Method and apparatus for 3D metal and high-density artifact correction for cone-beam and fan-beam CT imaging

• US 8,023,767 B1
• Filed: 03/10/2008
• Issued: 09/20/2011
• Est. Priority Date: 03/10/2008
• Status: Active Grant

• Current Assignee: University of Rochester
• Original Assignee: University of Rochester
• Inventors: Zhang, Yan, Ning, Ruola
• Primary Examiner(s): Lu; Tom Y
• Application Number:
  US12/045,552
• Time in Patent Office: 1,289 Days
• Field of Search: 382/128, 382/131, 382/275
• US Class Current: 382/275
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition
• CPC Class Codes: A61B 6/505 for diagnosis of bone
• CPC Class Codes: A61B 6/5205 involving processing of raw data to produce diagnostic data
• CPC Class Codes: A61B 6/5258 involving detection or reduction of artifacts or noise
• CPC Class Codes: A61B 6/563 involving image data transmission via a network
• 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: G06T 2207/10081 Computed x-ray tomography [CT]
• CPC Class Codes: G06T 2207/20128 Atlas-based segmentation
• CPC Class Codes: G06T 2207/30008 Bone
• CPC Class Codes: G06T 2207/30052 Implant; Prosthesis
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/149 involving deformable models, e.g. active contour models

Abstract

A 3D metal artifacts correction technique corrects the streaking artifacts generated by titanium implants or other similar objects. A cone-beam computed tomography system is utilized to provide 3D images. A priori information (such as the shape information and the CT value) of high density sub-objects is acquired and used for later artifacts correction. An optimization process with iterations is applied to minimize the error and result in accurate reconstruction images of the object.

Claims

1. A method for producing an image of a region of interest while correcting artifacts caused by sub-objects within the region of interest, the method comprising:

(a) taking three-dimensional image data of the region of interest;

(b) providing a library of shape information and imaging characteristics of the sub-objects;

(c) using the three-dimensional image data and the library to produce images of the sub-objects in the region of interest;

(d) using an iterative optimization process to produce segmented images of the sub-objects in the region of interest;

(e) using the segmented images to produce error projections; and

(f) using the error projections to produce the image of the region of interest such that the artifacts are corrected in the image.

2. The method of claim 1, wherein step (a) is performed through computed tomography (CT).

3. The method of claim 2, wherein the computed tomography is cone beam CT.

4. The method of claim 1, wherein step (b) comprises providing the library previously formed on a storage medium.

5. The method of claim 1, wherein step (b) comprises forming the library through scanning, reconstruction and information extraction performed on the sub-objects.

6. The method of claim 1, wherein step (e) comprises determining an amount of beam hardening caused by the sub-objects.

7. The method of claim 6, wherein step (e) further comprises calculating a polynomial function of a line integral of the beam hardening.

8. The method of claim 7, wherein the polynomial is of no higher than third order.

9. The method of claim 1, wherein the region of interest comprises a region in which bone reconstruction surgery has been performed.

10. The method of claim 9, wherein the sub-objects comprise metal objects attached to bone.

11. A system for producing an image of a region of interest while correcting artifacts caused by sub-objects within the region of interest, the system comprising:

a device for supplying three-dimensional image data of the region of interest;

a device for providing a library of shape information and imaging characteristics of the sub-objects;

a processor, having access to the three-dimensional image data and the library, for;

(i) using the three-dimensional image data and the library to produce images of the sub-objects in the region of interest;

(ii) using an iterative optimization process to produce segmented images of the sub-objects in the region of interest;

(iii) using the segmented images to produce error projections; and

(iv) using the error projections to produce the image of the region of interest such that the artifacts are corrected in the image; and

an output for outputting the image of the region of interest.

12. The system of claim 11, wherein the three-dimensional image data comprise computed tomography image data.

13. The system of claim 12, wherein the computed tomography image data are cone-beam computed tomography image data.

14. The system of claim 11, wherein the library is previously formed and is provided on a storage medium.

15. The system of claim 11, wherein the processor determines an amount of beam hardening caused by the sub-objects.

16. The system of claim 15, wherein the processor further calculates a polynomial function of a line integral of the beam hardening.

17. The system of claim 16, wherein the polynomial is of no higher than third order.