Electromagnetic tracking system and method using a single-coil transmitter

• US 20050003757A1
• Filed: 07/01/2003
• Published: 01/06/2005
• Est. Priority Date: 07/01/2003
• Status: Active Grant

• Current Assignee: Northern Digital Inc. (Roper Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Anderson, Peter Traneus
• Granted Patent: US 7,158,754 B2
• Time in Patent Office: Days
• US Class Current: 455/41.100
• CPC Class Codes: A61B 2562/17 Comprising radiolucent components
• 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 5/062 using magnetic field

Abstract

Certain embodiments of the present invention provide a system and method for electromagnetic tracking using a single-coil transmitter. The system includes a single coil transmitter emitting a signal, a receiver receiving a signal from the single coil transmitter, and electronics for processing the signal received by the receiver. The electronics determine a position of the single coil transmitter. The transmitter may be a wireless or wired transmitter. The receiver may be a printed circuit board. In an embodiment, the receiver may be a twelve receiver circuit printed circuit board including single coils and/or pairs of coils. The electronics may determine position, orientation, and/or gain of the transmitter.

Claims

1. An electromagnetic tracking system, said system comprising:

a single coil transmitter emitting a signal;

a receiver receiving a signal from said single coil transmitter; and

electronics for processing said signal received by said receiver, said electronics determining a position of said single coil transmitter.

2. The system of claim 1, wherein said single coil transmitter comprises a wireless single coil transmitter.

3. The system of claim 1, wherein said single coil transmitter comprises a wired single coil transmitter.

4. The system of claim 1, wherein said single coil transmitter comprises a battery-powered single coil transmitter.

5. The system of claim 1, wherein said single coil transmitter is driven with a continuous wave signal.

6. The system of claim 1, wherein said single coil transmitter is a dipole single coil transmitter.

7. The system of claim 1, wherein said receiver comprises a printed circuit board.

8. The system of claim 1, wherein said receiver comprises a twelve-receiver array.

9. The system of claim 1, wherein said receiver comprises a twelve receiver circuit printed circuit board.

10. The system of claim 9, wherein four circuits include single spiral coils and eight circuits include pairs of spiral coils.

11. The system of claim 1, wherein said electronics further determines at least one of position, orientation, and gain of said transmitter.

12. The system of claim 1, wherein said electronics determines a ratio of mutual inductance between said transmitter and said receiver to determine said position of said transmitter.

13. The system of claim 1, wherein said electronics determines a ratio of currents produced at said transmitter to determine said position of said transmitter.

14. The system of claim 1, wherein said electronics determines a ratio of magnetic fields produced at said transmitter to determine said position of said transmitter.

15. An improved instrument tracking system, said system comprising:

a single-coil wireless transmitter;

a printed circuit board receiver array including a plurality of coils and coil pairs;

tracker electronics for analyzing at least one parameter between said transmitter and said coils and coil pairs of said receiver array to determine a position of said transmitter in relation to said receiver array.

16. The system of claim 15, wherein said parameters include at least one of mutual inductance and magnetic fields.

17. The system of claim 15, wherein said tracker electronics determines at least one of a gain and an orientation of said transmitter.

18. The system of claim 15, wherein reciprocity allows said coils of said receiver array to be treated as transmitter coils.

19. The system of claim 15, wherein said printed circuit board receiver array produces magnetic fields comprising:

a mostly uniform field point in an X direction;

a field varying mostly with X, pointed in the X direction;

a field varying mostly with Y, pointed in the X direction;

a field varying mostly with Z, pointed in the X direction;

a mostly uniform field pointed in the Y direction;

a field varying mostly with X, pointed in the Y direction;

a field varying mostly with Y, pointed in the Y direction;

a field varying mostly with Z pointed in the Y direction;

a mostly uniform field pointed in the Z direction;

a field varying mostly with X pointed in the Z direction;

a field varying mostly with Y pointed in the Z direction; and

a field varying mostly with Z pointed in the Z direction.

20. The system of claim 15, further comprising a calibration coil for calibrating said receiver array.

21. A method for improved instrument tracking, said method comprising:

driving a transmitter coil at a certain frequency to emit a signal;

receiving the signal at an array of receiver coils;

determining a gain of the transmitter coil;

measuring a mutual inductance between the transmitter coil and an array of receiver coils;

selecting an initial estimate of a position of the transmitter coil;

adjusting the initial estimate using an error-minimizing routine based on the mutual inductance.

22. The method of claim 21, wherein the initial estimate comprises a previous result.

23. The method of claim 21, further comprising calibrating the array of receiver coils.

24. The method of claim 21, further comprising eliminating a sign ambiguity of the gain of the transmitter coil.

25. The method of claim 21, further comprising determining a transmitter current from the signal received at the array of receiver coils.

26. A method for electromagnetic tracking, said method comprising:

driving an array of coils at different frequencies;

determining ratios of currents produced by the different frequencies;

measuring voltages generated at the different frequencies;

calculating ratios of mutual inductances between the array of coils and a single coil located remotely from said array of coils;

estimating an initial value for at least one of position, gain, and orientation of the single coil; and

determining a best fit value for at least one of the position, gain, and orientation of the single coil based on the initial value and the ratios of mutual inductances.

27. The method of claim 26, further comprising calibrating the array of coils.