Image-based flat panel alignment

• US 20070170373A1
• Filed: 01/26/2006
• Published: 07/26/2007
• Est. Priority Date: 01/26/2006
• Status: Active Grant

• Current Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Manthey, Dieter
• Granted Patent: US 7,511,286 B2
• Time in Patent Office: Days
• US Class Current: 250/491.100
• CPC Class Codes: A61B 6/587 Alignment of source unit to detector unit
• CPC Class Codes: A61N 2005/1054 using a portal imaging system
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam

Abstract

Some embodiments include determination of a first misalignment between an imaging device and an axis of a radiation beam emitted from a treatment head, determination of a rotational misalignment between the imaging device and the treatment head within a plane normal to the axis of the radiation beam, acquisition of an image using the imaging device, and modification of the acquired image based on the determined first misalignment and rotational misalignment. Embodiments may further include determination of a second rotational misalignment between the imaging device and the plane normal to the axis of the radiation beam, and modification of the acquired image based on the determined first misalignment, rotational misalignment and second rotational misalignment.

Claims

1. A method comprising:

determining a first misalignment between an imaging device and an axis of a radiation beam emitted from a treatment head;

determining a rotational misalignment between the imaging device and the radiation beam within a plane normal to the axis of the radiation beam;

acquiring an image using the imaging device; and

modifying the acquired image based on the determined first misalignment and rotational misalignment.

2. A method according to claim 1, wherein the image is acquired while the imaging device is at a first position and the treatment head is at a second position, the method further comprising:

moving the imaging device to a third position and the treatment head to a fourth position;

determining a second misalignment between the imaging device at the third position and a second axis of a second radiation beam emitted from the treatment head at the a fourth position;

determining a second rotational misalignment between the imaging device at the third position and the second radiation beam within a plane normal to the axis of the radiation beam;

acquiring a second image using the imaging device while the imaging device is at the third position and the treatment head is at the fourth position; and

modifying the acquired second image based on the determined second misalignment and second rotational misalignment.

3. A method according to claim 1, wherein determining the first misalignment comprises:

acquiring, using the imaging device, an image of a reticle mounted to the treatment head;

determining a center of the reticle in the image;

determining a center of the image; and

determining a vector between the center of the image and the center of the reticle in the image.

4. A method according to claim 3, wherein determining the rotational misalignment comprises:

determining a portion of the reticle in the image having a first orientation; and

determining an angle between the portion and a line associated with the first orientation.

5. A method according to claim 1, wherein determining the first misalignment comprises:

substantially closing a first pair of jaws of a collimator;

acquiring, using the imaging device, an image of a radiation beam having passed through the substantially closed first pair of jaws;

rotating the collimator;

acquiring, using the imaging device, an image of a second radiation beam having passed through the substantially closed first pair of jaws;

determining an intersection point between the image of the first radiation beam and the image of the second radiation beam;

determining a center of the image of the first radiation beam or of the image of the second radiation beam; and

determining a vector between the center and the intersection point.

6. A method according to claim 5, wherein determining the rotational misalignment comprises:

determining a portion of the image of the first radiation beam having a first orientation; and

determining an angle between the portion and a line associated with the first orientation.

7. A method according to claim 1, wherein determining the rotational misalignment comprises:

acquiring, using the imaging device, an image of a reticle mounted to the treatment head;

determining a portion of the reticle in the image having a first orientation; and

determining an angle between the portion and a line associated with the first orientation.

8. A method according to claim 1, wherein determining the rotational misalignment comprises:

substantially closing a first pair of jaws of a collimator;

acquiring, using the imaging device, an image of a radiation beam having passed through the substantially closed first pair of jaws;

determining a portion of the image of the first radiation beam having a first orientation; and

determining an angle between the portion and a line associated with the first orientation.

9. A method according to claim 1, further comprising:

determining a second rotational misalignment between the imaging device and the plane normal to the axis of the radiation beam,

wherein modifying the acquired image comprises modifying the acquired image based on the determined first misalignment, rotational misalignment and second rotational misalignment.

10. A method according to claim 9, wherein determining the second rotational misalignment comprises:

opening a first pair of jaws of a collimator;

acquiring, using the imaging device, an image of a radiation beam having passed through the first pair of jaws;

determining a width of the radiation beam in the acquired image; and

determining the second rotational misalignment based on the width and on a width of the radiation beam in the plane normal to the axis of the radiation beam.

