Method for determining a coordinate transformation for use in navigating an object

• US 6,533,455 B2
• Filed: 08/31/2001
• Issued: 03/18/2003
• Est. Priority Date: 08/31/2000
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Graumann, Rainer, Mitschke, Matthias
• Primary Examiner(s): Dunn, Drew A.
• Assistant Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US09/944,933
• Publication Number:
  US 20020044631A1
• Time in Patent Office: 564 Days
• Field of Search: 378/162, 378/205, 378/207, 600/130, 600/424, 600/417, 600/426, 600/427, 600/429
• US Class Current: 378/205
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2065 Tracking using image or pattern recognition
• CPC Class Codes: A61B 2090/364 Correlation of different images or relation of image positions in respect to the body
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• 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 6/4405 the apparatus being movable or portable, e.g. handheld or mounted on a trolley
• CPC Class Codes: A61B 6/4441 the rigid structure being a C-arm or U-arm
• CPC Class Codes: A61B 6/547 involving tracking of position of the device or parts of the device
• CPC Class Codes: A61B 6/583 using calibration phantoms

Abstract

In a method for determining a coordinate transformation between a coordinate system of a first object to be imaged by an X-ray apparatus and a coordinate system of a second object to be navigated relative to a first object, a transformation relationship is determined between a coordinate system of a position-acquisition system and the coordinate system of the first object by an offline calibration run, the position of the X-ray arm is determined while recording X-ray images of the first object, and the position of the second object is determined using the position-acquisition system.

Claims

1. A method for determining a coordinate transformation between a coordinate system of a first object and a coordinate system of a second object to be navigated relative to said first object, comprising the steps of:

providing a position acquisition system having a coordinate system associated therewith;

providing an X-ray apparatus for obtaining an X-ray image of said first object;

providing a marking on said X-ray apparatus detectable by said position acquisition system, said marking having a coordinate system associated therewith;

executing a calibration run prior to obtaining said X-ray image;

in said calibration run, determining a coordinate transformation L between the coordinate system of said marking and the coordinate system of said position acquisition system, and a coordinate transformation V between the coordinate system of said position acquisition system and the coordinate system of said first object;

determining a modified coordinate transformation L′

between said coordinate system of said marking and said coordinate system of said position acquisition system resulting from an altered position of said X-ray apparatus and said position acquisition system relative to each other while obtaining said X-ray image of said first object using said X-ray apparatus;

determining a coordinate transformation L″

between the coordinate system of the second object and the coordinate system of the position acquisition system; and

determining a coordinate transformation between said coordinate system of said second object and the coordinate system of said first object using said coordinate transformations V, L, L′ and

L″

.

2. A method as claimed in claim 1 comprising determining a coordinate transformation M from said coordinate transformations L and L′

according to the relationship M=L′

L<sup>−

1.</sup>

3. A method as claimed in claim 2 comprising determining said coordinate transformation between the coordinate system of said second object and the coordinate system of said first object by VML″

.

4. A method as claimed in claim 1 comprising employing a C-arm X-ray apparatus as said X-ray apparatus.

5. A method for determining a coordinate transformation between a coordinate system of a first object and a coordinate system of a second object to be navigated relative to said first object, comprising the steps of:

providing a position acquisition system having a coordinate system associated therewith;

providing an X-ray apparatus for obtaining an X-ray image of said first object;

providing a marking on said X-ray apparatus detectable by said position acquisition system, said marking having a coordinate system associated therewith;

executing a calibration run prior to obtaining said X-ray image, including placing said X-ray apparatus in a reference position relative to said first object;

in said calibration run, determining a coordinate transformation S between the coordinate system of said marking, when said X-ray apparatus is in said reference position, and the coordinate system of said first object;

determining a coordinate transformation L_S′

between the coordinate system of said marking at said reference position of said X-ray apparatus and the coordinate system of said position acquisition system while obtaining said X-ray image of said first object;

determining a coordinate transformation L″

between the coordinate system of the second object and the coordinate system of the position acquisition system; and

determining a coordinate transformation between said coordinate system of said second object and the coordinate system of said first object using said coordinate transformations L_S′

, L″ and

S.

6. A method as claimed in claim 5 comprising determining said coordinate transformation between the coordinate system of said second object and the coordinate system of said first object by SL_S′

<sup>−

1</sup>L″

.

7. A method as claimed in claim 5 comprising employing a C-arm X-ray apparatus as said X-ray apparatus.