Imaging probe and method of obtaining position and/or orientation information

• US 9,597,008 B2
• Filed: 09/06/2011
• Issued: 03/21/2017
• Est. Priority Date: 09/06/2011
• Status: Active Grant

• Current Assignee: eZono AG
• Original Assignee: eZono AG
• Inventors: Henkel, Rolf, Ventura Sobrino Patino, Eliseo, Von Offenberg Sweeney, Robert, Dunbar, Allan
• Primary Examiner(s): REMALY, MARK DONALD
• Application Number:
  US14/342,748
• Publication Number:
  US 20150080710A1
• Time in Patent Office: 2,023 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• 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 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 8/0833 involving detecting or locating foreign bodies or organic structures
• CPC Class Codes: A61B 8/14 Echo-tomography
• CPC Class Codes: A61B 8/4254 using sensors mounted on the probe
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence
• CPC Class Codes: G01R 33/0206 Three-component magnetometers
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: H01F 13/003 Methods and devices for magnetising permanent magnets permanent magnets H01F7/02
• CPC Class Codes: H01F 7/0273 Magnetic circuits with PM for magnetic field generation

Abstract

A method of obtaining information about the position and/or orientation of a magnetic component relatively to a magnetometric detector, the magnetic component and the magnetometric detector being moveable independently from each other relatively to a static secondary magnetic field, the method comprising the steps of: measuring in the presence of the combination of both the magnetic field of the magnetic component and the static secondary magnetic field essentially simultaneously the strength and/or orientation of a magnetic field at at least a first position and a second position spatially associated with the magnetometric detector, the second position being distanced from the first position; and combining the results of the measurements to computationally eliminate the effect of the secondary magnetic field and derive the information about the position and/or orientation of the magnetic component.

Claims

1. A method of obtaining information about at least one of a position and an orientation of a magnetized elongate component of a medical device relative to a magnetometric detector, the magnetized elongate component and the magnetometric detector being moveable independently from each other relative to a static secondary magnetic field, the method comprising:

obtaining measurements, in presence of a combination of the magnetic field of the magnetized elongate component and the static secondary magnetic field essentially simultaneously, of at least one of a strength and an orientation of a magnetic field at at least a first position and a second position spatially associated with the magnetometric detector, the second position being distanced from the first position; and

combining the measurements to computationally eliminate an effect of the static secondary magnetic field by fitting the measurements to a model of the magnetic field of the magnetized elongate component, said model modeling the magnetic field of the magnetized elongate component as two spaced-apart magnetic charges, to derive the information about at least one of the position and the orientation of the magnetized elongate component.

2. The method according to claim 1, further comprising:

using at least one of the strength and the orientation of the magnetic field as measured at at least one of the first and second positions as a direct estimate of the at least one of the strength and the orientation of the static secondary magnetic field.

18. The method according to claim 1, wherein the magnetometric detector is removably attachable to an imaging probe for imaging tissue of a patient.

20. The method according to claim 18, wherein the imaging probe includes an ultrasound imaging probe.

22. The method according to claim 1, herein further comprising:

obtaining a measurement of the magnetic field at a third position spatially associated with the magnetometric detector, the third position being distanced from the first position and the second position, and

combining the measurements at the first, second and third positions to computationally eliminate an effect of the static secondary magnetic field and derive the at least one of the position and the orientation of the magnetized elongate component.

23. The method according to claim 1, comprising obtaining from the measurements a change in the at least one of the orientation and the position of the magnetometric detector due to its movement.

24. The method according to claim 1, wherein the magnetized elongate component includes individual parts and the method further comprises tracking individually the individual parts of the magnetized elongate component with respect to at least one of their position and orientation.

25. The method according to claim 1, wherein said obtaining measurements further comprises measuring at the first position components of the magnetic field in at least two linearly independent spatial directions.

26. The method according to claim 1, further comprising transmitting the measurements to a base unit for processing, the base unit being separate from the magnetometric detector.

27. The method according to claim 26, further comprising the magnetometric detector receiving information from the base unit.

28. The method according to claim 1, wherein the magnetometric detector includes plural magnetometers and said obtaining measurements further comprises measuring the magnetic field at each of the positions by each magnetometer.

29. The method according to claim 28, further comprising calibrating the magnetometers of the magnetometric detector with regard to gain, offset, and orientation so that a homogeneous magnetic field yields essentially identical measurements in all magnetometers.

