Calbration of a sensor assembly for use in medical position/orientation tracking

• US 9,846,218 B2
• Filed: 12/31/2012
• Issued: 12/19/2017
• Est. Priority Date: 12/31/2012
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Huber, William Hullinger, Kashef, Bahman E., Nagarkar, Kaustubh Ravindra
• Primary Examiner(s): Ishizuka, Yoshihisa
• Application Number:
  US13/731,388
• Publication Number:
  US 20140188422A1
• Time in Patent Office: 1,814 Days
• Field of Search: 702104, 324202
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: G01R 35/00 Testing or calibrating of apparatus covered by the other groups of this subclass

Abstract

A position and orientation system and method is provided. A magnetoresistance sensor is provided having a sensor array configured to measure magnetic fields and a metallic coil positioned within the magnetoresistance sensor. In certain embodiments, the magnetic coil may be used to generate a known magnetic field that, when measured by the sensor array, may be used to determine or update a calibration constant for the system.

Claims

1. A position and orientation system as utilized in navigation of a surgical or interventional device through vasculature of a patient'"'"'s body, the system comprising:

a magneto resistance sensor comprising

a sensor array that measures magnetic fields; and

a metallic coil positioned within the magneto resistance sensor at a fixed distance from the sensor array;

a controller configured to at least read out data from the sensor array;

a processor having processing circuitry coupled to the controller, wherein the processing circuitry calculate and update a transformation constant of a set of transmitter coils that calibrates the sensor array during calibration and tracking of the surgical or interventional device;

wherein the sensor array detects an external magnetic field and uses the transformation constant to generate position and orientation of the surgical or interventional device during the calibration and tracking; and

wherein the transformation constant is updated to compensate for variations in a plurality of factors.

2. The position and orientation system of claim 1, wherein the position and orientation is used to navigate the surgical or interventional device through vasculature of a patient'"'"'s body.

3. The position and orientation system of claim 1, wherein the sensor array is a one-axis sensor array, a two-axis sensor array, or a three-axis sensor array.

4. The position and orientation system of claim 1, wherein the magnetoresistance sensor is configured to measure the magnetic field by generating a voltage in response to magnetic fields.

5. The position and orientation system of claim 1, wherein the metallic coil is a calibration coil.

6. The position and orientation system of claim 1, wherein the metallic coil has a B/I value that does not change due to environmental changes, wherein the B/I value is a relationship between magnetic field B and current I.

7. The position and orientation system of claim 1, wherein the processing circuitry further processes the data read out from the sensor array in response to a calibration magnetic field to calculate the transformation constant.

8. The position and orientation system of claim 7, wherein the transformation constant is normalized against a calibration constant with a calibration algorithm.

9. A method, comprising:

driving a transmitter coil to generate a navigational electromagnetic field;

measuring a calibration electromagnetic field generated by a calibration coil at a calibration frequency not in use by the transmitter coil by detecting the calibration electromagnetic field with a sensor array on an electromagnetic sensor;

calculating and updating a transformation constant of the transmitter coil using processing circuitry to create an updated transformation constant as based on the measured calibration electromagnetic field during calibration and tracking of a surgical or interventional device;

calibrating the electromagnetic sensor at one or more transmitter frequencies based on the updated transformation constant;

measuring the navigational electromagnetic field using the calibrated sensor array on the calibrated electromagnetic sensor;

generating position and orientation data of the surgical or interventional device based on the measured navigational electromagnetic field and the updated transformation constant;

wherein the electromagnetic sensor is continuously calibrated during navigation; and

wherein the transformation constant is updated to compensate for variations in a plurality of factors.

10. The method of claim 9, wherein the position and orientation data is used to navigate the surgical or interventional device.

11. The method of claim 9, wherein the sensor array is a one-axis sensor array, a two-axis sensor array, or a three-axis sensor array.

12. The method of claim 9, wherein the magetoresistance sensor is configured to measure the magnetic field by generating a voltage in response to the navigational electromagnetic field and the calibration electromagnetic field.

13. The method of claim 9, wherein the calibration coil has a B/I value that does not change due to environmental changes, wherein the B/I value is a relationship between magnetic field B and current I.

14. The method of claim 9, wherein the processing circuitry further calculates the transformation constant, wherein the transformation constant is normalized against a calibration constant with a calibration algorithm.

15. The method of claim 9, wherein the calibration frequency is different than the one or more transmitter frequencies.

16. One or more tangible, non-transitory, machine-readable media collectively storing instructions executable by a processor to:

drive a transmitter coil to generate a navigational electromagnetic field;

measure a calibration electromagnetic field generated by a calibration coil at a calibration frequency not in use by the transmitter coil by detecting the calibration electromagnetic field with a sensor array on an electromagnetic sensor;

calculate and update a transformation constant of the transmitter coil based on the measured calibration electromagnetic field using processing circuitry to produce an updated transformation constant;

calibrate the electromagnetic sensor at one or more transmitter frequencies based on a calibration constant;

measure the navigational electromagnetic field using the calibrated sensor array on the calibrated electromagnetic sensor;

generate position and orientation data of a surgical or interventional device based on the measured navigational electromagnetic field and the updated transformation constant;

wherein the position and orientation of the surgical or interventional device changes during navigation and the transformation constant is continuously updated so that the electromagnetic sensor can be continuously calibrated; and

wherein the transformation constant is updated to compensate for variations in a plurality of factors.

17. The one or more tangible, non-transitory, machine-readable media of claim 16, wherein the position and orientation data is used to navigate the surgical or interventional device.

18. The one or more tangible, non-transitory, machine-readable media of claim 16, wherein the calibration coil has a B/I value that that does not change due to environmental changes, wherein the B/I value is a relationship between magnetic field B and current I.

19. The one or more tangible, non-transitory, machine-readable media of claim 16, wherein the sensor array is a one-axis sensor array, a two-axis sensor array, or a three-axis sensor array.