SYSTEM FOR LOCAL ERROR COMPENSATION IN ELECTROMAGNETIC TRACKING SYSTEMS

• US 20100168556A1
• Filed: 03/22/2007
• Published: 07/01/2010
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kruecker, Jochen, Shen, Eric
• Granted Patent: US 9,733,336 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2090/0818 Redundant systems, e.g. using two independent measuring systems and comparing the signals
• CPC Class Codes: A61B 2090/3975 active
• 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
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence

Abstract

A system for local metal distortion correction for using an accurate electromagnetic tracking system in a medical environment is disclosed containing an electromagnetic field generator monitoring a medical device having a suitable sensor coil wherein a correction function, derived from an error correction tool, is applied to the position and orientation readings of the sensor coil. The error correction tool consists of a number of electromagnetic sensors arranged in a fixed and known geometric configuration and is placed surrounding the site of the medical procedure. Sensor data is displayed on an imaging system. In addition, a distortion mapping can be done utilizing optical sensors for relative positioning readings along with an electromagnetic tracking system sensor.

Claims

1. A method for local error compensation of metal distortions in using an Electromagnetic Tracking System (EMTS) comprising:

generating an electromagnetic field from at least one electromagnetic field generator;

monitoring a medical device having at least one electromagnetic sensor coil moving through an anatomy;

monitoring position readings from an error correction tool able to monitor metal distortions wherein said error correction tool is situated within proximity of said medical device comprising at least three electromagnetic sensors arranged in a known and fixed configuration;

deriving a correction function from said position readings and electromagnetic sensors;

applying said corrective function to said medical device monitoring to compensate for said metal distortion.

2. A method according to claim 1 wherein said error correction tool has at least four electromagnetic sensors.

3. A method according to claim 1 wherein said error correcting tool includes at least one optical tracking sensor attached to said tool in a fixed known position relative to at least one said electromagnetic sensor.

4. A method according to claim 3 wherein said position monitoring of said electromagnetic sensors, optical tracking sensors, and medical device are displayed on an imaging space.

5. A method according to claim 1 wherein a current is induced in said sensor coil of said medical device wherein said current is a function of the position and orientation of said sensor coil relative to said electromagnetic field generator.

6. An EMTS for accurately tracking a medical device through an anatomy comprising:

an electromagnetic field generator generating an electromagnetic field;

at least one medical device having an electromagnetic sensor coil in communication with said electromagnetic field generating a position reading;

an error correction tool generating an error correction function applied to said position reading of said medical device wherein said error correction tool comprises;

at least three electromagnetic sensors arranged in a known configuration.

7. An EMTS according to claim 6 wherein at least one optical tracking sensor is attached to said error correction tool in a fixed and known position relative to at least one electromagnetic sensor.

8. An EMTS according to claim 7 wherein said optical tracking sensor and electromagnetic sensor are registered to an imaging source providing a position reference for said error correction tool.

9. An EMTS according to claim 7 wherein said error correction tool has at least four electromagnetic sensors.

10. An EMTS according to claim 7 wherein a current is induced in said sensor coil of said medical device, said current is a function of the position and orientation of said sensor coil relative to said electromagnetic field generator.

11. A method for local error compensation of metal distortions in tracking medical devices using an EMTS comprising:

generating an electromagnetic field from at least one electromagnetic field generator having at least a first optical sensor;

a first platform capable of sustaining medical procedures having at least a second optical sensor;

a positioning system comprising

at least one Electromagnetic Tracking System (EMTS) sensor;

performing a compensation mapping comprising the steps of;

moving said positioning system to different locations within a desired spatial volume;

generating a correction function from known positioning of said electromagnetic field generator and said first platform relative to said positioning system;

wherein said first optical sensor, said second optical sensor and said EMTS sensor are in communication.

12. A method according to claim 11 wherein at least one medical device having at least one electromagnetic sensor coil is employed to perform a medical procedure.

13. A method according to claim 12 wherein a current is induced in said sensor coil of said medical device, said current is a function of the position and orientation of said sensor coil relative to said electromagnetic field generator.

14. A method according to claim 13 wherein said correction function is applied to a monitoring of said positioning and orientation of said sensor coil to compensate for medical distortion.

15. A method according to claim 14 wherein said monitoring of said positioning and orientation of said sensor coil compensated for medical distortion is displayed on an imaging source providing a position reference.

16. A method according claim 11 wherein said first optical sensor is a six degree of freedom optical tracking sensor.

17. A method according claim 11 wherein said second optical sensor is a six degree of freedom optical tracking sensor.