X-ray apparatus for producing a 3D image from a set of 2D projections

• US 6,379,041 B1
• Filed: 03/21/2000
• Issued: 04/30/2002
• Est. Priority Date: 11/02/1998
• Status: Expired due to Term

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Mitschke, Matthias, Schuetz, Oliver
• Primary Examiner(s): DUNN, DREW A
• Application Number:
  US09/532,073
• Time in Patent Office: 770 Days
• Field of Search: 378/4, 378/62, 378/63, 378/196, 378/197, 378/198, 378/205, 378/901
• US Class Current: 378/205
• 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 apparatus has an X-ray examination system with an X-ray source and an X-ray detector which can be displaced relative to a subject for the pickup of 2D projections, an arrangement for determining extrinsic imaging parameters and an arrangement for determining intrinsic imaging parameters, for determining the projection geometry in the examination system for each 2D projection, and having a control and computing stage for reconstructing 3D images from the 2D projections using the extrinsic and intrinsic imaging parameters. The arrangement for determining the intrinsic imaging parameters includes X-ray-positive marks which are allocated to the X-ray source and which are in the path of an X-ray beam emanating from the X-ray source, these marks following displacement of the X-ray system.

Claims

1. An X-ray apparatus comprising:

an X-ray examination system having an X-ray source which emits an X-ray beam from a focus and an X-ray detector on which said X-ray beam is incident;

means for displacing said X-ray examination system relative to an examination subject while irradiating said examination subject with said X-ray beam from a plurality of different projection angles for obtaining a plurality of 2D projection images of said examination subject respectively at said plurality of different projection angles, each of said 2D projection images having a unique projection geometry associated therewith;

means for determining extrinsic imaging parameters and means for determining intrinsic imaging parameters for each of said 2D projection images, for determining the respective projection geometries for said 2D projection images, said means for determining intrinsic imaging parameters comprising a plurality of X-ray positive marks disposed in a path of said X-ray beam, said X-ray positive marks following displacement of said X-ray examination system; and

a computer using said 2D projection images and said projection geometries for constructing a 3D image therefrom of said examination subject.

2. An X-ray apparatus as claimed in claim 1 wherein said means for determining extrinsic imaging parameters include a plate mounted on one of said X-ray source and said X-ray detector outside of said path of said X-ray beam, said plate carrying a plurality of detectable items, and two stationary optical cameras having respective fields of view containing said plate.

3. An X-ray apparatus as claimed in claim 1 wherein said means for determining extrinsic imaging parameters include an image pick-up device mounted at one of said X-ray source and said X-ray receiver and a plurality of detectable items, detectable by said image pick-up device, that are stationary relative to said X-ray system.

4. An X-ray apparatus as claimed in claim 1 wherein said means for determining extrinsic imaging parameters include a transmitting and receiving arrangement for wirelessly propagating waves selected from the group consisting of electromagnetic waves and ultrasound waves, including at least transmitter disposed at one of said X-ray source and said X-ray receiver, and at least one receiver which is stationary relative to said X-ray system.

5. An X-ray apparatus as claimed in claim 1 wherein said means for determining extrinsic imaging parameters includes a transmitting and receiving arrangement for wirelessly propagating waves selected from the group consisting of electromagnetic waves and ultrasound waves, having at least one receiver disposed at one of said X-ray source and said X-ray receiver, and at least one transmitter which is stationary relative to said X-ray system.

6. An X-ray apparatus as claimed in claim 1 wherein said X-ray positive marks are disposed substantially in one plane.

7. An X-ray apparatus as claimed in claim 1 further comprising an X-ray transparent marker plate, at which said X-ray positive marks are disposed, which is disposed relative to said X-ray source so that said X-ray beam passes through said X-ray transparent marker plate in said 2D projections.

8. An X-ray apparatus as claimed in claim 7 wherein each of said 2D projections has image corners, and wherein said marker plate has at least three of said X-ray positive marks arranged thereon so that said at least three X-ray positive marks are respectively shown in different image corners of each 2D projection.

9. An X-ray apparatus as claimed in claim 7 wherein each of said 2D projections has image margins, and wherein said marker plate has at least three of said X-ray positive marks arranged thereon so that said at least three X-ray positive marks are respectively shown in different image margins of each 2D projection.

10. An X-ray apparatus as claimed in claim 1 wherein said X-ray positive marks have a shape selected from the group consisting of spheres and rods.

11. An X-ray apparatus as claimed in claim 1 wherein said X-ray source includes a diaphragm having diaphragm edges which limit a cross-section of said X-ray beam, said diaphragm edges representing an image margin in each 2D projection, and said diaphragm edges comprising linear X-ray positive marks.

12. An X-ray apparatus as claimed in claim 11 wherein said diaphragm edges have structures which are imaged in each 2D projection.

13. An X-ray apparatus as claimed in claim 1 wherein said X-ray system includes a C-arm at which said X-ray source and said X-ray receiver are mounted.

14. An X-ray apparatus as claimed in claim 1 wherein said X-ray system is a portable X-ray system.

15. A method for operating an X-ray apparatus comprising the steps of:

displacing an X-ray examination system, having an X-ray source which emits an X-ray beam from a focus and an X-ray detector on which said X-ray beam is incident, relative to an examination subject while irradiating said examination subject with said X-ray beam from a plurality of different projection angles for obtaining a plurality of 2D projection images of said examination subject respectively at said plurality of different projection angles, each of said 2D projection images having a unique projection geometry associated therewith;

determining extrinsic imaging parameters for each of said 2D projection images;

determining intrinsic imaging parameters for each of said 2D projection images by disposing a plurality of X-ray positive marks in a path of said X-ray beam, and irradiating said X-ray positive marks with X-ray beam while irradiating said examination subject from said different projection angles, and causing said X-ray positive marks to follow displacement of said X-ray examination system relative to said examination subject; and

determining the respective unique projection geometries for said 2D projection images using said extrinsic imaging parameters and said intrinsic imaging parameters, and, using said 2D projection images and said respective projection geometries, constructing a 3D image therefrom of said examination subject.

16. A method as claimed in claim 15 comprising determining said intrinsic image parameters while obtaining said 2D projection images.

17. A method as claimed in claim 15 comprising obtaining said intrinsic imaging parameters in a calibrating procedure prior to obtaining said 2D projection images.

18. A method as claimed in claim 15 comprising determining said extrinsic image parameters while obtaining said 2D projection images.

19. A method as claimed in claim 15 comprising obtaining said extrinsic imaging parameters in a calibrating procedure prior to obtaining said 2D projection images.