11. A method according to claim 10, wherein opening the first pair of jaws of the collimator comprises:

opening a first jaw of the first pair of jaws,

the method further comprising;

rotating the collimator one hundred eighty degrees; and

acquiring, using the imaging device, a second image of a second radiation beam having passed through the first pair of jaws with the collimator rotated one hundred eighty degrees; and

determining a width of the second radiation beam in the second acquired image,

wherein determining the second rotational misalignment comprises determining the second rotational misalignment based on the width of the radiation beam, the width of the second radiation beam, and on the width of the radiation beam in the plane normal to the axis of the radiation beam.

12. An apparatus comprising:

a treatment head to emit a radiation beam;

an imaging device to acquire an image based on the radiation beam; and

a processing device to;

determine a first misalignment between the imaging device and an axis of the radiation beam;

determine a rotational misalignment between the imaging device and the treatment head within a plane normal to the axis of the radiation beam; and

modify the acquired image based on the determined first misalignment and rotational misalignment.

13. An apparatus according to claim 12, wherein the image is acquired while the imaging device is at a first position and the treatment head is at a second position, and wherein the processing device is to:

move the imaging device to a third position and the treatment head to a fourth position;

determine a second misalignment between the imaging device at the third position and a second axis of a second radiation beam emitted from the treatment head at the a fourth position;

determine a second rotational misalignment between the imaging device at the third position and the second radiation beam within a plane normal to the axis of the radiation beam;

acquire a second image using the imaging device while the imaging device is at the third position and the treatment head is at the fourth position; and

modify the acquired second image based on the determined second misalignment and second rotational misalignment.

14. An apparatus according to claim 12, wherein determination of the first misalignment comprises:

acquisition, using the imaging device, an image of a reticle mounted to the treatment head;

determination of a center of the reticle in the image;

determination of a center of the image; and

determination of a vector between the center of the image and the center of the reticle in the image.

15. An apparatus according to claim 14, wherein determination of the rotational misalignment comprises:

determination of a portion of the reticle in the image having a first orientation; and

determination of an angle between the portion and a line associated with the first orientation.

16. An apparatus according to claim 12, further comprising:

a collimator mounted to the treatment head, the collimator comprising at least a first pair of jaws,

wherein determination of the first misalignment comprises;

substantial closing of the first pair of jaws;

acquisition, using the imaging device, of an image of a radiation beam having passed through the substantially closed first pair of jaws;

rotation of the collimator;

acquisition, using the imaging device, of an image of a second radiation beam having passed through the substantially closed first pair of jaws;

determination of an intersection point between the image of the first radiation beam and the image of the second radiation beam;

determination of a center of the image of the first radiation beam or of the image of the second radiation beam; and

determination of a vector between the center and the intersection point.

17. An apparatus according to claim 16, wherein determination of the rotational misalignment comprises:

determination of a portion of the image of the first radiation beam having a first orientation; and

determination of an angle between the portion and a line associated with the first orientation.

18. An apparatus according to claim 12, wherein determination of the rotational misalignment comprises:

acquisition of, using the imaging device, an image of a reticle mounted to the treatment head;

determination of a portion of the reticle in the image having a first orientation; and

determination of an angle between the portion and a line associated with the first orientation.

19. An apparatus according to claim 12, further comprising:

a collimator mounted to the treatment head, the collimator comprising at least a first pair of jaws,

wherein determination of the rotational misalignment comprises;

substantial closing of the first pair of jaws;

acquisition, using the imaging device, of an image of a radiation beam having passed through the substantially closed first pair of jaws;

determination of a portion of the image of the first radiation beam having a first orientation; and

determination of an angle between the portion and a line associated with the first orientation.

20. An apparatus according to claim 12, wherein the processing device is to determine a second rotational misalignment between the imaging device and the plane normal to the axis of the radiation beam, and

wherein modification of the acquired image comprises modification of the acquired image based on the determined first misalignment, rotational misalignment and second rotational misalignment.

