Method for metal artifact avoidance in x-ray imaging

1. A method for metal artifact avoidance in 3D x-ray imaging, the method comprising:

determining a 3D location of metal in an object or volume of interest to be scanned;

estimating a source-detector orbit that will reduce severity of metal artifacts, wherein the source-detector orbit is a non-circular orbit that is defined by a tilt angle and a rotation angle of a gantry arm are varied during a scanning operation, wherein the estimating the source-detector orbit further comprises computing an objective function that is based on the 3D location of the metal that was determined, wherein the objective function describes a spectral shift that is associated with metal artifacts in 3D image reconstruction;

moving an imaging system to locations consistent with the source-detector orbit that was estimated or to locations close to the source-detector orbit that was estimated and within existing spatial constraints; and

scanning the object or the volume of interest according to the source-detector orbit.

2. The method of claim 1 , wherein the determining further comprises one or more of the following: performing an initial 3D scan of the object or volume of interest, acquiring one or more x-ray projection images of the object or volume of interest, or using a tracking system comprising one or more cameras or electromagnetic trackers to locate the metal.

3. The method of claim 1 , wherein the source-detector orbit comprises a position and orientation of an x-ray source and a detector for projections to be acquired in the 3D x-ray imaging.

4. The method of claim 1 , wherein the objective function is further based on one or more of: a range in a metric map along a rotation axis of a gantry, a standard deviation of a metric map along a rotation axis of a gantry, a maximum of the metric map along the rotation axis of the gantry, a sum of metric maps for a range of rotation angles of the gantry.

5. The method of claim 1 , wherein the severity of metal artifacts is reduced compared to a circular path in a plane perpendicular to a long axis of the object.

6. The method of claim 1 , wherein the scanning further comprises acquiring a plurality of x-ray projections along the source-detector orbit and forming a 3D image reconstruction of the object.

7. The method of claim 6 , wherein the forming the 3D image reconstruction further comprises performing one or more 3D image reconstruction algorithms comprising 3D filtered backprojection, other analytical methods for 3D image reconstruction, model-based image reconstruction, deep-learning, or neural network reconstruction.

8. A 3-D x-ray imaging system comprising:

a 3-D x-ray imaging device comprising a gantry that is movable in a plurality of tilt angles along a tilt axis and a plurality of rotation angles along a rotation axis; and

a hardware-processor configured to execute instructions comprising:

determining a 3D location of metal in an object or volume of interest to be scanned;

estimating a source-detector orbit that will reduce severity of metal artifacts, wherein the source-detector orbit is a non-circular orbit that is defined by a tilt angle and a rotation angle of a gantry arm are varied during a scanning operation, wherein the estimating the source-detector orbit further comprises computing an objective function that is based on the 3D location of the metal that was determined, wherein the objective function describes a spectral shift that is associated with metal artifacts in 3D image reconstruction;

moving an imaging system to locations consistent with the source-detector orbit that was estimated or to locations close to the source-detector orbit that was estimated and within existing spatial constraints; and

scanning the object or the volume of interest according to the source-detector orbit.

9. The 3-D x-ray imaging system of claim 8 , wherein the determining further comprises one or more of the following: performing an initial 3D scan of the object or volume of interest, acquiring one or more x-ray projection images of the object or volume of interest, or using a tracking system comprising one or more cameras or electromagnetic trackers to locate the metal.

10. The 3-D x-ray imaging system of claim 8 , wherein the source-detector orbit comprises a position and orientation of an x-ray source and a detector for projections to be acquired in 3D x-ray imaging.

11. The 3-D x-ray imaging system of claim 8 , wherein the objective function is further based on one or more of: a range of a metric map along a rotation axis of a gantry, a standard deviation of a metric map along a rotation axis of a gantry, a maximum of the metric map along the rotation axis of the gantry, a sum of metric maps for a range of rotation angles of the gantry.

12. The 3-D x-ray imaging system of claim 8 , wherein the severity of metal artifacts is reduced compared to a circular path in a plane perpendicular to a long axis of the object.

13. The 3-D x-ray imaging system of claim 8 , wherein the scanning further comprises acquiring a plurality of x-ray projections along the source-detector orbit and forming a 3D image reconstruction of the object.

14. The 3-D x-ray imaging system of claim 13 , wherein the forming the 3D image reconstruction further comprises performing one or more 3D image reconstruction algorithms comprising 3D filtered backprojection, other analytical methods for 3D image reconstruction, model-based image reconstruction, deep-learning, or neural network reconstruction.

15. A non-transitory computer readable medium comprising instructions that when executed by a hardware processor are configured to perform a method for metal artifact avoidance in 3D x-ray imaging, the method comprising:

determining a 3D location of metal in an object or volume of interest to be scanned;

estimating a source-detector orbit that will reduce severity of metal artifacts, wherein the source-detector orbit is a non-circular orbit that is defined by a tilt angle and a rotation angle of a gantry arm are varied during a scanning operation, wherein the estimating the source-detector orbit further comprises computing an objective function that is based on the 3D location of the metal that was determined, wherein the objective function describes a spectral shift that is associated with metal artifacts in 3D image reconstruction;

moving an imaging system to locations consistent with the source-detector orbit that was estimated or to locations close to the source-detector orbit that was estimated and within existing spatial constraints; and

scanning the object or the volume of interest according to the source-detector orbit.

16. The non-transitory computer readable medium of claim 15 , wherein the determining further comprises one or more of the following: performing an initial 3D scan of the object or volume of interest, acquiring one or more x-ray projection images of the object or volume of interest, or using a tracking system comprising one or more cameras or electromagnetic trackers to locate the metal.

17. The non-transitory computer readable medium of claim 15 , wherein the source-detector orbit comprises a position and orientation of an x-ray source and a detector for projections to be acquired in the 3D x-ray imaging.

18. The non-transitory computer readable medium of claim 15 , wherein the objective function is further based on one or more of: a range in a metric map along a rotation axis of a gantry, a standard deviation of a metric map along a rotation axis of a gantry, a maximum of the metric map along the rotation axis of the gantry, a sum of metric maps for a range of rotation angles of the gantry.

19. The non-transitory computer readable medium of claim 15 , wherein the severity of metal artifacts is reduced compared to a circular path in a plane perpendicular to a long axis of the object.

20. The non-transitory computer readable medium of claim 15 , wherein the scanning further comprises acquiring a plurality of x-ray projections along the source-detector orbit and forming a 3D image reconstruction of the object.