Registration of human anatomy integrated for electromagnetic localization

• US 8,548,565 B2
• Filed: 02/01/2010
• Issued: 10/01/2013
• Est. Priority Date: 10/28/1999
• Status: Expired due to Fees

• Current Assignee: Medtronic Navigation Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Navigation Incorporated (Medtronic Plc)
• Inventors: Hunter, Mark W., Kessman, Paul
• Primary Examiner(s): Cheng, Jacqueline
• Application Number:
  US12/697,841
• Publication Number:
  US 20100137707A1
• Time in Patent Office: 1,338 Days
• Field of Search: 600/424, 600/407
• 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 2090/363 Use of fiducial points
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61B 2090/3958 emitting a signal
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• 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 90/36 Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: G06T 3/14 Transformations for image registration, e.g. adjusting or mapping for alignment of images

Abstract

A method for use during a procedure on a body. The method generates a display representing relative positions of two structures during the procedure. The method comprises the steps of storing an image data set in memory, the image data set representing the position of the body based on scans taken of the body prior to the procedure; reading the image data set stored in the memory, the image data set having a plurality of data points in known relation to a plurality of reference points for at least one of the two structures; placing one or more magnetic field sensors in known relation to the reference points of the two structures; generating a magnetic field; detecting the magnetic field with the magnetic field sensors; ascertaining the locations of the sensors based upon the magnetic field detected by the sensors and processing the locations of the sensors to generate a displaced image data set representing the relative position of the two structures during the procedure; and generating a display based on the displaced image data set illustrating the relative position of the two structures during the procedure.

Claims

1. A system for displaying relative positions of two structures during a procedure on a body, the system comprising:

a memory for storing an image data set representing the position of the body based on scans of the body, the image data set having a plurality of data points in known relation to a plurality of reference points for the body;

a magnetic field generator for generating a magnetic field;

a plurality of magnetic field sensors placed in known relation to at least one of the plurality of reference points for the body, the plurality of magnetic field sensors operable to sense the magnetic field and to generate a position signal in response to the sensed magnetic field;

a processor configured to execute instructions to,

receive the position signal for ascertaining a location of at least a first sub-plurality of the plurality of magnetic field sensors based upon the position signal,

register the ascertained location of at least the first sub-plurality of the plurality of magnetic field sensors and the image data set based on the known relation of at least the first sub-plurality of the plurality of magnetic field sensors relative to the at least one of the plurality of reference points and the received position signal from at least the first sub-plurality of the plurality of magnetic field sensors,

generate a displaced image data set representing relative positions of the plurality of reference points for the body during the procedure based on the registered image data set; and

learn a geometry of relative locations of at least a second sub-plurality of the plurality of magnetic field sensors placed on the body at a first time to perform an accuracy geometry check at a second time to ensure accuracy after the registration, wherein the second sub-plurality of the plurality of magnetic field sensors placed on the body are configured to remain substantially fixed in the learned geometry between the first time and the second time; and

a display to display the displaced image data set generated by the processor to display the relative position of the plurality of reference points for the body during the procedure.

2. The system of claim 1, wherein the plurality of reference points are identifiable as points on body elements of the body to which the image data set relates.

3. The system of claim 1, further comprising:

a fiducial marker, wherein the fiducial marker defines the plurality of reference points for the body in the image data set;

wherein the fiducial marker is placed on the body prior to the image data set being acquired of the body;

wherein the processor is further configured to identify the fiducial marker in the image data set using image algorithms and wherein the fiducial marker is represented by at least the plurality of reference points in the image data set.

4. The system of claim 3, wherein the image data set is a three-dimensional data set that has data points corresponding to the plurality of reference points defined by the fiducial marker.

5. The system of claim 4,

wherein the first sub-plurality of the plurality of magnetic field sensors is placed on a first vertebra on the body and at least the second sub-plurality of the plurality of magnetic field sensors is placed on a second vertebra on the body;

wherein the processor is configured to dynamically track movement of each of the first sub-plurality of magnetic field sensors and the second sub-plurality of magnetic field sensors to track alignment and positioning of both the first vertebra and the second vertebra.

6. The system of claim 5, wherein the processor is configured to track relative movement of both the first vertebra and the second vertebra.

7. The system of claim 1, further comprising:

an instrument operable to be moved relative to the body; and

an instrument magnetic field sensor configured to sense the magnetic field and to generate an instrument position signal in response to the sensed magnetic field;

wherein the processor is configured to determine the relative location of the instrument relative to the body based on the instrument position signal and the position signal and generate for display with the display a representation of the instrument relative to the body.

