COIL ARRANGEMENT FOR AN ELECTROMAGNETIC TRACKING SYSTEM

• US 20090096443A1
• Filed: 10/11/2007
• Published: 04/16/2009
• Est. Priority Date: 10/11/2007
• Status: Active Grant

• Current Assignee: Stryker European Operations Holdings, LLC (Stryker Corporation)
• Original Assignee: General Electric Company
• Inventors: Anderson, Peter Traneus
• Granted Patent: US 8,391,952 B2
• Time in Patent Office: Days
• US Class Current: 324/207.17
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: G01R 33/00 Arrangements or instruments for measuring magnetic variables

Abstract

An electromagnetic tracking system comprising at least one electromagnetic transmitter assembly or at least one electromagnetic receiver assembly with two coils attachable to a trackable object to be tracked. The two coils including a first large coil and a second small coil, with the second small coil positioned asymmetrically with respect to the first large coil. The electromagnetic tracking system enables a medical professional to continually track the position and orientation of the object during a medical procedure.

Claims

1. An electromagnetic tracking system comprising:

at least one transmitter assembly with at least one transmitter coil;

at least one receiver assembly with two receiver coils attachable to an object to be tracked, the two receiver coils spaced apart from each other and positioned asymmetrically with respect to each other, the at least one receiver assembly communicating with and receiving signals from the at least one transmitter assembly; and

electronics coupled to and communicating with the at least one transmitter assembly and the at least one receiver assembly for calculating the position and orientation of the object to be tracked.

2. The electromagnetic tracking system of claim 1, wherein the two receiver coils include a first large coil and a second small coil.

3. The electromagnetic tracking system of claim 2, wherein the first large coil is aligned with a distal end of a medical instrument and the second small coil is positioned asymmetrically with respect to the first large coil.

4. The electromagnetic tracking system of claim 1, wherein the at least one receiver assembly is attachable to a proximal end of a medical instrument to track the position and orientation of a distal end of the medical instrument.

5. The electromagnetic tracking system of claim 1, wherein the two receiver coils are angled at different angles with respect to each other.

6. The electromagnetic tracking system of claim 2, wherein the first large coil is centered on a longitudinal axis and angled at a first angle with respect to the longitudinal axis and the second small coil is centered on the longitudinal axis and angled at a second angle with respect to the longitudinal axis.

7. The electromagnetic tracking system of claim 6, wherein the second angle of the second small coil is neither perpendicular to nor parallel with the first angle of the first large coil.

8. The electromagnetic tracking system of claim 2, wherein the second small coil is positioned asymmetrically with respect to the first large coil.

9. The electromagnetic tracking system of claim 1, wherein the object to be tracked is a medical device, implant or instrument.

10. An electromagnetic tracking system comprising:

at least one transmitter assembly with two transmitter coils attachable to an object to be tracked, the two transmitter coils spaced apart from each other and positioned asymmetrically with respect to each other;

at least one receiver assembly with at least one receiver coil, the at least one receiver assembly communicating with and receiving signals from the at least one transmitter assembly; and

electronics coupled to and communicating with the at least one transmitter assembly and the at least one receiver assembly for calculating the position and orientation of the object to be tracked.

11. The electromagnetic tracking system of claim 10, wherein the two transmitter coils include a first large coil and a second small coil, and wherein the second small coil is positioned asymmetrically with respect to the first large coil.

12. The electromagnetic tracking system of claim 11, wherein the first large coil is aligned with a distal end of a medical instrument and the second small coil is positioned asymmetrically with respect to the first large coil.

13. The electromagnetic tracking system of claim 10, wherein the at least one receiver assembly is attachable to a proximal end of a medical instrument to track the position and orientation of a distal end of the medical instrument.

14. The electromagnetic tracking system of claim 10, wherein the object to be tracked is a medical device, implant or instrument.

15. A transmitter assembly for an electromagnetic tracking system comprising a first large coil spaced apart from a second small coil, and the second small coil positioned asymmetrically with respect to the first large coil.

16. The transmitter assembly of claim 15, wherein the first large coil and the second small coil is coupled to an object to be tracked.

17. The transmitter assembly of claim 16, wherein the object to be tracked is a medical device, implant or instrument.

18. A receiver assembly for an electromagnetic tracking system comprising a first large coil spaced apart from a second small coil, and the second small coil positioned asymmetrically with respect to the first large coil.

19. The receiver assembly of claim 18, wherein the first large coil and the second small coil is coupled to an object to be tracked.

20. The receiver assembly of claim 19, wherein the object to be tracked is a medical device, implant or instrument.

21. A method of maximizing the tracking accuracy of an electromagnetic tracking system comprising:

attaching a first large coil and a second small coil to an object to be tracked; and

determining the position and orientation of the object to be tracked.

22. The method of claim 21, wherein the second small coil is positioned asymmetrically with respect to the first large coil.

23. The method of claim 21, wherein the step of determining the position and orientation of the object to be tracked includes applying a drive current to at least one coil of a transmitter assembly, measuring the magnetic field generated by the at least one coil of the transmitter assembly and received by at least one coil of a receiver assembly, and using the magnetic field measurements to calculate the position and orientation of the object to be tracked

24. The method of claim 21, wherein the object to be tracked is a medical device, implant or instrument.