Magnetic tracker system and method for use for surgical navigation

Patent metadata

Field	Value
Publication number	US-2016015292-A1
Application number	US-201414332015-A
Country	US
Kind code	A1
Filing date	Jul 15, 2014
Priority date	Jul 15, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

A method and system for magnetically tracking a device of interest generating a plurality of pre-determined multi-frequency signals. The method and system transmits a plurality of magnetic fields from a transmitter circuit based on the corresponding pre-determined multi-frequency signals. The magnetic fields propagating through an area of examination encompassing the device of interest and a magnetic sensor coupled to the device of interest. The method and system generate a sensor signal at the magnetic sensor indicative of field strength of the magnetic fields transmitted by the transmitter circuit. Further, the method and system determine a position of the magnetic sensor relative to the transmitter circuit based on the multi-frequency signals and the sensor signal.

First claim

What is claimed is:

1 . A method for magnetically tracking a device of interest, the method comprises:
generating a plurality of pre-determined multi-frequency signals; transmitting a plurality of magnetic fields from a transmitter circuit based on the corresponding pre-determined multi-frequency signals, the magnetic fields propagating through an area of examination encompassing a device of interest and a magnetic sensor coupled to the device of interest; generating a sensor signal at the magnetic sensor indicative of field strength of the magnetic fields transmitted by the transmitter circuit; and determining a position of the magnetic sensor relative to the transmitter circuit based on the multi-frequency signals and the sensor signal.

2 . The method of claim 1 , further comprising identifying at least one of the magnetic fields from the transmitter circuit based on at least first and second frequencies of the multi-frequency signal; and
wherein the position of the magnetic sensor is determined from the magnetic field identified.

3 . The method of claim 1 , wherein the multi-frequency signal is at least one from a group comprising a chirp signal, a frequency modulated signal, pseudo-random bit sequence, frequency shift keying, multiple frequency shift keying, multi-tone multi frequency signaling or a Golay code.

4 . The method of claim 1 , wherein the sensor signal includes a secondary component induced by a secondary magnetic field created by passive sources within the area of examination, the method further comprising excluding the second component from calculations of the position based on the multi-frequency signals.

5 . The method of claim 4 , further comprising isolating at least one of the magnetic fields transmitted by the transmit circuit from the sensor signal based on at least first and second frequencies of the multi-frequency signal; and
wherein the position of the magnetic sensor is determined from the magnetic field isolated. 6 , The method of claim 1 , wherein the magnetic sensor is a magneto-resistive sensor.

7 . The method of claim 1 , wherein each pre-determined multi-frequency signal has a known phase that is employed in the analysis of the sensor signals.

8 . The method of claim 1 , further comprising receiving field strength measurements of the magnetic field from a second magnetic sensor.

9 . The method of claim 8 , wherein the position is determined using the known relative positions of the first and second magnetic sensors.

10 . The method of claim 1 , wherein the transmitter circuit is coupled to at least three electromagnetic coils.

11 . The method of claim 1 , further comprising registering the position of the magnetic sensor with at least one medical image to form a position registered medical image.

12 . A magnetic tracking system for tracking a device of interest comprising:
a transmitter circuit configured to generate a plurality of magnetic fields based on corresponding pre-determined multi-frequency signals; wherein the magnetic fields propagate through an area of examination; a magnetic sensor coupled to the device of interest, the magnetic sensor configured to generate a sensor signal indicative of field strength of the magnetic fields transmitted by the transmitter circuit when positioned within the area of examination; a controller configured to determine a position of the magnetic sensor relative to the transmitter circuit based on the pre-determined multi-frequency signals and the sensor signal.

13 . The magnetic tracking system of claim 12 , wherein the controller is further configured to identify at least one of the magnetic fields from the transmitter circuit based on at least first and second frequencies of the multi-frequency signal.

14 . The magnetic tracking system of claim 12 , wherein the multi-frequency signal is at least one from a group comprising of a chirp signal, a frequency modulated signal, pseudo-random bit sequence, frequency shift keying, multiple frequency shift keying, multi-tone multi frequency signaling, or a Golay code.

15 . The magnetic tracking system of claim 12 , wherein the sensor signal includes a secondary component induced by a secondary magnetic field created by passive sources within the area of examination, the controller is further configured to exclude the second component from calculations of the position based on the multi-frequency signals.

16 . The magnetic tracking system of claim 15 , wherein the controller is further configured to isolate at least one of the magnetic fields transmitted by the transmit circuit from the sensor signal based on at least first and second frequencies of the multi-frequency signal.

17 . The magnetic tracking system of claim 12 , wherein the magnetic sensor is a magneto-resistive sensor.

18 . The magnetic tracking system of claim 12 , wherein each of the plurality of pre-determined multi-frequency signals have a known phase that is employed in the analysis of the sensor signals.

19 . The magnetic tracking system of claim 12 , further comprising a second magnetic sensor, wherein the controller is further configured to determine the position of the magnetic sensor relative to the second magnetic sensor.

20 . The magnetic tracking system of claim 12 , wherein the transmitter circuit is coupled to at least three electromagnetic coils.

Assignees

• Gen Electric

Inventors

• Lorraine Peter William
• Heukensfeldt Jansen Floribertus P M

Classifications

• A61B2090/376

  using X-rays, e.g. fluoroscopy · CPC title

• A61B2034/2051

  Electromagnetic tracking systems · CPC title

• A61B34/20

  Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis · CPC title

• A61B2562/0223

  Magnetic field sensors · CPC title

• A61B5/062 Primary

  using magnetic field · CPC title