Reference pad for position sensing

• US 20060241397A1
• Filed: 02/22/2005
• Published: 10/26/2006
• Est. Priority Date: 02/22/2005
• Status: Abandoned Application

• Current Assignee: Biosense Webster Incorporated (Johnson & Johnson)
• Original Assignee: Biosense Webster Incorporated (Johnson & Johnson)
• Inventors: Govari, Assaf, Altmann, Andres Claudio, Ephrath, Yaron
• Application Number:
  US11/063,094
• Publication Number:
  US 20060241397A1
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2090/3958 emitting a signal
• 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 5/062 using magnetic field
• CPC Class Codes: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for

Abstract

A method for position tracking includes attaching a location pad to a body of a subject and introducing into the body of the subject a first position transducer. A procedure is performed on the body of the subject using a medical tool, to which a second position transducer is fixed. Magnetic fields are transmitted between the location pad and first and second position transducers. Responsively to the magnetic fields, first and second position signals are generated. The signals are indicative of coordinates of the first and second position transducers relative to the location pad. The first and second position signals are processed so as to determine a disposition of the tool relative to the first position transducer.

Claims

1. A tracking system, comprising:

a location pad, which is configured to be attached to a body of a subject and to generate a magnetic field within the body;

a first position transducer, which is adapted to be introduced into the body of the subject and responsively to the magnetic field, to generate and transmit a first position signal that is indicative of first coordinates of the first position transducer relative to the location pad;

a second position transducer, which is fixed to a medical tool adapted for performing a procedure on the body of the subject and is adapted, responsively to the magnetic field, to generate and transmit a second position signal that is indicative of second coordinates of the second position transducer relative to the location pad; and

a system controller, which is coupled to receive and process the first and second position signals so as to determine a disposition of the tool relative to the first position transducer.

2. The system according to claim 1, wherein the location pad is one of at least first and second location pads, which are configured to be attached to the body at respective locations and to generate respective magnetic fields with respective ranges, and

wherein the first and second position transducers are adapted respectively to generate the first and second position signals responsively to the magnetic field within whose range they are located.

3. The system according to claim 2, wherein the system controller is adapted to determine pad coordinates of the first location pad relative to the second location pad, and thereby to register the first and second coordinates in a common reference frame.

4. The method according to claim 3, wherein the first location pad is adapted to generate a third position signal responsively to the magnetic field of the second location pad, and wherein the system controller is coupled to receive and process the third position signal in order to determine the pad coordinates.

5. The system according to claim 4, and comprising a third location pad, wherein the second location pad is adapted to generate a fourth position signal responsively to a magnetic field of the third location pad, and wherein the system controller is coupled to receive and process the fourth position signal in order to register the first, second and third location pads in the common reference frame.

6. The system according to claim 2, wherein the first and second location pads are mounted on a single unit, which is configured to be fixed to the body of the subject.

7. The system according to claim 1, and comprising a third position transducer, which is fixed in a frame of reference external to the body of the subject and is adapted to generate a third position signal responsively to the magnetic field,

wherein the system controller is coupled to receive and process the third position signal so as to determine the first and second coordinates in the external frame of the reference.

8. The system according to claim 1, wherein the location pad is adapted to be affixed to a surface of the body of the subject.

9. The system according to claim 1, wherein the location pad comprises a plurality of concentric, orthogonal magnetic field generating coils.

10. The system according to claim 1, wherein at least one of the first and second position transducers comprises one or more transducer coils, which are adapted to sense the magnetic fields so as to generate at least one of the first and second position signals.

11. The system according to claim 1, and comprising a driving antenna, which is adapted to radiate a radio frequency (RF) electromagnetic field, and

wherein the location pad comprises a power coil, which is coupled to receive the RF electromagnetic field and thereby to provide power for generating the magnetic field.

12. The system according to claim 1, wherein the location pad comprises an internal power source to provide power for generating the magnetic field.

13. The system according to claim 1, wherein the first and second position transducers comprise wireless transmitters for communicating with the system controller.

14. The system according to claim 1, wherein the first position transducer is coupled to communicate with the system controller via a wired connection.

15. The system according to claim 14, and comprising a first wire coupling the first position transducer to the location pad, and a second wire coupling the location pad to the system controller.

16. A tracking system, comprising:

a first position transducer, which is adapted to be introduced into a body of a subject and to generate a first magnetic field;

a second position transducer, which is fixed to a medical tool adapted for performing a procedure on the body of the subject and is adapted to generate a second magnetic field;

a location pad, which is configured to be attached to the body of the subject, to receive the first and second magnetic fields, and to generate and transmit first and second position signals that are indicative of respective first and second coordinates of the first and second position transducers relative to the location pad; and

a system controller, which is coupled to receive and process the first and second position signals so as to determine a disposition of the tool relative to the first position transducer.