21. An apparatus according to claim 20, further comprising:

a collimator mounted to the treatment head, the collimator comprising at least a first pair of jaws,

wherein, to determine the second rotational misalignment, the processing device is to;

open the first pair of jaws;

acquire, using the imaging device, an image of a radiation beam having passed through the open first pair of jaws;

determine a width of the radiation beam in the acquired image; and

determine the second rotational misalignment based on the width and on a width of the radiation beam in the plane normal to the axis of the radiation beam.

22. An apparatus according to claim 21, wherein opening of the first pair of jaws comprises:

opening of a first jaw of the first pair of jaws; and

wherein the processing device is to;

rotate the collimator one hundred eighty degrees; and

acquire, using the imaging device, a second image of a second radiation beam having passed through the first pair of jaws with the collimator rotated one hundred eighty degrees;

determine a width of the second radiation beam in the second acquired image; and

determine the second rotational misalignment based on the width of the radiation beam, the width of the second radiation beam, and on a width of the radiation beam in the plane normal to the axis of the radiation beam.

23. A medium storing program code, the program code comprising:

code to determine a first misalignment between an imaging device and an axis of a radiation beam emitted from a treatment head;

code to determine a rotational misalignment between the imaging device and the treatment head within a plane normal to the axis of the radiation beam;

code to acquire an image using the imaging device; and

code to modify the acquired image based on the determined first misalignment and rotational misalignment.

24. A medium according to claim 23, wherein the code to acquire the image comprises code to acquire the image while the imaging device is at a first position and the treatment head is at a second position, and the program code further comprising:

code to move the imaging device to a third position and the treatment head to a fourth position;

code to determine a second misalignment between the imaging device at the third position and a second axis of a second radiation beam emitted from the treatment head at the a fourth position;

code to determine a second rotational misalignment between the imaging device at the third position and the second radiation beam within a plane normal to the axis of the radiation beam;

code to acquire a second image using the imaging device while the imaging device is at the third position and the treatment head is at the fourth position; and

code to modify the acquired second image based on the determined second misalignment and second rotational misalignment.

25. A medium according to claim 23, wherein the code to determine the first misalignment comprises:

code to acquire, using the imaging device, an image of a reticle mounted to the treatment head;

code to determine a center of the reticle in the image;

code to determine a center of the image; and

code to determine a vector between the center of the image and the center of the reticle in the image.

26. A medium according to claim 25, wherein the code to determine the rotational misalignment comprises:

code to determine a portion of the reticle in the image having a first orientation; and

code to determine an angle between the portion and a line associated with the first orientation.

27. A medium according to claim 23, wherein the code to determine the first misalignment comprises:

code to substantially close a first pair of jaws of a collimator;

code to acquire, using the imaging device, an image of a radiation beam having passed through the substantially closed first pair of jaws;

code to rotate the collimator;

code to acquire, using the imaging device, an image of a second radiation beam having passed through the substantially closed first pair of jaws;

code to determine an intersection point between the image of the first radiation beam and the image of the second radiation beam;

code to determine a center of the image of the first radiation beam or of the image of the second radiation beam; and

code to determine a vector between the center of the image and the intersection point.

28. A medium according to claim 23, the program code further comprising:

code to determine a second rotational misalignment between the imaging device and the plane normal to the axis of the radiation beam,

wherein the code to modify the acquired image comprises code to modify the acquired image based on the determined first misalignment, rotational misalignment and second rotational misalignment.

29. A medium according to claim 28, wherein the code to determine the second rotational misalignment comprises:

code to open a first pair of jaws of a collimator;

code to acquire, using the imaging device, an image of a radiation beam having passed through the first pair of jaws;

code to determine a width of the radiation beam in the acquired image; and

code to determine the second rotational misalignment based on the width and on a width of the radiation beam in the plane normal to the axis of the radiation beam.

30. A medium according to claim 29, wherein the code to open the first pair of jaws of the collimator comprises:

code to open a first jaw of the first pair of jaws,

the program code further comprising;

code to rotate the collimator one hundred eighty degrees; and

code to acquire, using the imaging device, a second image of a second radiation beam having passed through the first pair of jaws with the collimator rotated one hundred eighty degrees; and

code to determine a width of the second radiation beam in the second acquired image,

wherein the code to determine the second rotational misalignment comprises code to determine the second rotational misalignment based on the width of the radiation beam, the width of the second radiation beam, and on a width of the radiation beam field in the plane normal to the axis of the radiation beam.