LOW-PROFILE LOCATION PAD

• US 20070265526A1
• Filed: 05/11/2006
• Published: 11/15/2007
• Est. Priority Date: 05/11/2006
• Status: Abandoned Application

• Current Assignee: Biosense Webster Incorporated (Johnson & Johnson)
• Original Assignee: Biosense Webster Incorporated (Johnson & Johnson)
• Inventors: Govari, Assaf, Ephrath, Yaron, Altmann, Andres
• Application Number:
  US11/382,830
• Publication Number:
  US 20070265526A1
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• 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 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/065 Determining position of the probe employing exclusively positioning means located on or in the probe, e.g. using position sensors arranged on the probe

Abstract

A magnetic position tracking system for performing a medical procedure on a patient who is positioned on an upper surface of a table includes a location pad, which is positioned on the upper surface of the table beneath the patient. The location pad includes one or more field generators, which are operative to generate respective magnetic fields and are arranged so that a thickness dimension of the location pad is no greater than 3 centimeters. A position sensor is fixed to an invasive medical device for insertion into a body of the patient, and is arranged to sense the magnetic fields so as to measure a position of the medical device in the body.

Claims

1. A magnetic position tracking system for use in performing a medical procedure on a patient who is positioned on an upper surface of a table, the system comprising:

a location pad, which is positioned on the upper surface of the table beneath the patient, and which comprises one or more field generators, which are operative to generate respective magnetic fields and are arranged so that a thickness dimension of the location pad is no greater than 3 centimeters; and

a position sensor, which is fixed to an invasive medical device for insertion into a body of the patient, and which is arranged to sense the magnetic fields so as to measure a position of the medical device in the body.

2. The system according to claim 1, wherein the one or more field generators comprise two or more field generators positioned in a common plane and oriented so that the respective magnetic fields are perpendicular to the plane, and comprising an auxiliary field generator oriented so as to generate an auxiliary magnetic field having a component parallel to the plane at locations within the common plane.

3. The system according to claim 2, wherein the location pad contains the auxiliary field generator without exceeding the thickness dimension.

4. The system according to claim 2, wherein the two or more field generators comprise field generating coils wound in parallel to the common plane, and wherein the auxiliary field generator comprises a field generating coil wound not in parallel to the common plane.

5. The system according to claim 2, and comprising a reference position sensor, which is attached to the body of the patient at a reference location adjacent to the common plane and is arranged to sense the auxiliary magnetic field and the magnetic fields generated by the two or more field generators so as to measure a position of the reference location.

6. The system according to claim 5, wherein the reference position sensor is arranged to accurately measure a vertical displacement of the reference location based on the sensed auxiliary magnetic field.

7. The system according to claim 5, and comprising a processor, which is arranged to calculate a position of the invasive medical device with respect to the body irrespective of patient movements based on magnetic field measurements provided by the position sensor fixed to the invasive medical device and by the reference position sensor.

8. The system according to claim 1, wherein the one or more field generators comprise two or more field generators positioned at known angles with respect to one another.

9. A magnetic position tracking system for use in performing a medical procedure on a patient who is positioned on an upper surface of a table, the system comprising:

a field generator, which is fixed to an invasive medical device for insertion into a body of the patient, and which is arranged to generate a magnetic field; and

a location pad, which is positioned on the upper surface of the table beneath the patient, and which comprises one or more position sensors, which are operative to sense the magnetic field so as to measure a position of the medical device in the body, and are arranged so that a thickness dimension of the location pad is no greater than 3 centimeters.

10. The system according to claim 9, wherein the one or more position sensors comprise two or more position sensors positioned in a common plane and oriented so as to sense components of the magnetic field perpendicular to the plane, and comprising an auxiliary position sensor oriented so as to sense a magnetic field component parallel to the plane.

11. A location pad for use in a magnetic position tracking system, comprising:

one or more primary field generators, which are arranged in a common plane and are oriented so as to generate respective primary magnetic fields perpendicular to the plane; and

an auxiliary field generator oriented to generate an auxiliary magnetic field having a component at locations within the plane that is parallel to the plane,

wherein the primary and auxiliary field generators are arranged so that a thickness dimension of the location pad is no greater than 3 centimeters.

12. A method for performing a medical procedure on a patient who is positioned on an upper surface of a table, the method comprising:

positioning on the upper surface of the table beneath the patient a location pad comprising one or more field generators operative to generate respective magnetic fields and arranged so that a thickness dimension of the location pad is no greater than 3 centimeters; and

sensing the magnetic fields by a position sensor fixed to an invasive medical device inserted into a body of the patient, so as to measure a position of the medical device in the body.

13. The method according to claim 12, wherein the one or more field generators comprise two or more field generators, and wherein positioning the location pad comprises positioning the two or more field generators in a common plane and orienting the two or more field generators so that the respective magnetic fields are perpendicular to the plane, and comprising positioning and orienting an auxiliary field generator so as to generate an auxiliary magnetic field having a component parallel to the plane at locations within the common plane.

14. The method according to claim 13, wherein positioning the location pad comprises installing the auxiliary field generator in the location pad without exceeding the thickness dimension.

15. The method according to claim 13, wherein the two or more field generators and the auxiliary field generator comprise field generating coils having windings, and wherein positioning the location pad comprises orienting the windings of the two or more field generators in parallel to the common plane and orienting the windings of the auxiliary field generator in an angle not in parallel to the common plane.

16. The method according to claim 13, and comprising attaching a reference position sensor to the body of the patient at a reference location adjacent to the common plane, and sensing the auxiliary magnetic field and the magnetic fields generated by the two or more field generators by the reference position sensor so as to measure a position of the reference location.

17. The method according to claim 16, wherein sensing the auxiliary magnetic field comprises accurately measuring a vertical displacement of the reference location based on the sensed auxiliary magnetic field.

18. The method according to claim 16, and comprising calculating a position of the invasive medical device with respect to the body irrespective of patient movements based on magnetic field measurements provided by the position sensor fixed to the invasive medical device and by the reference position sensor.

19. The method according to claim 12, wherein the one or more field generators comprise two or more field generators positioned at known angles with respect to one another.

21. The method according to claim 19, wherein the one or more position sensors comprise two or more position sensors, and wherein positioning the location pad comprises positioning the two or more position sensors in a common plane and orienting the two or more position sensors so as to sense components of the magnetic field perpendicular to the plane, and positioning and orienting an auxiliary position sensor so as to sense a component of the magnetic field parallel to the plane.

20. A method for performing a medical procedure on a patient who is positioned on an upper surface of a table, the method comprising:

generating a magnetic field by a field generator fixed to an invasive medical device inserted into a body of the patient; and

positioning on the upper surface of the table beneath the patient a location pad comprising one or more position sensors, which are operative to sense the magnetic field so as to measure a position of the medical device in the body and are arranged so that a thickness dimension of the location pad is no greater than 3 centimeters.

22. A method for position tracking, comprising:

positioning and orienting one or more primary field generators in a common plane so as to generate respective primary magnetic fields perpendicular to the plane; and

positioning and orienting an auxiliary field generator to generate an auxiliary magnetic field having a component at locations within the plane that is parallel to the plane,

wherein the primary and auxiliary field generators are arranged so that a thickness dimension of the location pad is no greater than 3 centimeters.