Method for generating an image by means of a tomography capable x-ray device with multi-row x-ray detector array

• US 20040141581A1
• Filed: 09/26/2003
• Published: 07/22/2004
• Est. Priority Date: 09/27/2002
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Bruder, Herbert, Flohr, Thomas, Stierstorfer, Karl, Tam, Kwok
• Granted Patent: US 6,928,137 B2
• Time in Patent Office: Days
• US Class Current: 378/4
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating

Abstract

In a method for generating an image of an examination subject with a tomography-capable X-ray device, particularly a computed tomography device, having a multi-row X-ray detector array, an X-ray radiator that rotates about a system axis and emits a conical x-ray beam, and a positioning device by means of which the subject is positionable relative to the X-ray radiator in different z-positions in a direction parallel to the system axis, the image is reconstructed from the raw data that are generated from the X-ray radiator. Raw data are generated from both a rotation scan and a linear scan. In the linear scan, all transmission values for the image reconstruction are acquired in one continuous linear scanning movement, so that the rotation scan can be picked up while the X-ray radiator is in continuous rotation. A topogram that is executed prior to the actual rotation scan for the purpose of selecting a region of interest of the subject for the subsequent rotation scan can be utilized as a linear measurement dataset. A particularly rapid acquisition of initial data for the subsequent 3D image reconstruction occurs.

Claims

1. A method for generating an image of an examination subject using a tomography-capable X-ray device having a multi-row X-ray detector array, an X-ray radiator rotatable around a system axis that emits a conical X-ray beam, and a positioning device adapted to receive an examination subject thereon for positioning the subject in a direction parallel to said system axis at different positions parallel to the system axis relative to the X-ray radiator, comprising the steps of:

generating raw data by the radiating said examination subject with said X-ray beam in a rotation scan to acquire a plurality of projections during at least one revolution or partial revolution of said X-ray radiator around the subject, and by a linear scan wherein transmission values are acquired at different positions of said subject parallel to said system axis, without rotation of said X-ray radiator, with all of said transmission values generated by said linear scan being acquired in a continuous linear scanning movement; and

generating an image of said subject from said raw data generated by said rotation scan and said linear scan.

2. A method as claimed in claim 1 comprising acquiring the transmission values during the continuous linear scanning movement in direct succession, with no intermediate rotation of said X-ray radiator.

3. A method as claimed in claim 1 comprising acquiring all of said projections by said rotation scan in one continuous rotational movement of the X-ray radiator.

4. A method as claimed in claim 1 comprising, during said rotation scan, successively moving said subject on said positioning device to respectively different positions in said direction parallel to said system axis, and acquiring a plurality of projections at each of said positions with at least one revolution of the X-ray radiator around the subject.

5. A method as claimed in claim 1 comprising, in said rotational scan, acquiring a plurality of projections at a single position of said subject in said direction parallel to said system axis during at least one revolution of the X-ray radiator around the subject, and employing a flat detector as said multi-row X-ray detector array.

6. A method as claimed in claim 1 comprising conducting said linear scan as a topogram of said subject.

7. A method for generating an image of an examination subject using a tomography-capable X-ray device having a multi-row X-ray detector array, an X-ray radiator rotatable around a system axis that emits a conical X-ray beam, and a positioning device adapted to receive an examination subject thereon for positioning the subject in a direction parallel to said system axis at different positions parallel to the system axis relative to the X-ray radiator, comprising the steps of:

acquiring a topogram of the subject by measuring transmission values of the subject at different positions of the subject along said direction parallel to the system axis, without rotation of said X-ray radiator;

displaying said topogram at a display unit and selecting a relevant region of the subject in the displayed tomogram;

storing said topogram;

obtaining raw data of the examination subject in a rotation scan by acquiring a plurality of projections of the subject during at least one revolution or partial revolution of the X-ray radiator around the subject; and

reconstructing an image of the subject from the stored topogram in combination with the raw data acquired during the rotation scan.

8. A method as claimed in claim 7 comprising executing said rotation scan to cover at least said relevant region.

9. A method as claimed in claim 7 comprising acquiring all of the projections in said rotation scan in one continuous rotational movement of the X-ray radiator.