Methods and systems for correcting table deflection

Patent metadata

Field	Value
Publication number	US-2016143607-A1
Application number	US-201414548846-A
Country	US
Kind code	A1
Filing date	Nov 20, 2014
Priority date	Nov 20, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

Various methods and systems are provided for estimating and compensating for table deflection in reconstructed images. In one embodiment, a method for computed tomography (CT) imaging comprises reconstructing images from data acquired during a helical CT scan where table deflection parameters are estimated and the reconstruction is adjusted based on the table deflection parameters. In this way, images may be reconstructed without artifacts caused by table deflection.

First claim

1 . A method for computed tomography (CT) imaging, comprising:
reconstructing images from data acquired during a helical CT scan where table deflection parameters are estimated and the reconstruction is adjusted based on the table deflection parameters.

2 . The method of claim 1 , wherein the table deflection parameters are estimated from image reconstructions of the helical CT scan data.

3 . The method of claim 2 , wherein the image reconstructions comprise at least two half-scan reconstructions at a same z location.

4 . The method of claim 2 , wherein the image reconstructions comprise at least two half-scan reconstructions at different z locations.

5 . The method of claim 2 , wherein estimating the table deflection parameters comprises measuring a difference in a table position between images.

6 . The method of claim 1 , wherein the table deflection parameters are estimated directly from the helical CT scan data.

7 . The method of claim 6 , wherein the helical CT scan data is rebinned to form parallel beam projections, and wherein estimating the table deflection parameters comprises measuring a difference between two of the parallel beam projections.

8 . The method of claim 1 , wherein the table deflection parameters are obtained from previously acquired scout data.

9 . The method of claim 1 , wherein the table deflection parameters are obtained from direct table sensor measurements taken during the helical CT scan.

10 . The method of claim 1 , wherein a compensation during the reconstruction is performed by shifting a back-projected image volume differently for each acquired projection view according to the table deflection parameters.

11 . The method of claim 1 , wherein a compensation during the reconstruction is performed by shifting each individual acquired projection view differently according to the table deflection parameters.

12 . The method of claim 1 , wherein the table deflection parameters are updated after the reconstruction and fed into another reconstruction with consequently higher accuracy.

13 . The method of claim 12 , wherein the table deflection parameters are estimated and compensated jointly during a model-based iterative reconstruction.

14 . A method for helical CT data acquisition, comprising:
adaptively tilting a gantry during a scan based on a table trajectory.

15 . The method of claim 14 , wherein adaptively tilting the gantry comprises tilting the gantry to maintain the gantry orthogonal to the table trajectory.

16 . The method of claim 14 , wherein the table trajectory is estimated based on a scout scan.

17 . An imaging system, comprising:
a table; a source configured to generate energy; a detector configured to detect the energy; and a processor configured to:
reconstruct images from data acquired from the detector where a deflection of the table is estimated and the reconstruction is adjusted based on the estimated deflection.

18 . The system of claim 17 , further comprising a display, and wherein the processor is further configured to display the reconstructed images on the display.

19 . The system of claim 18 , wherein the deflection is estimated based on a difference between two half-scan reconstructions comprising different views of a same position of the table.

20 . The system of claim 18 , wherein the reconstruction is adjusted by shifting a back-projected image volume differently for each acquired projection view according to the estimated deflection.

Assignees

• Gen Electric
• Univ Notre Dame Du Lac

Inventors

• Cao Guangzhi
• Hsieh Jiang
• Thibault Jean-Baptiste
• Fan Jiahua
• Sauer Ken D

Classifications

• G06T12/00

  Tomographic reconstruction from projections · CPC title

• G06T12/20

  Inverse problem, i.e. transformations from projection space into object space · CPC title

• A61B6/0407

  Supports, e.g. tables or beds, for the body or parts of the body · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/027

  characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral · CPC title