8. A system for displaying relative positions of two structures during a procedure on a body, the system comprising:

a first fiducial marker that defines at least a first reference point and a second fiducial marker that defines at least a second reference point, both operable to be connected to the body during an acquisition of an image data set representing the body;

a memory for storing the image data set representing the body, the image data set having a plurality of body data points in known relation to the first reference point and the second reference point;

a magnetic field generator for generating a magnetic field;

a first magnetic field sensor placed in known relation to the first reference point on a first body portion of the body and a second magnetic field sensor placed in known relation to the second reference point on a second body portion of the body, the first magnetic field sensor operable to sense the magnetic field and to generate a first position signal in response to the sensed magnetic field and the second magnetic field sensor operable to sense the magnetic field and to generate a second position signal in response to the sensed magnetic field;

a processor Configured to,

receive the first position signal and the second position signal,

ascertain a location of both the first Magnetic field sensor and the second magnetic field sensor based upon the received first position signal and the second position signal,

register the first magnetic field sensor and the second magnetic field sensor and the image data set based on both the known relation of the first magnetic field sensor relative to the first reference point and the ascertained location of the first magnetic field sensor and the known relation of the second magnetic field sensor relative to the second reference point and the ascertained location of the second magnetic field sensor, and

generate a displaced image data set representing relative positions of the first reference point and the second reference point for the body during the procedure based on the registered image data set;

determine a fixed geometry between the first magnetic field sensor and the second magnetic field sensor, wherein the first magnetic field sensor is positioned at the fixed geometry relative to the second magnetic field sensor; and

increase accuracy of the registered image data set by performing an accuracy check based on the determined fixed geometry and tracking the determined fixed geometry during the procedure; and

a display to display the displaced image data set generated by the processor to display the relative position of the first reference point and the second reference point for the body during the procedure.

9. The system of claim 8, wherein the first fiducial marker and the first magnetic field sensor are integrated info a single unit.

10. The system of claim 9, wherein the first reference point defined by the first fiducial marker is positioned a distance away from a connection portion of the first fiducial marker relative to the body.

11. The system of claim 8, wherein the first fiducial marker and the first magnetic field sensor are configured to be connected;

wherein the image data set is configured to be acquired with the first fiducial marker connected to the first body portion and the first magnetic field sensor is configured to be connected after the acquisition of the image data set.

12. The system of claim 11, wherein the processor is configured to register the image data set automatically based on the known relation of the first magnetic sensor relative to the first fiducial marker.

13. The system of claim 11, wherein the first reference point defined by the first fiducial marker is positioned a distance away from a connection portion of the first fiducial marker relative to the body.

14. A method for displaying relative positions of two structures during a procedure on a body, the method comprising:

accessing an image data set representing the position of the body based on scans of the body, the image data set having a plurality of data points in known relation to a plurality of reference points for the body;

generating a magnetic field with a magnetic field generator;

generating a first position signal with a first magnetic field sensor placed in known relation to at least one of the plurality of reference points for the body on a first body portion, wherein the first position signal from the first magnetic field sensor is in response to the sensed magnetic field;

generating a second position signal with a second magnetic field sensor placed in known relation to at least one of the plurality of reference points for the body on a second body portion, wherein the second position signal from the second magnetic field sensor is in response to the sensed magnetic field;

receiving the first position signal and the second position signal with a processor to ascertain a location of both the first magnetic field sensor and the second magnetic field sensor based upon the received first position signal and the second position signal;

registering, with the processor configured to register, the first magnetic field sensor and the second magnetic field sensor and the image data set based on the known relation of the first magnetic field sensor relative to the at least one of the plurality of reference points for the body on a first body portion and the second magnetic field sensor relative to the at least one of the plurality of reference points on the second body portion and the ascertained location of both the first magnetic field sensor and the second magnetic field sensor based upon the received first position signal and the received second position signal;

generating a displaced image data set with the processor representing relative positions of the plurality of reference points for the body during the procedure based on the registered image data set;

displaying the displaced image data set generated by the processor to display the relative position of the plurality of reference points for the body during the procedure;

determining a fixed geometry between the first magnetic field sensor and the second magnetic field sensor, wherein the first magnetic field sensor is positioned at the fixed geometry relative to the second magnetic field sensor; and

performing an accuracy check with the determined fixed geometry and tracking the geometry during the procedure to increase accuracy of the registered image data set.

15. The method of claim 14, wherein the first magnetic field sensor is connected to a first vertebra and the second magnetic field sensor is attached to a second vertebra separate from the first vertebra.

16. The method of claim 15, further comprising:

sensing the magnetic field with an instrument magnetic field sensor affixed to an instrument;

generating an instrument position signal in response to the sensed magnetic field with the instrument magnetic field sensor;

determining the relative location of the instrument relative to the body with the processor based on the instrument position signal and the ascertained location of both the first magnetic field sensor and the second magnetic field sensor based upon the received first position signal and the second position signal and generate for display with the display a representation of the instrument relative to the body.

17. The method of claim 16, wherein the instrument magnetic field sensor includes a first coil and a second coil positioned near a tip portion of the instrument.

18. The method of claim 17, wherein the first coil is positioned substantially orthogonal to the second coil to ascertain six degree of freedom of movement information regarding the instrument.

19. The method of claim 18, further comprising:

identifying a fiducial marker in image data set using image algorithms and wherein the fiducial marker is represented by at least the plurality of reference points in the image data set.

20. The method of claim 19, wherein identifying the fiducial marker includes at least a first fiducial marker and a second fiducial marker;

wherein the first magnetic field sensor is positioned on the first vertebra relative to the first fiducial Marker and the second magnetic field sensor is positioned on the second vertebra relative to the second fiducial marker;

wherein registering is automatically registering the image data with the processor based upon the known relative location of both the first magnetic field sensor relative to the first fiducial marker and the second magnetic field sensor relative to the second fiducial marker.