17. The system according to claim 16, wherein the location pad is one of at least first and second location pads, which are configured to be attached to the body at respective locations, and

wherein the first and second location pads are adapted to receive the first and second magnetic fields within respective ranges, so that the first and second position signals are generated by the location pad within whose range the first and second position transducers are located.

18. The system according to claim 17, wherein the system controller is adapted to determine pad coordinates of the first location pad relative to the second location pad, and thereby to register the first and second coordinates in a common reference frame.

19. The system according to claim 18, wherein the first location pad is adapted to generate a third magnetic field, and wherein the second location pad, responsively to the third magnetic field, generates a third position signal, and wherein the system controller is coupled to receive and process the third position signal in order to determine the pad coordinates.

20. The system according to claim 19, and comprising a third location pad, wherein the second location pad is adapted to generate a fourth magnetic field, and wherein the third location pad, responsively to the fourth magnetic field of the third location pad, generates a fourth position signal, and wherein the system controller is coupled to receive and process the fourth position signal in order to register the first, second and third location pads in the common reference frame.

21. The system according to claim 16, wherein the first and second location pads are mounted on a single unit, which is configured to be fixed to the body of the subject.

22. The system according to claim 16, and comprising a third position transducer, which is fixed in a frame of reference external to the body of the subject and is adapted to generate a third magnetic field,

wherein the location pad is adapted responsively to the third magnetic field to generate a third position signal, and

wherein the system controller is coupled to receive and process the third position signal so as to determine the first and second coordinates in the external frame of the reference.

23. The system according to claim 16, wherein the location pad is adapted to be affixed to a surface of the body of the subject.

24. The system according to claim 16, wherein the location pad comprises a plurality of concentric, orthogonal coils for receiving the magnetic fields.

25. The system according to claim 16, wherein at least one of the first and second position transducers comprises one or more transducer coils, which are adapted to generate at least one of the first and second magnetic fields.

26. The system according to claim 16, wherein the location pad is adapted to transmit the first and second position signals over a wireless connection to the system controller.

27. A method for position tracking, comprising:

attaching a location pad to a body of a subject;

introducing into the body of the subject a first position transducer;

performing a procedure on the body of the subject using a medical tool, to which a second position transducer is fixed;

transmitting magnetic fields between the location pad and first and second position transducers;

responsively to the magnetic fields, generating first and second position signals that are indicative of coordinates of the first and second position transducers relative to the location pad; and

processing the first and second position signals so as to determine a disposition of the tool relative to the first position transducer.

28. The method according to claim 27, wherein transmitting the magnetic fields comprises transmitting the magnetic fields from the location pad, and wherein generating the first and second position signals comprises generating the first and second position signals responsively to the magnetic fields received at the first and second position transducers.

29. The method according to claim 27, wherein transmitting the magnetic fields comprises transmitting the magnetic fields from the first and second position transducers, and wherein generating the first and second position signals comprises generating the first and second position signals responsively to the magnetic fields received at the location pad from the first and second position transducers.

30. The method according to claim 27, wherein attaching the location pad comprises attaching first and second location pads to the body, each of the first and second location pads having a respective range, and

wherein the first and second position signals are indicative of the coordinates of the first and second position transducers relative to one of the first and second location pads within whose range the first and second position transducers are located.

31. The method according to claim 30, and comprising determining pad coordinates of the first location pad relative to the second location pad, and thereby registering the first and second coordinates in a common reference frame.

32. The method according to claim 31, wherein determining the pad coordinates comprises generating a third position signal responsively to a magnetic field transmitted between the first and second location pads, and receiving and processing the third position signal in order to determine the pad coordinates.

33. The method according to claim 32, wherein attaching the location pad further comprises attaching a third location pad to the body, and further comprising generating a fourth position signal responsively to a further magnetic field transmitted between the second and third location pads, and receiving and processing the fourth position signal in order to register the first, second and third location pads in the common reference frames.

34. The method according to claim 27, wherein attaching the location pad comprises mounting the first and second location pads on a single unit, which is configured to be fixed to the body of the subject.

35. The method according to claim 27, and comprising fixing a third position transducer in a frame of reference external to the body of the subject, generating a third position signal responsively to a magnetic field transmitted between the third position transducer and the location pad, and processing the third position signal so as to determine the first and second coordinates in the external frame of the reference.

36. The method according to claim 35, wherein processing the third position signal comprises monitoring movement of a part of the body of the subject using the first and third position transducers.

37. The method according to claim 27, wherein attaching the location pad comprises fixing the location pad to a surface of the body of the subject.

38. The method according to claim 27, and comprising transmitting a radio frequency (RF) electromagnetic field to provide power for generating the magnetic fields.

39. The method according to claim 27, wherein processing the first and second position signals comprises receiving the first and second position signals over a wireless connection.