Post acquisition calibration

• US 9,931,098 B2
• Filed: 04/14/2016
• Issued: 04/03/2018
• Est. Priority Date: 04/14/2016
• Status: Active Grant

• Current Assignee: CareStream Health Incorporated
• Original Assignee: CareStream Health Incorporated
• Inventors: West, Frank, Packard, Nathan J.
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): LEMIEUX, IAN L
• Application Number:
  US15/098,610
• Publication Number:
  US 20170296137A1
• Time in Patent Office: 719 Days
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4007 characterised by using a plurality of source units
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: A61B 6/583 using calibration phantoms
• 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 11/008 Specific post-processing after tomographic reconstruction, e.g. voxelisation, metal artifact correction
• CPC Class Codes: G06T 2207/10081 Computed x-ray tomography [CT]
• CPC Class Codes: G06T 2207/30168 Image quality inspection

Abstract

A method of operating a tomographic imaging system whereby a plurality of radiographic images of an object are captured at a first orientation of the system'"'"'s source and detector. After the radiographic images are captured and stored, geometric calibration data for the system is measured, corresponding to the first orientation of the system. A three dimensional image of the object is reconstructed using the measured geometric calibration data corresponding to the first orientation.

Claims

1. A method of operating tomographic imaging systems that each include a source and a detector, the method comprising:

capturing a plurality of first projection images of a first patient using the source and detector of a first imaging system at a first orientation of the source and detector;

after the step of capturing, performing a calibration scan of a calibration object using the source and detector of the first imaging system to generate first geometric calibration data corresponding to the first orientation;

capturing a plurality of second projection images of a second patient using the source and detector of a second imaging system at an orientation similar to the first orientation within a predetermined deviation; and

reconstructing a three dimensional image of the second patient using the captured plurality of the second projection images and the generated first geometric calibration data corresponding to the first orientation.

2. The method of claim 1, further comprising determining the first orientation based on an angle of an imaging axis of the source and detector of the first imaging system.

3. The method of claim 2, wherein the step of performing a calibration scan comprises scanning a phantom using the source and detector of the first imaging system at the first orientation.

4. The method of claim 3, wherein the step of performing a calibration scan comprises measuring an amount of deflection of the source and detector of the first imaging system at the first orientation to generate the geometric calibration data.

5. The method of claim 1, further comprising determining that acceptable geometric calibration data is not available before the step of performing a calibration scan.

6. The method of claim 1, further comprising:

transferring the plurality of second projection images to a processing system; and

transferring the generated first geometric calibration data to the processing system,

wherein the step of reconstructing is performed by the processing system.

7. A method of operating a tomographic imaging system that includes a source and a detector, the method comprising:

performing a calibration scan of a calibration object using the source and the detector of the tomographic imaging system to generate first geometric calibration data;

capturing a plurality of projection images of a patient at a first orientation of the source and the detector;

reconstructing a first 3-D volume image of the patient using the plurality of projection images of the patient and the first geometric calibration data;

determining that the first reconstructed 3-D volume image of the patient does not satisfy a predetermined quality metric;

after the step of determining, searching for and finding in a database second geometric calibration data that corresponds within a predetermined range to the first orientation of the source and the detector, wherein the second geometric calibration was generated by an imaging system different than the tomographic imaging system; and

reconstructing a second 3-D volume image of the patient using the plurality of projection images of the patient and the found second geometric calibration data.

8. The method of claim 7, further comprising searching for and finding in the database third geometric calibration data generated by another imaging system different than the tomographic imaging system and reconstructing a third 3-D volume image of the patient using the plurality of projection images of the patient and the third geometric calibration data.

9. The method of claim 7, further comprising determining the first orientation based on at least two angular coordinates, wherein the at least two angular coordinates are based upon two separate and orthogonal axes.

10. The method of claim 9, further comprising scanning a phantom using the tomographic imaging system to generate the first geometric calibration data.

11. The method of claim 7, wherein the steps of reconstructing the first 3-D volume image and the step of reconstructing the second 3-D volume image are performed by a processing system accessible by the tomographic imaging system including transferring the plurality of projection images to the processing system and transferring the second geometric calibration data to the processing system.

12. A method of operating a first imaging system that includes a source and a detector, the method comprising:

accessing a plurality of stored radiographic projection images of an object;

determining an orientation of a second imaging system that was used to capture the plurality of stored radiographic projection images;

after the steps of accessing and determining, obtaining geometric calibration data for the first imaging system based on the determined orientation of the second imaging system; and

reconstructing a 3-D image of the object using the plurality of stored radiographic projection images and the obtained geometric calibration data.

13. The method of claim 12, further comprising determining that a geometry of the first imaging deviates from a geometry of the second imaging system within an acceptable margin.

14. The method of claim 12, further comprising determining the orientation of the second imaging system based on at least two angular coordinates, wherein the at least two angular coordinates are based upon two separate and orthogonal axes.

15. The method of claim 12, wherein the step of obtaining geometric calibration data for the first imaging system comprises scanning a phantom in the first imaging system after positioning the source and detector according to the determined orientation of the second imaging system.

16. The method of claim 12, further comprising accessing a 3-D image of the object that was reconstructed by the second imaging system including determining that the accessed 3-D image does not satisfy a selected quality criterion.

17. A computer implemented method comprising:

receiving a plurality of radiographic projection images of an object captured by a first imaging system;

determining an orientation of the first imaging system used to capture the plurality of radiographic projection images;

receiving geometric calibration data corresponding to a geometry of the first imaging system and corresponding to the orientation used by the first imaging system to capture the plurality of radiographic projection images, wherein the geometric calibration data is generated by a second imaging system; and

reconstructing a 3-D image of the object using the received plurality of radiographic projection images and the received geometric calibration data.

18. The method of claim 17, further comprising determining that a geometry and orientation used to generate the geometric calibration data by the second imaging system deviates within a predetermined margin from the geometry and orientation used by the first imaging system to capture the plurality of radiographic projection images, prior to the step of reconstructing.

19. The method of claim 17, further comprising searching over a network for, or sending a request over a network for, the received geometric calibration data.