Systems and methods for real-time tumor tracking

• US 10,043,284 B2
• Filed: 05/07/2014
• Issued: 08/07/2018
• Est. Priority Date: 05/07/2014
• Status: Active Grant

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Inventors: Newell, Laurence J., Phillips, Stephen, Kraft, Raymond, Lin, Sun-Kai
• Primary Examiner(s): Wang, Carol
• Application Number:
  US14/272,382
• Publication Number:
  US 20150324967A1
• Time in Patent Office: 1,553 Days
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: G06T 2207/30081 Prostate
• CPC Class Codes: G06T 2207/30096 Tumor; Lesion
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06T 7/277 involving stochastic approaches, e.g. using Kalman filters
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80

Abstract

Various embodiments disclose systems and methods for tracking regions (e.g., tumor locations) within living organisms. Some embodiments provide real-time, highly accurate, low latency measurements of tumor location even as the tumor moves with internal body motions. Such measurements may be suitable for closed-loop radiation delivery applications where radiation therapy may be continuously guided to the tumor site even as the tumor moves. Tumor motion may be associated with periodic motion (e.g., respiratory, cardiac) or aperiodic motion (e.g., gross patient motion, internal bowel motion). Various embodiments facilitate accurate radiation delivery to tumor sites exhibiting significant motion, e.g., lung, breast, and liver tumors.

Claims

1. A computer-implemented method, comprising:

determining a first position of a first fiducial of a plurality of fiducials, the plurality of fiducials located in or on a portion of a human body, the plurality of fiducials each associated with a plurality of preliminary positions;

predicting a first plurality of positions associated with the plurality of fiducials based upon the determined position of the first fiducial and the plurality of preliminary positions;

determining a first target position based upon the first plurality of positions;

determining a second position of a second fiducial of the plurality of fiducials;

predicting a second plurality of positions associated with the plurality of fiducials based upon the determined second position of the second fiducial;

determining a second target position based upon the second plurality of positions;

determining a relation to a boundary based upon the first target position and the second target position, wherein the relation to the boundary comprises a determination, during radiation therapy, that a centroid of the plurality of fiducials will traverse the boundary at a future time;

associating a timestamp with the future time at which the centroid of the plurality of fiducials will traverse the boundary; and

interrupting the radiation therapy at the future time associated with the timestamp.

2. The computer-implemented method of claim 1, wherein the first target position corresponds to a first centroid position and the second target position corresponds to a second centroid position.

3. The computer-implemented method of claim 1, wherein the first target position corresponds to a first centroid position by an offset defined in a patient plan.

4. The computer-implemented method of claim 1, the method further comprising maintaining a rigid body model of the set of the plurality of fiducials, and wherein determining a relation to a boundary comprises determining a centroid velocity.

5. The computer-implemented method of claim 1, wherein the relation to the boundary comprises a determination that a centroid of the plurality of fiducials has traversed the boundary.

6. The computer-implemented method of claim 1, the method further comprising determining an initial target orientation using a weighted, rigid, Procrustes fit.

7. The computer-implemented method of claim 1, the method further comprising performing a dynamic calibration measurement of the first fiducial to mitigate an effect of a LINAC gantry on localization accuracy, the dynamic calibration measurement comprising a measurement of the mutual inductance between all coils in an array.

8. The computer-implemented method of claim 1, further comprising:

determining a third position of a third fiducial of the plurality of fiducials; and

predicting a third plurality of positions associated with the plurality of fiducials based on a first predicted position of the second plurality of positions associated with the third fiducial.

9. The computer-implemented method of claim 1 wherein predicting the second plurality of positions associated with the plurality of fiducials is further based on a comparison between (1) a first predicted position of the first plurality of positions associated with the second fiducial and (2) the determined second position of the second fiducial.

10. A non-transitory computer-readable medium comprising instructions executable by one or more processors to perform a method comprising:

determining a first position of a first fiducial of a plurality of fiducials, the plurality of fiducials located in or on a portion of a human body;

predicting a first plurality of positions associated with the plurality of fiducials based upon the determined position of the first fiducial;

determining a first target position based upon the first plurality of positions;

determining a second position of a second fiducial of the plurality of fiducials;

predicting a second plurality of positions associated with the plurality of fiducials based upon the determined second position of the second fiducial;

determining a second target position based upon the second plurality of positions;

determining a relation to a boundary based upon the first target position and the second target position, wherein the relation to the boundary comprises an inference, during treatment, that a centroid of the plurality of fiducials will traverse the boundary within a future period of time;

associating a timestamp with a minimum time to boundary crossing of the future period of time; and

interrupting treatment at the minimum time to boundary crossing associated with the timestamp.

11. The non-transitory computer-readable medium of claim 10, wherein the first target position corresponds to a first centroid position and the second target position corresponds to a second centroid position.

12. The non-transitory computer-readable medium of claim 10, wherein the first target position corresponds to a first centroid position by an offset defined in a patient plan.

13. The non-transitory computer-readable medium of claim 10, the method further comprising maintaining a rigid body model of the set of the plurality of fiducials, and wherein determining a relation to a boundary comprises determining a centroid velocity.

14. The non-transitory computer-readable medium of claim 10, wherein the relation to the boundary comprises a determination that a centroid of the plurality of fiducials has traversed the boundary.

15. The non-transitory computer-readable medium of claim 10, the method further comprising determining an initial target orientation using a weighted, rigid, Procrustes fit.

16. The non-transitory computer-readable medium of claim 10, the method further comprising performing a dynamic calibration measurement of the first fiducial to mitigate an effect of a LINAC gantry on localization accuracy, the dynamic calibration measurement comprising a measurement of the mutual inductance between all coils in an array.

17. A computer system comprising:

at least one processor;

at least one memory, the at least one memory comprising instructions configured to cause the computer system to perform a method using the at least one processor, the method comprising;

determining a first position of a first fiducial of a plurality of fiducials, the plurality of fiducials located in or on a portion of a human body;

predicting a first plurality of positions associated with the plurality of fiducials based upon the determined position of the first fiducial;

determining a first target position based upon the first plurality of positions;

determining a second position of a second fiducial of the plurality of fiducials;

predicting a second plurality of positions associated with the plurality of fiducials based upon the determined second position of the second fiducial;

determining a second target position based upon the second plurality of positions;

determining, during radiation therapy, a relation to a boundary based upon the first target position and the second target position, wherein the relation to the boundary comprises a prediction that a centroid of the plurality of fiducials will traverse the boundary at a future time;

associating a timestamp with the future time at which the centroid of the plurality of fiducials will traverse the boundary; and

interrupting the radiation therapy at the future time.

18. The computer system of claim 17, wherein the first target position corresponds to a first centroid position and the second target position corresponds to a second centroid position.

19. The computer system of claim 17, wherein the first target position corresponds to a first centroid position by an offset defined in a patient plan.

20. The computer system of claim 17, the method further comprising maintaining a rigid body model of the set of the plurality of fiducials, and wherein determining a relation to a boundary comprises determining a centroid velocity.

21. The computer system of claim 17, wherein the relation to the boundary comprises a determination that a centroid of the plurality of fiducials has traversed the boundary.

22. The computer system of claim 17, the method further comprising determining an initial target orientation using a weighted, rigid, Procrustes fit.

23. The computer system of claim 17, the method further comprising performing a dynamic calibration measurement of the first fiducial to mitigate an effect of a LINAC gantry on localization accuracy, the dynamic calibration measurement comprising a measurement of the mutual inductance between all coils in an array.