DEVICE AND METHOD FOR POSITIONING A TARGET VOLUME IN A RADIATION THERAPY APPARATUS

• US 20090168960A1
• Filed: 12/12/2006
• Published: 07/02/2009
• Est. Priority Date: 12/12/2005
• Status: Active Grant

• Current Assignee: Ion Beam Applications s.a.
• Original Assignee: Ion Beam Applications s.a.
• Inventors: Jongen, Yves, Labarbe, Rudi
• Granted Patent: US 7,860,216 B2
• Time in Patent Office: Days
• US Class Current: 378/65
• CPC Class Codes: A61B 6/0421 with immobilising means
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: A61N 5/1065 Beam adjustment
• CPC Class Codes: A61N 5/1069 Target adjustment, e.g. moving the patient support

Abstract

Device for positioning a target volume (112) such, as a phantom or a patient in a radiation therapy apparatus, said apparatus directing a radiation beam (405) towards said target (112), characterized in that it comprises:—a target support (100) whereon the target is immobilized; a two dimensional radiation detector (103) fixed with fixations means (101,102, 104, 106 107; 301, 302, 304, 305, 306; 208, 209) in a known geometric relationship to said target support (100), said radiation detector (103) being capable of detecting the position of intersection of said radiation beam (105) with said detector (103); correcting means for correcting the relative position of said beam (105) and said target support 100), based on said detected intersection position.

Claims

1. A device for positioning a target in a patient in a radiation therapy apparatus, the apparatus directing a radiation beam towards the target the device comprising

a target support for immobilizing the target;

a two-dimensional radiation detector fixed with fixation device in a predetermined geometric relationship to the target support the radiation detector configured to detect an intersection position of the radiation beam with the detector; and

correcting device configured to correct a relative position of the beam and the target support, based on the detected intersection position.

2. The device according to claim 1, wherein the two-dimensional radiation detector comprises a first set of ionization chambers in a first orientation and a second set of ionization chambers in a second orientation.

3. The device according to claim 1, wherein the fixation device comprises fixation frames affixed to the target support, the detector located in close proximity to the target.

4. The device according to claim 1, wherein the fixation device comprises fixation frames affixed to the target support with a slidable carriage sliding on rails, the detector located in close proximity to the target.

5. The device according to claim 3, wherein said the fixation frames are circular arcs.

6. The device according to claim 1, wherein the detector and the radiation beam are arranged such that the radiation beam intersects with the detector in a substantially perpendicular direction.

7. The device according to claim 1, wherein the correcting device comprises an application device configured to apply a precise correction displacement to the radiation beam.

8. The device according to claim 1, wherein the correcting device comprises an application device configured to apply a precise correction displacement to the target support.

13. A radiation therapy apparatus having an eccentric gantry, the apparatus comprising the device of claim 1.

14. The device according to claim 1, wherein the target is selected from the group consisting of a phantom and a tumor.

15. The device according to claim 3, wherein the target support comprises indexed fixed holes for affixing the fixation frames.

16. The device according to claim 3, wherein the fixation frames are polygons.

9. A method for positioning a target in a patient in a radiation therapy apparatus, comprising:

determining a relative position between the target and a radiation detector;

providing a fixation device configured to fix the relative position during the subsequent steps;

determining an intended intersection point of the radiation beam with the detector;

directing a sub-therapeutic radiation beam towards the detector and determining an actual intersection point of the beam with the detector;

computing a correction vector which is a difference between locations of the intended and the actual intersection points; and

applying a correction to a relative position between the radiation beam and the radiation detector, whereby the actual intersection point coincides with the intended intersection point.

10. The method according to claim 9, wherein applying a correction comprises moving the radiation beam to correct the relative position between the radiation beam and the radiation detector.

11. The method according to claim 9, wherein applying a correction comprises moving the target and the detector to correct the relative position between the radiation beam and the radiation detector.

12. The method according to claim 9, wherein determining the relative position of the target and the detector comprises:

providing a detector having three or more points for fixation to a target support, the points having a geometric relationship with the detector;

installing the target in a fixed way on a target support;

providing markers on the target support at fixation points of the detector, the markers being visible in an imaging modality;

obtaining an image of the target using an imaging modality where both the target and the markers are visible;

determining from the image the geometric relationship of the target and the markers; and

inferring therefrom the geometric relationship between the target and the detector.

17. The method for positioning a target in a patient in a radiation therapy apparatus according to claim 9, wherein the apparatus comprises an eccentric gantry.

18. The method according to claim 9, wherein the target is selected from the group consisting of a phantom and a tumor.