Multi-phase registration of 2-D X-ray images to 3-D volume studies
View Patent ↗A method for registering 2-D radiographic images to 3-D volume studies includes generating digitally reconstructed radiographs (DRRs) from a 3-D volume study. The DRR's are used as reference images to register a patient's position during image-guided radiosurgery. Stereoscopic X-rays of the patient are acquired during treatment, and multi-phase registration is used to register the DRRs with the X-ray images in two or more projections.
1. A method, comprising:
estimating, by a processing device, transformation parameters between a 2-D projection of a volume and a 2-D reference image of the volume in a plurality of search-phases, the estimating comprising:
estimating in-plane transformation parameters between the 2-D projection of the volume and a 2-D reference image generated from 3-D scan data of the volume in a first search-phase; and
estimating out-of-plane rotation parameters between the 2-D projection and a plurality of 2-D reference images generated from the 3-D scan data of the volume in a second search-phase; and
searching, by the processing device, for 2-D transformation parameters in each of the plurality of search-phases using combinations of search techniques and similarity measures in each search-phase.
2. The method of claim 1 , further comprising:
repeating a search for one or more transformation parameters to achieve a desired registration accuracy between the 2-D projection of the volume and the 2-D reference image of the volume.
3. The method of claim 2 , wherein estimating the transformation parameters between the 2-D projection of the volume and the 2-D reference image of the volume comprises: estimating the in-plane transformation parameters between the 2-D projection of the volume and a 2-D reference image generated from 3-D scan data of the volume, using a first similarity measure and a first search method in each of two or more projections; and estimating the out-of-plane rotation parameters between the 2-D projection and a plurality of 2-D reference images generated from the 3-D scan data of the volume, using a second similarity measure and a second search method in each of the two or more projections.
4. The method of claim 3 , wherein repeating a search for one or more transformation parameters to achieve a desired registration accuracy between the 2-D projection of the volume and the 2-D reference image of the volume comprises refining the in-plane transformation parameters and the out-of-plane rotation parameters using the second similarity measure and at least a third search method in each of the two or more projections.
5. The method of claim 4 , wherein the out-of-plane rotation parameters in each of the two or more projections comprise two out-of-plane rotation parameters, and wherein the second search method comprises a 1-D search in each of the two or more projections.
6. The method of claim 5 , wherein the 1-D search searches the two out-of-plane rotation parameters in each of the two or more projections.
7. The method of claim 5 , wherein one of the out-of-plane rotation parameters in each projection comprises one of the in-plane rotation parameters in another projection, and wherein the 1-D search searches only one of the two out-of-plane rotation parameters in each of the two or more projections.
8. The method of claim 5 , wherein the in-plane transformation parameters comprise two in-plane translations and one in-plane rotation in each projection, wherein the second similarity measure comprises an optimized pattern intensity similarity measure, and wherein refining the in-plane transformation parameters in each projection comprises: refining the in-plane translation parameters in each projection using 2-D sub-pixel matching; and refining the in-plane rotation parameter in each projection using the 1-D search.
9. The method of claim 8 , further comprising: determining whether the in-plane translation parameters and the in-plane rotation parameters in each projection have enough accuracy to achieve a desired registration accuracy; and repeating the method of claim 8 if the in-plane translation parameters and the in-plane rotation parameters do not have enough accuracy to achieve the desired registration accuracy; else refining the out-of-plane rotation parameters in each projection using the 1-D search.
10. The method of claim 5 , wherein the in-plane transformation parameters comprise two in-plane translations and one in-plane rotation in each projection, wherein the second similarity measure comprises an optimized pattern intensity similarity measure, and wherein refining the in-plane transformation parameters and the out-of-plane rotation parameters comprises: refining the in-plane translation parameters in each projection using a steepest descent minimization; refining the in-plane rotation parameters in each projection using the steepest descent minimization; and refining the out-of-plane rotation parameters in each projection using the 1-D search.
11. The method of claim 10 , further comprising: determining whether the in-plane translation parameters and the in-plane rotation parameters in each projection have enough accuracy to achieve a desired registration accuracy; and repeating the method of claim 10 if the in-plane translation parameters and the in-plane rotation parameters do not have enough accuracy to achieve the desired registration accuracy; else refining the out-of-plane rotation parameters in each projection using the 1-D search.
12. The method of claim 3 , wherein the first similarity measure comprises a simple similarity measure and the first search method comprises a hierarchical search.
13. The method of claim 12 , wherein the hierarchical search comprises 3-parameter multi-level matching.
14. The method of claim 12 , wherein the first similarity measure is one of a sum of squared differences (SSD) measure and a sum of absolute differences (SAD) measure.
15. The method of claim 1 , further comprising converting the transformation parameters into a 3-D rigid transformation of the volume.
