Method and system for reconstructing an image from projection data acquired by a cone beam computed tomography system

• US 6,850,586 B2
• Filed: 03/11/2004
• Issued: 02/01/2005
• Est. Priority Date: 09/26/2002
• Status: Active Grant

• Current Assignee: Carestream Dental Technology Topco Limited
• Original Assignee: Eastman Kodak Company
• Inventors: Cahill, Nathan D.
• Primary Examiner(s): BRUCE, DAVID VERNON
• Application Number:
  US10/797,980
• Publication Number:
  US 20040170248A1
• Time in Patent Office: 327 Days
• Field of Search: 378/4, 378/8, 378/15, 378/19, 378/901
• US Class Current: 378/8
• 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: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 2223/612 biological material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

A method and system for reconstructing a three-dimensional image of an object from cone beam projection data. The method comprising the steps of: acquiring the projection data, wherein the projection data comprises a set of cone beam projection images; selecting at least one cone beam projection image; identifying a region of interest within each selected cone beam projection image; defining a three-dimensional lattice of points, wherein the projection into each selected cone beam projection image of the points in the three-dimensional lattice provides a sampling of the identified region of interest in the corresponding selected cone beam projection image; and, reconstructing an image of the object at each point in the three-dimensional lattice to form a three-dimensional image of the object.

Claims

1. A method for reconstructing a three-dimensional image of an object from cone beam projection data, the method comprising the steps of:

acquiring the cone beam projection data, the cone beam projection data comprising a plurality of cone beam projection images;

determining a three-dimensional reconstruction region using a region of interest identified in at least one of the plurality of cone beam projection images, the three-dimensional reconstruction region being defined by a plurality of points; and

reconstructing the image at each of the plurality of points to form the three-dimensional image of the region of interest.

2. The method of claim 1, wherein the step of determining comprises the steps of:

identifying the region of interest within at least two of the plurality of projection images; and

projecting each identified region of interest through at least a portion of the object to identify the three-dimensional reconstruction region.

3. The method of claim 1, wherein the cone beam projection data is acquired by operating a source and a detector arrangement at a plurality of source positions along a scan path that encircles the region of interest of the object.

4. The method of claim 1, wherein a source and detector arrangement rotate about an axis of rotation and the projection images are acquired at angular increments about the axis of rotation, the step of identifying the regions of interest comprises the steps of:

selecting, from the plurality of projection images, a first projection image at a predetermined angle; and

selecting, from the plurality of projection images, a second projection image at an angle ninety degrees beyond the predetermined angle.

5. The method of claim 1, wherein the step of determining comprises the steps of:

identifying a region of interest within a plurality of projection images;

projecting each identified region of interest to a source position corresponding with the associated projection image to define a three-dimensional projected cone; and

sampling the intersection of the projected cones to determine a three-dimensional reconstruction region defined by a plurality of points.

6. The method of claim 5, wherein the step of identifying a region of interest comprises the step of identifying regions of interest with two cone projection images disposed at ninety degrees from each other.

7. The method of claim 1, wherein the step of determining comprises the steps of:

identifying the region of interest within one of the plurality of projection images; and

projecting the identified region of interest through at least a portion of the object region to fine the three-dimensional reconstruction region.

8. The method of claim 1, wherein the step of determining comprises the steps of:

identifying a region of interest within a first one of the plurality of projection images;

projecting the identified region of interest to a source position corresponding with the first one of the plurality of projection images to define a first three-dimensional projection cone;

projecting a second one of the plurality of projection images to a source position corresponding with the second one of the plurality of projection images to define a second three-dimensional projection cone; and

using the first and second projected cones to determine a three-dimensional reconstruction region defined by a plurality of points.

9. A computer storage product having at least one computer storage medium having instructions stored therein causing one or more computers to perform the method of claim 1.