30. The method according to claim 28, further comprising calibrating the magnetometers of the magnetometric detector in an inhomogeneous magnetic field to obtain relative spatial locations of the magnetometers of the magnetometric detector.

31. The method according to claim 1, wherein the magnetometric detector is integral with an imaging probe for imaging tissue of a patient.

32. The method according to claim 31, wherein the imaging probe includes an ultrasound imaging probe.

33. The method according to claim 31, further comprising transmitting position-related information produced by the magnetometric detector and image information produced by the imaging probe from the magnetometric detector and the imaging probe, respectively, to a base unit and combining the information in the base unit to generate an image of the tissue of the patient in which a position of at least a part of a medical device is indicated based on the at least one of the position and the orientation information obtained.

34. The method according to claim 33, further comprising indicating in the image whether at least part of the medical device is located in a pre-determined spatial plane.

3. A method of obtaining information about at least one of a position and an orientation of a magnetized elongate component of a medical device relative to a magnetometric detector, the magnetized elongate component and the magnetometric detector being moveable independently of each other relative to a static secondary magnetic field, the method comprising:

obtaining measurements, in presence of both the magnetic field of the magnetized elongate component and the static secondary magnetic field essentially simultaneously, of at least one of a strength and an orientation of a magnetic field at at least a first position spatially associated with the magnetometric detector and at least one of an acceleration and/or orientation of the magnetometric detector by means of a inertial measurement unit comprised in the magnetometric detector; and

combining the measurements to computationally eliminate an effect of the static secondary magnetic field by fitting the measurements to a model of the magnetic field of the magnetized elongate component, said model modeling the magnetic field of the magnetized elongate component as two spaced-apart magnetic charges, to derive the information about the at least one of the position and the orientation of the magnetized elongate component.

4. The method according to claim 3, further comprising:

obtaining measurements of at least one of the strength and the orientation of the magnetic field at a second position spatially associated with the magnetometric detector, the second position being distanced from the first position, and

combining the measurements at the first and second positions to computationally eliminate an effect of the static secondary magnetic field and derive the information about the at least one of the position and the orientation of the magnetized elongate component.

5. The method according to claim 4, further comprising obtaining measurement of the magnetic field at a third position spatially associated with the magnetometric detector, the third position being distanced from the first position and the second position, and combining the measurements to computationally eliminate an effect of the static secondary magnetic field and derive the at least one of the position and the orientation of the magnetized elongate component.

6. The method according to claim 4, further comprising obtaining from the measurements a change in the at least one of the orientation and the position of the magnetometric detector due to its movement.

7. The method according to claim 4, wherein the magnetized elongate component includes individual parts and the method further comprises tracking individually the individual parts of the magnetized elongate component with respect to at least one of their position and orientation.

8. The method according to claim 4, wherein obtaining measurements of the magnetic field includes measuring components of the magnetic field in at least two linearly independent spatial directions at the first position.

9. The method according to claim 4, further comprising transmitting the measurements to a base unit for processing, the base unit being separate from the magnetometric detector.

10. The method according to claim 9, further comprising the magnetometric detector receiving information from the base unit.

11. The method according to claim 4, wherein the magnetometric detector includes plural magnetometers and said obtaining measurements further comprises measuring the magnetic field at each of the positions by each magnetometer.

12. The method according to claim 11, further comprising calibrating the magnetometers of the magnetometric detector regard to gain, offset and orientation so that a homogeneous magnetic field yields essentially identical measurements in all magnetometers.

13. The method according to claim 11, further comprising calibrating the magnetometers of the magnetometric detector in an inhomogeneous magnetic field to obtain relative spatial locations of the magnetometers of the magnetometric detector.

14. The method according to claim 4, wherein the magnetometric detector is integral with an imaging probe for imaging tissue of a patient.

15. The method according to claim 14, wherein the imaging probe includes an ultrasound imaging probe.

16. The method according to claim 14, further comprising transmitting position-related information produced by the magnetometric detector and image information produced by the imaging probe from the magnetometric detector and the imaging probe, respectively, to a base unit, and combining the information in the base unit to generate an image of the tissue of the patient in which a position of at least a part of a medical device is indicated based on the at least one of the position and the orientation information.

17. The method of claim 16, further comprising indicating in the image whether at least part of the medical device is located in a pre-determined spatial plane.

19. The method according to claim 4, wherein the magnetometric detector is removably attachable to an imaging probe for imaging tissue of a patient.

21. The method according to claim 19, wherein the imaging probe includes an ultrasound imaging probe.