16. An article of manufacture, including machine-accessible instructions that when accessed by a data processing system, cause the data processing system to perform a method, comprising:
estimating transformation parameters between a 2-D projection of a volume and a 2-D reference image of the volume in a plurality of search-phases, the estimating comprising:
estimating in-plane transformation parameters between the 2-D projection of the volume and a 2-D reference image generated from 3-D scan data of the volume in a first search-phase; and
estimating out-of-plane rotation parameters between the 2-D projection and a plurality of 2-D reference images generated from the 3-D scan data of the volume in a second search-phase; and
searching for 2-D transformation parameters in each of the plurality of search-phases using combinations of search techniques and similarity measures in each search phase.
17. The article of manufacture of claim 16 , further comprising repeating a search for one or more transformation parameters to achieve a desired registration accuracy between the 2-D projection of the volume and the 2-D reference image of the volume.
18. The article of manufacture of claim 17 , wherein estimating the transformation parameters between the 2-D projection of the volume and the 2-D reference image of the volume comprises:
estimating the in-plane transformation parameters between the 2-D projection of the volume and a 2-D reference image generated from 3-D scan data of the volume, using a first similarity measure and a first search method in each of two or more projections; and
estimating the out-of-plane rotation parameters between the 2-D projection and a plurality of 2-D reference images generated from the 3-D scan data of the volume, using a second similarity measure and a second search method in each of the two or more projections.
19. The article of manufacture of claim 18 , the method further comprising refining the in-plane transformation parameters and the out-of-plane rotation parameters using the second similarity measure and at least a third search method in each of the two or more projections.
20. The article of manufacture of claim 19 , wherein the out-of-plane rotation parameters in each of the two or more projections comprise two out-of-plane rotation parameters, and wherein the second search method comprises a 1-D search in each of the two or more projections.
21. The article of manufacture of claim 20 , wherein the 1-D search searches the two out-of-plane rotation parameters in each of the two or more projections.
22. The article of manufacture of claim 20 , wherein one of the out-of-plane rotation parameters in each projection comprises one of the in-plane rotation parameters in another projection, and wherein the 1-D search searches only one of the two out-of-plane rotation parameters in each of the two or more projections.
23. The article of manufacture of claim 20 , wherein the in-plane transformation parameters comprise two in-plane translations and one in-plane rotation in each projection, wherein the second similarity measure comprises an optimized pattern intensity similarity measure, and wherein refining the in-plane transformation parameters in each projection comprises: refining the in-plane translation parameters in each projection using 2-D sub-pixel matching and; and refining the in-plane rotation parameter in each projection using the 1-D search.
24. The article of manufacture of claim 23 , the method further comprising: determining whether the in-plane translation parameters and the in-plane rotation parameters in each projection have enough accuracy to achieve a desired registration accuracy; and repeating the method of claim 23 if the in-plane translation parameters and the in-plane rotation parameters do not have enough accuracy to achieve the desired registration accuracy; else refining the out-of-plane rotation parameters in each projection using the 1-D search.
25. The article of manufacture of claim 20 , wherein the in-plane transformation parameters comprise two in-plane translations and one in-plane rotation in each projection, wherein the second similarity measure comprises an optimized pattern intensity similarity measure, and wherein refining the in-plane transformation parameters and the out-of-plane rotation parameters comprises: refining the in-plane translation parameters in each projection using a steepest descent minimization; refining the in-plane rotation parameters in each projection using the steepest descent minimization; and refining the out-of-plane rotation parameters in each projection using the 1-D search.
26. The article of manufacture of claim 25 , the method further comprising: determining whether the in-plane translation parameters and the in-plane rotation parameters in each projection have enough accuracy to achieve a desired registration accuracy; and repeating the method of claim 25 if the in-plane translation parameters and the in-plane rotation parameters do not have enough accuracy to achieve the desired registration accuracy; else refining the out-of-plane rotation parameters in each projection using the 1-D search.
27. The article of manufacture of claim 18 , wherein the first similarity measure comprises a SSD similarity measure and the first search method comprises a hierarchical search.
28. The article of manufacture of claim 27 , wherein the hierarchical search comprises 3-parameter multi-level matching.
29. The article of manufacture of claim 27 , wherein the first similarity measure is one of a sum of squared differences (SSD) measure and a sum of absolute differences (SAD) measure.
30. The article of manufacture of claim 16 , the method further comprising converting the transformation parameters into a 3-D rigid transformation of the volume.
31. A system comprising a processing device, wherein the processing device is configured to estimate transformation parameters between a 2-D projection of a volume and a 2-D reference image of the volume in a plurality of search-phases, wherein to estimate the transformation parameters between the 2-D projection of the volume and the 2-D reference image of the volume, the processing device is configured to estimate in-plane transformation parameters between the 2-D projection of the volume and a 2-D reference image generated from 3-D scan data of the volume in a first search-phase and estimate out-of-plane rotation parameters between the 2-D projection and a plurality of 2-D reference images generated from the 3-D scan data of the volume in a second search-phase, and wherein the processing device is further configured to search for 2-D transformation parameters in each of the plurality of search-phases using combinations of search techniques and similarity measures in each search phase.
32. The system of claim 31 , wherein the processing device is further configured to repeat a search for one or more transformation parameters to achieve a desired registration accuracy between the 2-D projection of the volume and the 2-D reference image of the volume.
