ERROR CORRECTION TECHNIQUES IN SURGICAL NAVIGATION

• US 20120108954A1
• Filed: 10/29/2010
• Published: 05/03/2012
• Est. Priority Date: 10/29/2010
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Schulhauser, Randal C., Mattes, Michael F., Kallmyer, Todd A., Ruben, David A., Gerrish, Paul, Senarith, Patrick P., Klype, Per
• Granted Patent: US 9,913,693 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 2017/00703 correcting for movement of heart, e.g. ECG-triggered
• CPC Class Codes: A61B 2034/2048 using an accelerometer or inertia sensor
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2090/0818 Redundant systems, e.g. using two independent measuring systems and comparing the signals
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis

Abstract

A medical system includes a sensor location module, a first module, and a second module. The sensor location module determines a location of a magnetic field sensor within a magnetic field. The first module determines an acceleration of the magnetic field sensor. The second module indicates a modified location of the magnetic field sensor in an image of a medical patient based on the acceleration and one or more previously determined locations.

Claims

1. A medical system comprising:

a sensor location module that determines a location of a magnetic field sensor within a magnetic field;

a first module that determines an acceleration of the magnetic field sensor; and

a second module that indicates a modified location of the magnetic field sensor in an image of a medical patient based on the acceleration and one or more previously determined locations.

2. The medical system of claim 1, further comprising a modification module, wherein the modification module stores the one or more of the previously determined locations and generates a modified location value based on the acceleration of the magnetic field sensor and the one or more of the stored locations, wherein the second module indicates the location in the image based on the modified location value.

3. The medical system of claim 2, wherein the modification module determines when the acceleration is less than or equal to a threshold acceleration, and wherein the modification module stores the one or more of the previously determined locations when the acceleration is less than or equal to the threshold acceleration.

4. The medical system of claim 3, wherein the modification module determines when the acceleration is greater than the threshold acceleration, and wherein the modification module sets the modified location value to a value within a range of the one or more determined locations that were stored while the acceleration was less than or equal to the threshold acceleration.

5. The medical system of claim 3, wherein the modification module determines when the acceleration is greater than the threshold acceleration, and wherein the modification module sets the modified location value equal to one of the one or more determined locations that were stored while the acceleration was less than or equal to the threshold acceleration.

6. The surgical navigation system of claim 2, wherein the modification module sets the modified location value equal to a most recent determined location of the magnetic field sensor in response to the acceleration increasing from a value less than a threshold acceleration to a value that is greater than the threshold acceleration.

7. The surgical navigation system of claim 4, wherein the modification module maintains the modified location value at the value within the range for a predetermined period of time after the modification module determines that the acceleration is greater than the threshold acceleration.

8. The surgical navigation system of claim 4, wherein the modification module maintains the modified location value at the value within the range until the modification module determines that the acceleration value has decreased to a value less than the threshold acceleration.

9. The surgical navigation system of claim 8, wherein the modification module sets the modified location value to a current location determined by the sensor location module when the acceleration decreases to the value less than the threshold acceleration.

10. The surgical navigation system of claim 2, wherein the modification module:

stores a plurality of acceleration values determined by the first module;

stores a plurality of location values determined by the sensor location module;

determines a frequency content of the plurality of acceleration values; and

generates the modified location value based on analysis of the frequency content.

11. The surgical navigation system of claim 10, wherein the modification module:

determines when the acceleration values include greater than a threshold amount of frequency content within a predetermined range of frequencies; and

filters the plurality of location values to attenuate the predetermined range of frequencies included within the plurality of location values when the acceleration values include greater than the threshold amount of frequency content within the predetermined range of frequencies.

12. A method comprising:

determining a location of a magnetic field sensor within a magnetic field;

determining an acceleration of the magnetic field sensor; and

indicating a modified location of the magnetic field sensor in an image of a medical patient based on the acceleration and one or more previously determined locations.

13. The method of claim 12, further comprising:

storing the one or more of the previously determined locations;

generating a modified location value based on the acceleration of the magnetic field sensor and the one or more of the stored locations; and

indicating the location in the image based on the modified location value.

14. The method of claim 13, further comprising:

determining when the acceleration is less than or equal to a threshold acceleration; and

storing the one or more of the previously determined locations when the acceleration is less than or equal to the threshold acceleration.

15. The method of claim 14, further comprising:

determining when the acceleration is greater than the threshold acceleration; and

setting the modified location value to a value within a range of the one or more determined locations that were stored while the acceleration was less than or equal to the threshold acceleration.

16. The method of claim 14, further comprising:

determining when the acceleration is greater than the threshold acceleration; and

setting the modified location value equal to one of the one or more determined locations that were stored while the acceleration was less than or equal to the threshold acceleration.

17. The method of claim 13, further comprising setting the modified location value equal to a most recent determined location of the magnetic field sensor in response to the acceleration increasing from a value less than a threshold acceleration to a value that is greater than the threshold acceleration.

18. The method of claim 15, further comprising maintaining the modified location value at the value within the range for a predetermined period of time after determining that the acceleration is greater than the threshold acceleration.

19. The method of claim 15, further comprising maintaining the modified location value at the value within the range until determining that the acceleration value has decreased to a value less than the threshold acceleration.

20. The method of claim 19, further comprising setting the modified location value to a currently determined location when the acceleration decreases to the value less than the threshold acceleration.

21. The method of claim 13, further comprising:

storing a plurality of acceleration values;

storing a plurality of location values;

determining a frequency content of the plurality of acceleration values; and

generating the modified location value based on analysis of the frequency content.

22. The method of claim 21, further comprising:

determining when the acceleration values include greater than a threshold amount of frequency content within a predetermined range of frequencies; and

filtering the plurality of location values to attenuate the predetermined range of frequencies included within the plurality of location values when the acceleration values include greater than the threshold amount of frequency content within the predetermined range of frequencies.

23. A medical system comprising:

a magnetic field sensor;

a motion sensor;

an instrument including the magnetic field sensor and the motion sensor; and

a module that;

determines a location of the magnetic field sensor within a magnetic field based on signals received from the magnetic field sensor;

determines an amount of motion of the magnetic field sensor based on signals received from the motion sensor; and

indicates a modified location of the magnetic field sensor in an image of a medical patient based on the amount of motion and one or more previously determined locations.

24. The medical system of claim 23, further comprising a reference sensor, wherein the module determines a location of the reference sensor within the magnetic field based on signals received from the reference sensor, and wherein the determined location of the magnetic field sensor is expressed relative to the location of the reference sensor.

25. The medical system of claim 23, wherein the instrument is a catheter, and wherein the magnetic field sensor and the motion sensor are arranged in proximity to one another.

26. The medical system of claim 25, wherein the magnetic field sensor and the motion sensor are included in the same package, and wherein the catheter includes the package.

27. The medical system of claim 23, wherein the magnetic field sensor is one of a normal magnetoresistance (NMR) sensor, an anisotropic magnetoresistance (AMR) sensor, a giant magnetoresistance (GMR) sensor, and a Hall-effect sensor.

28. The medical system of claim 23, further comprising:

an electromagnetic field emitter that emits the magnetic field;

an imaging device that acquires the image of the patient; and

a display that displays the icon and the image of the patient.

29. The medical system of claim 23, wherein the motion sensor includes at least one of an accelerometer and a gyroscopic sensor.