X-ray calibration dummy, a method for non-marker-based registration for use in navigation-guided operations employing said x-ray calibration dummy, and a medical system having such an x-ray calibration dummy

• US 20020041655A1
• Filed: 09/24/2001
• Published: 04/11/2002
• Est. Priority Date: 09/25/2000
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Mitschke, Matthias
• Granted Patent: US 6,585,412 B2
• Time in Patent Office: Days
• US Class Current: 378/207
• 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

An X-ray calibration dummy (RP) having markings (4) that may be acquired by a position-acquisition system (30). The invention also concerns a method for nonmarker-based registration for use in navigation-guided operations employing the X-ray calibration dummy (RP). A medical system for carrying out the method has a C-shaped X-ray machine (10), a position-acquisition system, 30, and the X-ray calibration dummy (RP).

Claims

1. An X-ray calibration dummy having markings (3) that will appear on X-ray images for use in determining projection geometries of an X-ray system that may be rotated about an axis (A) used for reconstructing a volumnar record and markings (4) differing from the markings (3) that will appear on X-ray images, that may be acquired by a position-acquisition system (30) for non-marker-based registration for use in navigation-guided operations on an object (P) the markings (4) that may be acquired by the position-acquisition system (30) being arranged within a first zone (1) of the X-ray calibration dummy (RP) and the markings (3) that will appear on X-ray images being arranged within a second zone (2) of said X-ray calibration dummy that differs from the first zone (1).

2. The X-ray calibration dummy as claimed in claim 1, which dummy has a cylindrical shape, the first zone (1) being one of the ends of the cylindrically shaped X-ray calibration dummy (RP) and the second zone (2) being the lateral surface of same.

3. The X-ray calibration dummy as claimed in claim 1 or 2, in which the markings (4) that may be acquired by the position-acquisition system (30) are arranged on at least one marker plate (5) attached to the X-ray calibration dummy (RP).

4. The X-ray calibration dummy as claimed in claims 1 through 3, in which the markings (3) that will appear on X-ray images are arranged in the form of a helix.

5. A method for non-marker-based registration for use in navigation-guided operations employing a position-acquisition system (30), an X-ray machine (10) and an X-ray calibration dummy (RP), the X-ray machine (10) and the X-ray calibration dummy (RP) being provided with markings (4, 33) that may be acquired by the position-acquisition system (30), having the following method steps:

a) orienting the X-ray machine (10) and the X-ray calibration dummy (RP) relative to one another such that a coordinate system (O_P) assigned to the X-ray calibration dummy (RP) at least largely coincides with coordinate system (O_W) of a volume to be reconstructed of a first object (P) to be X-rayed by the X-ray machine (10) in a subsequent measurement on the object (P) or such that the positions of both of the coordinate systems, (O_P and O_W) relative to one another are either known or may be determined in a simple manner,

b) determining the position and orientation of the coordinate system (O_P) of the X-ray calibration dummy (RP) or the coordinate system O_W of the volume to be reconstructed and of a coordinate system (O_R) assigned to the X-ray machine (10) and

c) determining the transformation relationship between the coordinate system (O_R) of the X-ray machine (10) and the coordinate system (O_P) of the X-ray calibration dummy (RP) or the coordinate system (O_W) of the volume to be reconstructed.

6. The method as claimed in claim 5, in which the position of a second object (40) to be navigated relative to the first object (P) is acquired by the position-acquisition system (30).

7. The method as claimed in claim 5 or 6, in which a positioning mechanism (18) for positioning the first object (P) that has markings (35) that may be acquired by the position-acquisition system (30), the position of the positioning mechanism (18) being acquired by the position-acquisition system, 30, and a transformation relationship between a coordinate system (O_L) assigned to the positioning mechanism (18) and the coordinate system (O_P) of the X-ray calibration dummy (RP) or the coordinate system (O_W) of the volume to be reconstructed is determined.

8. The method as claimed in any of claims 5 through 7, in which the first object (P) is provided with markings (36) that may be acquired by the position-acquisition system (30) the position of the first object (P) being acquired by the position-acquisition system (30) and a transformation relationship between a coordinate system (O_O) assigned to the first object (P) and the coordinate system (O_W) of the volume to be reconstructed is determined.

9. The method as claimed in any of claims 5 through 8, in which, in addition to the markings (4) that may be acquired by the position-acquisition system (30) the X-ray calibration dummy (RP) also has markings (3) that will appear on X-ray images, an offline determination of the projection geometries of the X-ray machine (10) employed for reconstructing a volumnar record of the first object (P) from recorded 2D-projections of the first object (P) also taking place.

10. The method as claimed in claim 9, in which the X-ray calibration dummy (RP) has a cylindrical shape, the markings (3) that will appear on X-ray images being arranged in the form of a helix extending around the lateral surface (2) and at least one of the ends (1) being provided with markings (4) that may be acquired by the position-acquisition system (30).

11. The method as claimed in any of claims 5 through 10, in which the markings, 4, that may be acquired by the position-acquisition system (30) are arranged on a marker plate (5, 33, 35) attached to the X-ray calibration dummy (RP), to the X-ray machine (10) and/or to the positioning mechanism (18) respectively.

12. The method as claimed in any of claims 5 through 11, in which the X-ray machine is an adjustable C-shaped X-ray machine (10).

13. The method as claimed in claim 12, in which the C-shaped arc (17) of the C-shaped X-ray machine (10) is isocentrically adjustable.

15. The medical system as claimed in claim 14 having a positioning mechanism (18) for positioning the object (P) which positioning mechanism is provided with markings (35) that may be acquired by the position-acquisition system (30) such that the position of the positioning mechanism (18) may be acquired by the position-acquisition system (30).

16. The medical system as claimed in claim 14 or 15, in which the markings that may be acquired by the position-acquisition system (30) are arranged on a marker plate (5, 33, 35) attached to the X-ray calibration dummy (RP), to the X-ray machine (10) and/or to the positioning mechanism (18) respectively.

18. The medical system as claimed in claim 17, in which the X-ray calibration dummy (RP) has a cylindrical shape, the markings (3) that will appear on X-ray images being arranged in the form of a helix extending around the lateral surface (2) and at least one of the ends (1) being provided with markings (4) that may be acquired by the position-acquisition system (30).

20. The medical system as claimed in claim 19, in which the C-shaped arc (17) of the X-ray machine (10) is isocentrically adjustable.

14. A medical system having a position-acquisition system (30) an X-ray machine (10) and an X-ray calibration dummy (RP) the X-ray machine (10) and the X-ray calibration dummy (RP) being provided with markings (4) that may be acquired by the position-acquisition system (30) and it being possible for the X-ray machine (10) and the X-ray calibration dummy (RP) to be oriented relative to one another in a calibration operation such that a transformation relationship between a coordinate system (O_P) inscribed on the X-ray calibration dummy (RP) or a coordinate system (O_W) of a volume to be reconstructed of an object (P) to be X-rayed by the X-ray machine (10) in a subsequent measurement on the object (P) and a coordinate system (O_R) assigned to the X-ray machine (10) may be determined with the aid of the position-acquisition system (30).

17. The medical system as claimed in any of claims 14 through 16, in which, in addition to the markings (4) that may be acquired by the position-acquisition system (30) the X-ray calibration dummy (RP) has markings (3) that will appear on X-ray images.

19. The medical system as claimed in any of claims 14 through 18, in which the X-ray machine is an adjustable C-shaped X-ray machine (10).