33. The system of claim 32 , wherein to estimate the transformation parameters between the 2-D projection of the volume and the 2-D reference image of the volume, the processing device is configured to estimate the in-plane transformation parameters between the 2-D projection of the volume and the 2-D reference image generated from the 3-D scan data of the volume, using a first similarity measure and a first search method in each of two or more projections, and wherein the processing device is further configured to estimate the out-of-plane rotation parameters between the 2-D projection and the plurality of 2-D reference images using a second similarity measure and a second search method in each of the two or more projections.
34. The system of claim 33 , further comprising a data storage device coupled with the data processing device to store a plurality of 2-D projections of the volume and a plurality of 2-D reference images generated from 3-D scan data of the volume.
35. The system of claim 34 , wherein the processing device is further configures to refine the in-plane transformation parameters and the out-of-plane rotation parameters using a second similarity measure and at least a third search method in each of the two or more projections.
36. The system of claim 35 , wherein the out-of-plane rotation parameters in each of the two or more projections comprise two out-of-plane rotation parameters, and wherein the second search method comprises a 1-D search in each of the two or more projections.
37. The system of claim 36 , wherein the 1-D search searches the two out-of-plane rotation parameters in each of the two or more projections.
38. The system of claim 36 , wherein one of the out-of-plane rotation parameters in each projection comprises one of the in-plane rotation parameters in another projection, and wherein the 1-D search searches only one of the two out-of-plane rotation parameters in each of the two or more projections.
39. The system of claim 36 , wherein the in-plane transformation parameters comprise two in-plane translations and one in-plane rotation in each projection, wherein the second similarity measure comprises an optimized pattern intensity similarity measure, and wherein to refine the in-plane transformation parameters in each projection, the processing device is further configured to refine the in-plane translation parameters in each projection using 2-D sub-pixel matching and to refine the in-plane rotation parameter in each projection using the 1-D search.
40. The system of claim 39 , wherein the processing device is further configured to determine whether the in-plane translation parameters and the in-plane rotation parameters in each projection have enough accuracy to achieve a desired registration accuracy, to further refine the in-plane transformation parameters in each projection if the in-plane translation parameters and the in-plane rotation parameters do not have enough accuracy to achieve the desired registration accuracy, else to refine the out-of-plane rotation parameters in each projection using the 1-D search.
41. The system of claim 36 , wherein the in-plane transformation parameters comprise two in-plane translations and one in-plane rotation in each projection, wherein the second similarity measure comprises an optimized pattern intensity similarity measure, and wherein to refine the in-plane transformation parameters and the out-of-plane rotation parameters the processing device is further configured to refine the in-plane translation parameters in each projection using a steepest descent minimization, to refine the in-plane rotation parameters in each projection using the steepest descent minimization, and to refine the out-of-plane rotation parameters in each projection using the 1-D search.
42. The system of claim 41 , wherein the processing device is further configured to determine whether the in-plane translation parameters and the in-plane rotation parameters in each projection have enough accuracy to achieve a desired registration accuracy, and to further to refine the in-plane transformation parameters and the out-of-plane rotation parameters if the in-plane translation parameters and the in-plane rotation parameters do not have enough accuracy to achieve the desired registration accuracy, else to refine the out-of-plane rotation parameters in each projection using the 1-D search.
43. The system of claim 34 , wherein the first similarity measure comprises a SSD similarity measure and the first search method comprises a hierarchical search.
44. The system of claim 43 , wherein the hierarchical search comprises 3-parameter multi-level matching.
45. The system of claim 43 , wherein the first similarity measure is one of a sum of squared differences (SSD) measure and a sum of absolute differences (SAD) measure.
46. The system of claim 34 , wherein the second similarity measure comprises an optimized pattern intensity similarity measure.
47. The system of claim 34 , further comprising: an imaging system coupled with the data storage device to generate the plurality of 2-D projection of the volume; and a treatment planning system to generate the plurality of 2-D reference images from the 3-D scan data of the volume, the plurality of 2-D reference images comprising a nominal in-plane reference image and a plurality of out-of-plane reference images in each of the two or more projections.
48. The system of claim 31 , wherein the processing device is further configured to convert the transformation parameters into a 3-D rigid transformation of the volume.
49. An apparatus, comprising:
means for estimating transformation parameters between a 2-D projection of a volume and a 2-D reference image of the volume in a plurality of search-phases, the estimating comprising:
estimating in-plane transformation parameters between the 2-D projection of the volume and a 2-D reference image generated from 3-D scan data of the volume in a first search-phase; and
estimating out-of-plane rotation parameters between the 2-D projection and a plurality of 2-D reference images generated from the 3-D scan data of the volume in a second search-phase; and
means for searching for 2-D transformation parameters in each of the plurality of search-phases using combinations of search techniques and similarity measures in each search phase.
50. The apparatus of claim 49 , further comprising means for repeating a search for one or more transformation parameters to achieve a desired registration accuracy between the 2-D projection of the volume and the 2-D reference image of the volume.
51. The apparatus of claim 50 , further comprising means for converting the transformation parameters into a 3-D rigid transformation of the volume.