Computed tomography

• US 6,765,981 B2
• Filed: 07/31/2002
• Issued: 07/20/2004
• Est. Priority Date: 07/31/2002
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Heumann, John M
• Primary Examiner(s): BRUCE, DAVID VERNON
• Application Number:
  US10/209,378
• Publication Number:
  US 20040022348A1
• Time in Patent Office: 720 Days
• Field of Search: 378/4, 378/8, 378/15, 378/19, 378/901
• US Class Current: 378/4
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

A system and method of computed tomography is disclosed. The method includes acquiring at least one projection but less than all projections to be used in reconstruction of an unknown object and processing the at least one projection for reconstruction of the unknown object. After processing each projection is discarded. Projections are acquired until all projections have been processed. An estimate of the unknown object may be generated during the processing of each of the projections.

Claims

1. A method of computed tomography of an unknown object comprising:

acquiring at least one projection, but less than all projections to be used in reconstruction of the unknown object; and

revising an estimate of the unknown object using the at least one projection to obtain a new estimate.

2. The method of claim 1, further comprising:

acquiring another at least one projection; and

revising the new estimate of the unknown object using the another at least one projection.

3. The method of claim 1, farther comprising acquiring another at least one projection concurrently with revising the estimate of the unknown object.

4. The method of claim 1, wherein revising an estimate includes:

calculating a predicted projection using the estimate of the unknown object;

calculating an error between the acquired projection and the predicted projection; and

applying an update rule to revise the current estimate of the unknown object using the calculated error to obtain the new estimate.

5. The method of claim 1, wherein revising an estimate includes choosing a step size for selection of a subsequent projection.

6. The method of claim 1 further comprising acquiring another at least one projection concurrently with acquiring the at least one projection, and revising the estimate of the unknown object using the another at least one projection to obtain another new estimate concurrently with revising the estimate of the unknown object using the at least one projection to obtain the new estimate.

7. The method of claim 1 further comprising setting an initial estimate of the unknown object.

8. The method of claim 1, wherein revising an estimate includes using a series reconstruction method.

9. The method of claim 1, further comprising discarding the at least one projection.

10. The method of claim 1, wherein acquiring at least one projection includes acquiring a pair of projections separated by approximately 180 degrees.

11. A method of computed tomography of an unknown object comprising:

acquiring at least one projection, but less than all projections to be used in reconstruction of the unknown object; and

processing the at least one projection for reconstruction of the unknown object.

12. The method of claim 11, further comprising:

acquiring another at least one projection; and

processing the another at least one projection for reconstruction of the unknown object.

13. The method of claim 11, further comprising acquiring another at least one projection concurrently with processing the at least one projection for reconstruction of the unknown object.

14. The method of claim 11, wherein processing each projection includes:

calculating a predicted projection using an estimate of the unknown object;

calculating an error between the acquired projection and the predicted projection; and

applying an update rule to revise the estimate of the unknown object using the calculated error to obtain a new estimate.

15. The method of claim 11, wherein processing the at least one projection includes setting a step size for selection of a subsequent projection.

16. The method of claim 11 further comprising acquiring another at least one projection concurrently with acquiring the at least one projection, and processing the another at least one projection for reconstruction of the unknown object concurrently with processing the at least one projection for reconstruction of the unknown object.

17. The method of claim 11 further comprising setting an initial estimate of the unknown object.

18. The method of claim 11, wherein processing each projection includes using a series reconstruction method.

19. The method of claim 11, wherein acquiring at least one projection includes acquiring two projections separated by approximately 180 degrees.

20. A computed tomography system comprising:

means for acquiring at least one projection, but less than all projections to be used in reconstruction of an unknown object; and

means for processing the at least one projection for reconstruction of the unknown object.