the sensor, and the calculated estimate of the location of the sensor.

5. The method of claim 1, wherein determining the first location and first orientation is performed substantially continuously during a procedure on the anatomy.

6. The method of claim 5, further comprising:

forming a continuous representation on the display device based upon the continuous determination of the determined first location and first orientation.

7. The method of claim 1, further comprising:

performing a medical procedure on the anatomy wherein the medical procedure is performed at least in part with the instrument.

8. The method of claim 1, further comprising:

performing at least one of a colonoscopy, a bronchoscopy, a gastroscopy, a nasal gastric procedure, an endotracheal procedure, a cardiovascular procedure, a biopsy, or combinations thereof.

9. The method of claim 1, further comprising:

positioning each of the plurality of field generators substantially coplanar with one another.

10. The method of claim 1, displaying an icon representing the instrument on the display device based upon the determined first location and the first orientation of the sensor includes displaying a three dimensional representation of a location and an orientation of the instrument.

11. The method of claim 10, further comprising:

displaying the icon representing the instrument as a three-dimensional display of the instrument on the display device based upon the determined first location and the first orientation of the sensor according to a selected perspective of a user.

12. The method of claim 1, wherein associating a sensor with an instrument includes fixing the sensor near a distal end of the instrument.

13. The method of claim 1, wherein associating the sensor with the instrument includes:

providing the instrument with a substantially hollow interior;

positioning a moveable sensor within the instrument;

moving the sensor relative to the hollow interior of the instrument; and

displaying an icon illustrating at least a portion of a path of the provided instrument wherein the icon is operable to be rotated to view the icon in different perspectives in a three-dimensional manner.

14. The method of claim 1, wherein obtaining image data includes obtaining x-ray image data of the anatomy.

15. The method of claim 1, further comprising:

providing a processor; and

executing instructions with the processor to determine the location and orientation of the portion of the instrument including performing portions a. through e.

16. The method of claim 1, wherein

portion b.) calculating an estimate of a distance from the first field generator of the plurality of field generators to the sensor includes, calculating an estimate of a distance from each of the plurality of field generators to the sensor.

17. The method of claim 1, further comprising:

providing an imaging device; and

wherein obtaining the image data includes obtaining the image data with the provided imaging device.

18. The method of claim 1, wherein providing the instrument includes providing at least one of a catheter, an endoscope, a colonoscope, a biopsy tube, or combinations thereof.

19. The method of claim 1, further comprising:

providing at least one of the sensor, the field generating element, or combinations thereof as a coil.

20. The method of claim 1, wherein associating a sensor with the instrument includes associating a plurality of sensors with the instrument.

21. The method of claim 1, further comprising:

providing at least one of a display device, an instrument, an input device, a positioning system, or combinations thereof.

22. A method of determining a location and an orientation of an instrument within an anatomy, comprising:

providing a first location member at a known location operable to comprise a first plurality of collocated elements;

providing a second location member operable to comprise a second plurality of collocated elements;

energizing at least one of the first location member, the second location member, or combinations thereof to create a field and sensing the field with the other of at least one of the first location member, the second location member, or combinations thereof

measuring the field sensed by at least one of the first location member, the second location member, or combinations thereof; and

executing instructions with a computer processor to determine the location and the orientation of at least one of the first location member, the second location member, or combinations thereof including;

a. calculating an estimate of a distance between the first location member and the second location member based at least in part on a measurement of the generated field and an estimate of an orientation of at least one of the first location member, the second location member, or combinations thereof;

b. calculating an estimate of the location of the second location member utilizing the calculated estimate of distance and the known location of the first location member;

c. calculating a new estimate of an orientation of the second location member employing the calculated estimated location of the second location member and the measurements of the field with at least one of the first location member, the second location member, or combinations thereof; and

d. iteratively repeating portions (a) to (c), wherein portion (a) employs the calculated new estimate of the second location member orientation from the preceding portion (c) to improve the calculated estimate of the location of the second location member and the calculated new estimate of an orientation of at least one of the first location member, the second location member, or combinations thereof;

and further comprising;

i.) energizing a first field generating element of at least one of a plurality of field generators of the first location member or the second location member to establish a field;

ii.) measuring a value of the field strength at the other of the first location member or the second location member which is dependent on the location of the other of the first location member or the second location member within the field and calculating a field strength B;

iii.) repeating i.) and ii.) for each of the plurality of field generating elements for each of the plurality of the field generators;

iv.) calculating, by utilizing all the values measured in ii.) and iii.), an estimate of the direction of the other of the first location member or the second location member from the field generator and a direction dependent weighting factor for each field generating element so that the calculated field strength B is equal to a field strength B that would exist at the sensor if the axis of the field were directed towards the sensor;

v.) iteratively altering the direction dependent weighting factors to maximize the calculated field strength B to determine to a desired level of accuracy the direction of the other of the first location member or the second location member from the field generator; and

vi.) employing the calculated field strength B to calculate the distance of the other of the first location member or the second location member from the field generator and hence, from the direction of the sensor in v.) and the location of the sensor relative to the field generator.

23. The method of claim 22, wherein the first location member emits a field operable to be sensed by the second location member;

wherein the first location member includes a plurality of first location members substantially positioned in a single plane.

24. The method of claim 23, further comprising:

associating the second location member with an instrument; and

determining a location and an orientation of the instrument relative to the anatomy during a procedure.

25. The method of claim 24, further comprising:

obtaining image data of the anatomy;

displaying the image data of the anatomy on a display device; and

displaying an icon representing the determined location and orientation of the instrument relative to the anatomy.

26. The method of claim 25, further comprising:

displaying a substantially continuous representation of the determined location and orientation of the instrument in three dimensions by;

withdrawing the second location member through the instrument;

determining the location of the second location member while withdrawing the second location member; and

displaying the icon in three dimensions and allowing the perspective of viewing of the continuous representation to be altered among a plurality of directions.

27. The method of claim 22, wherein providing the first location member includes providing a field sensor and providing the second location member includes providing a field generator;

and

wherein providing the first location member includes providing a plurality of first location members in a substantially single plane.

28. The method of claim 27, further comprising:

sensing a field with each of the plurality of the first location members produced by the second location member.

29. The method of claim 22, further comprising:

performing a procedure on the anatomy.

30. The method of claim 22, further comprising:

obtaining x-ray image data of the anatomy.

31. The method of claim 22, further comprising:

providing an instrument including at least one of a colonoscope, an endoscope, a catheter, a biopsy tube, or combinations thereof.