Use of a single X-ray image for quality assurance of tracking
A method and system for aligning a volume of interest in a three-dimensional treatment coordinate system with a reference position using stereoscopic imaging data and for monitoring and correcting alignment of the volume of interest in the three-dimensional treatment coordinate system using monoscopic imaging data.
1. A method, comprising:
aligning a volume of interest (VOI) in a three-dimensional (3D) treatment coordinate system with a reference position using imaging data;
monitoring alignment of the VOI in the 3D treatment coordinate system during a radiation treatment using monoscopic imaging data generated by a single imaging source;
detecting displacement of the VOI in the 3D treatment coordinate system using the monoscopic imaging data;
determining whether the displacement exceeds a displacement threshold; and
automatically modifying the radiation treatment if the displacement exceeds the displacement threshold.
2. The method of claim 1 , further comprising:
acquiring stereoscopic imaging data if the displacement exceeds the displacement threshold; and
realigning the VOI in the 3D treatment coordinate system using the stereoscopic imaging data.
3. The method of claim 1 , further comprising determining that the VOI can be realigned in the 3D treatment coordinate system using the monoscopic imaging data if the displacement does not exceed the displacement threshold.
4. The method of claim 3 , further comprising realigning the VOI in the 3D treatment coordinate system using the monoscopic imaging data.
5. The method of claim 4 , wherein the imaging data comprises two-dimensional (2D) projection images, and wherein aligning the VOI with the reference position comprises:
acquiring first two-dimensional (2D) projection images of the VOI in each of two or more projections;and
registering the first 2D projection images of the VOI in each of the two or more projections with 2D reference images of the VOI in each of the two or more projections, wherein the 2D reference images of the VOI are derived from 3D transformations of 3D scan data of the VOI.
6. The method of claim 5 , wherein the registering comprises:
comparing the first 2D projection images in each of the two or more projections with the 2D reference images in each of the two or more projections;
determining a first similarity measure between the first 2D projection image in each of the two or more projections and selected 2D reference images in each of the two or more projections;and
finding a first 3D transformation between a coordinate system of the VOI and a coordinate system of the 3D scan data of the VOI that maximizes the first similarity measure, wherein the first 3D transformation maps voxels in the coordinate system of the VOI to corresponding voxels in the coordinate system of the 3D scan data of the VOI.
7. The method of claim 6 , wherein aligning the VOI with the reference position comprises at least one of moving the VOI through an inverse of the first 3D transformation and positioning a treatment source to compensate for the first 3D transformation.
8. The method of claim 6 , wherein monitoring the alignment of the VOI in the 3D treatment coordinate system comprises:
acquiring a second 2D projection image of the VOI in one of the two or more projections;and
comparing the second 2D projection image with a selected 2D reference image of the VOI in the one of the two or more projections.
9. The method of claim 8 , wherein detecting the movement of the VOI comprises:
determining a second similarity measure between the second 2D projection image of the VOI and the selected 2D reference image of the VOI in the one of the two or more projections;and
comparing the second similarity measure to the first similarity measure.
10. The method of claim 9 , wherein detecting the movement of the VOI further comprises finding a second 3D transformation of the 3D scan data that maximizes the second similarity measure.
11. The method of claim 10 , wherein realigning the VOI in the 3D treatment coordinate system comprises moving the VOI through an inverse of the second 3D transformation.
12. The method of claim 10 , wherein realigning the VOI in the 3D treatment coordinate system comprises positioning a treatment source to compensate for the second 3D transformation.
13. The method of claim 10 , wherein a difference between the second similarity measure and the first similarity measure is less than a critical value, the method further comprising continuing a radiation treatment procedure based on the 3D transformation between the coordinate system of the VOI and the coordinate system of the 3D scan data of the VOI.
14. The method of claim 10 , wherein a difference between the second similarity measure and the first similarity measure is greater than or equal to a critical value, the method further comprising interrupting a radiation treatment procedure until the imaging data is available.
15. The method of claim 6 , wherein monitoring the alignment of the VOI in the 3D treatment coordinate system comprises:
acquiring a second 2D projection image of the VOI in one of the two or more projections; and
comparing the second 2D projection image with a first 2D projection image of the VOI in the one of the two or more projections.
