Coil arrangement for electromagnetic tracker method and system

• US 20080174304A1
• Filed: 01/18/2007
• Published: 07/24/2008
• Est. Priority Date: 01/18/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Anderson, Peter Traneus
• Granted Patent: US 7,573,258 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 2090/397 electromagnetic other than visible, e.g. microwave
• 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 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01D 5/208 using polyphase currents

Abstract

An electromagnetic coil arrangement comprising a plurality of electromagnetic sensors located about the periphery of a region and at least one center electromagnetic sensor located at or near the center of the region, wherein the plurality of electromagnetic sensors and the at least one center electromagnetic sensor are located in a single plane. An electromagnetic tracking system and method of use, the electromagnetic tracking system comprising the electromagnetic coil arrangement, at least one complementary electromagnetic sensor, and a processor configured to process a signal comprising data indicative of a mutual inductance between the at least one complementary electromagnetic sensor and each of the electromagnetic sensors of the electromagnetic coil arrangement.

Claims

1. An electromagnetic coil arrangement, comprising:

a plurality of electromagnetic sensors located about the periphery of a region; and

at least one center electromagnetic sensor located at or near the center of the region;

wherein the plurality of electromagnetic sensors and the at least one center electromagnetic sensor are located in a single plane.

2. The electromagnetic coil arrangement of claim 1, wherein each of the electromagnetic sensors comprises a single dipole electromagnetic coil or an electromagnetic coil trio.

3. The electromagnetic coil arrangement of claim 1, wherein each of the electromagnetic sensors is configured to generate at least one magnetic field.

4. The electromagnetic coil arrangement of claim 1, wherein each of the electromagnetic sensors is configured to sense at least one magnetic field.

5. The electromagnetic coil arrangement of claim 1, comprising a plurality of the arrangements of electromagnetic sensors, wherein the plurality of the arrangements of electromagnetic sensors is located in a single plane, and wherein each of the plurality of arrangements is formed by sensors separate from the other arrangments.

6. The electromagnetic coil arrangement of claim 1, comprising a plurality of the arrangements of electromagnetic sensors, wherein the plurality of the arrangements of electromagnetic sensors is located in a single plane, and wherein each of the plurality of arrangments shares at least one sensor with another of the plurality of arrangements.

7. An electromagnetic coil arrangement, comprising:

a plurality of electromagnetic sensors located about the periphery of faces enclosing a volume; and

at least one center electromagnetic sensor located at or near the center of at least one of the faces.

8. The electromagnetic coil arrangement of claim 7, wherein the volume comprises six faces forming a substantially hexahedron configuration.

9. An electromagnetic tracking system, comprising:

an electromagnetic coil arrangement comprising a plurality of electromagnetic sensors located about the periphery of a region; and

at least one center electromagnetic sensor located at or near the center of the region, wherein the plurality of electromagnetic sensors and the at least one center electromagnetic sensor are located in a single plane;

at least one complementary electromagnetic sensor; and

a processor configured to process a signal comprising data indicative of a mutual inductance between the at least one complementary electromagnetic sensor and each of the electromagnetic sensors of the electromagnetic coil arrangement.

10. The electromagnetic tracking system of claim 9, wherein each of the electromagnetic sensors comprises a single dipole electromagnetic coil or an electromagnetic coil trio.

11. The electromagnetic tracking system of claim 9, wherein the at least one complementary electromagnetic sensor comprises a single dipole electromagnetic coil or an electromagnetic coil trio.

12. The electromagnetic tracking system of claim 9, wherein each of the electromagnetic sensors of the electromagnetic coil arrangement is configured to generate at least one magnetic field, and wherein the at least one complementary electromagnetic sensor is configured to sense at least one magnetic field.

13. The electromagnetic tracking system of claim 9, wherein each of the electromagnetic sensors of the electromagnetic coil arrangement is configured to sense at least one magnetic field, and wherein the at least one complementary electromagnetic sensor is configured to generate at least one magnetic field.

14. The electromagnetic tracking system of claim 9, wherein the processor is configured to determine position and/or orientation of the at least one complementary electromagnetic sensor.

15. The electromagnetic tracking system of claim 14, wherein the processor is configured to use triangulation to determine position and/or orientation, wherein triangulation comprises using ratios of mutual inductance sensed between each of the electromagnetic sensors of the electromagnetic coil arrangement and the at least one complementary electromagnetic sensor to determine position and/or orientation of the at least one complementary electromagnetic sensor.

16. The electromagnetic tracking system of claim 14, wherein the processor is configured to use the position and/or orientation as an estimate of position for use in subsequent processing.

17. The electromagnetic tracking system of claim 14, comprising a display configured to display the position and/or orientation of a medical instrument or a medical device.

18. The electromagnetic tracking system of claim 9, wherein the at least one complementary electromagnetic sensor is coupled to a medical device.

19. A method of electromagnetic tracking, comprising:

positioning at least one complementary electromagnetic sensor in a volume of interest with respect to an electromagnetic coil arrangement adjacent to the volume of interest, the coil arrangement comprising a plurality of electromagnetic sensors located about the periphery of a region; and

at least one center electromagnetic sensor located at or near the center of the region, wherein the plurality of electromagnetic sensors and the at least one center electromagnetic sensor are located in a single plane;

sensing a mutual inductance between at least one of the electromagnetic sensors of the electromagnetic coil arrangement and the at least one complementary electromagnetic sensor; and

processing a signal indicative of the mutual inductance.

20. The method of electromagnetic tracking of claim 19, wherein the at least one complementary electromagnetic sensor is coupled to a medical device.

21. The method of electromagnetic tracking of claim 19, wherein each of the electromagnetic sensors of the electromagnetic coil arrangement generate at least one magnetic field, and wherein sensing a mutual inductance comprises the at least one complementary electromagnetic sensor sensing at least one magnetic field.

22. The method of electromagnetic tracking of claim 19, wherein the at least one complementary electromagnetic sensor generates at least one magnetic field, and wherein sensing a mutual inductance comprises at least one of the electromagnetic sensors of the electromagnetic coil arrangement sensing a magnetic field.

23. The method of electromagnetic tracking of claim 19, wherein processing a signal indicative of mutual inductance of the magnetic field comprises determining a position and/or orientation of the at least one complementary electromagnetic sensor.

24. The method of electromagnetic tracking of claim 23, wherein determining the position and/or orientation comprises triangulation via ratios of mutual inductance sensed between the electromagnetic sensors of the electromagnetic coil arrangement and the at least one complementary electromagnetic sensor.

25. The method of electromagnetic tracking of claim 19, comprising displaying the position and/or orientation on a monitor.

26. The method of electromagnetic tracking of claim 19, wherein processing a signal indicative of the mutual inductance comprises solving for the distance between sensors, R, in the equation:

$L=\frac{{\mathrm{\mu <br><br>}}_o\times <br><br>A_{\mathrm{effc}}\times <br><br>A_{\mathrm{effe}}}{R^3}\times <br><br>C_1$

and wherein;

L=mutual inductance magnitude in henries

μ

_o=the permeability of free space=Π

*4×

10<sup>−

7</sup> henries/meter

R=distance between sensors

C₁=a factor between 1 and 2 that may be determined based upon the orientation of the generating sensor.