16. A treatment delivery system, comprising:
a positioning system to position a volume of interest (VOI);
an imaging system configured to acquire images of the VOI;and
a processing device to control the imaging system and the positioning system, wherein the processing device is configured to:
align the VOI with a reference position in a three-dimensional (3D) treatment coordinate system using the images;
monitor alignment of the VOI in the 3D treatment coordinate system during a radiation treatment using monoscopic imaging data generated by a single imaging source;
detect displacement of the VOI in the 3D treatment coordinate system using the monoscopic imaging data;
determine whether the displacement exceeds a displacement threshold;and
automatically modify the radiation treatment if the displacement exceeds the displacement threshold.
17. The treatment delivery system of claim 16 , wherein the processing device is further configured to detect movement of the VOI in the 3D treatment coordinate system using the monoscopic imaging data.
18. The treatment delivery system of claim 17 , wherein the processing device is further configured to determine if the VOI can be realigned in the 3D treatment coordinate system using the monoscopic imaging data.
19. The treatment delivery system of claim 17 , wherein the processing device is further configured to use the monoscopic imaging data to control the positioning system to realign the VOI in the 3D treatment coordinate system.
20. The treatment delivery system of claim 17 , where the positioning system comprises a robotic positioning system having five or more degrees of freedom.
21. The treatment delivery system of claim 17 , further comprising a radiation treatment source controlled by the processing device, wherein the processing device is configured to use the monoscopic imaging data to position the radiation treatment source to compensate for the displacement of the VOI.
22. An article of manufacture, comprising a non-transitory computer-readable medium including instructions that, when executed by a computer, cause the computer to perform operations comprising:
aligning a volume of interest (VOI) in a three-dimensional (3D) treatment coordinate system with a reference position using imaging data;
monitoring alignment of the VOI in the 3D treatment coordinate system during a radiation treatment using monoscopic imaging data generated by a single imaging source;
detecting displacement of the VOI in the 3D treatment coordinate system using the monoscopic imaging data;
determining whether the displacement exceeds a displacement threshold;and
automatically modifying the radiation treatment if the displacement exceeds the displacement threshold.
23. The article of manufacture of claim 22 , wherein aligning the VOI with the reference position comprises:
acquiring first two-dimensional (2D) projection images of the VOI in each of two or more projections;and
registering the first 2D projection images of the VOI in each of the two or more projections with 2D reference images of the VOI in each of the two or more projections, wherein the 2D reference images of the VOI are derived from 3D transformations of 3D scan data of the VOI, wherein registering comprises:
comparing the first 2D projection image in each of the two or more projections with the 2D reference images in each of the two or more projections;
determining a first similarity measure between the first 2D projection image in each of the two or more projections and selected 2D reference images in each of the two or more projections;and
finding a first 3D transformation between a coordinate system of the VOI and a coordinate system of the 3D scan data of the VOI that maximizes the first similarity measure, wherein the first 3D transformation maps voxels in the coordinate system of the VOI to corresponding voxels in the coordinate system of the 3D scan data of the VOI.
24. The article of manufacture of claim 23 , wherein aligning the VOI with the reference position comprises moving the VOI through an inverse of the first 3D transformation or positioning a treatment source to compensate for the first 3D transformation.
25. The article of manufacture of claim 23 , wherein monitoring the alignment of the VOI in the 3D treatment coordinate system comprises:
acquiring a second 2D projection image of the VOI in one of the two or more projections; and
comparing the second 2D projection image with a selected 2D reference image of the VOI in the one of the two or more projections.
26. The article of manufacture of claim 25 , wherein detecting the movement of the VOI comprises:
determining a second similarity measure between the second 2D projection image of the VOI and the selected 2D reference image of the VOI in the one of the two or more projections; and
comparing the second similarity measure to the first similarity measure.
27. The article of manufacture of claim 25 , wherein detecting the movement of the VOI further comprises finding a second 3D transformation of the 3D scan data that maximizes the second similarity measure.
28. The article of manufacture of claim 27 , further comprising:
realigning the VOI in the 3D treatment coordinate system using the monoscopic imaging data, wherein realigning the VOI in the 3D treatment coordinate system comprises either moving the VOI through an inverse of the second 3D transformation, or positioning a treatment source to compensate for the second 3D transformation.
29. An apparatus, comprising:
means for aligning a volume of interest in a 3D coordinate system with a reference position using imaging data; and
means for monitoring alignment of the volume of interest during a radiation treatment using monoscopic imaging data generated by a single imaging source;
means for detecting displacement of the VOI in the 3D treatment coordinate system using the monoscopic imaging data;
means for determining whether the displacement exceeds a displacement threshold; and
means for automatically modifying the radiation treatment if the displacement exceeds the displacement threshold.
30. The apparatus of claim 29 , further comprising means for realigning the VOI in the 3D treatment coordinate system using the monoscopic imaging data.