System and method for in-layer synchronization for fast spot rescanning

Patent metadata

Field	Value
Publication number	US-10857392-B2
Application number	US-201715786392-A
Country	US
Kind code	B2
Filing date	Oct 17, 2017
Priority date	May 18, 2015
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

To overcome the difficulties inherent in conventional proton therapy systems, new techniques are described herein for synchronizing the application of proton radiation with the periodic movement of a target area. In an embodiment, a method is provided that combines multiple rescans of a spot scanning proton beam while monitoring the periodic motion of the target area, and aligning the applications of the proton beam with parameters of the periodic motion. For example, the direction(s) and frequency of the periodic motion may be monitored, and the timing, dose rate, and/or scanning direction and spot sequence of the beam can be adjusted to align with phases in the periodic motion.

First claim

What is claimed is:

1. A method for treatment of a target area with a radiation therapy beam, the method comprising:
monitoring a position of the target area; and
in response to detecting movements of the target area to different positions:
aligning the radiation therapy beam to the different positions of the target area, wherein the movements of the target area comprise a plurality of phases of periodic movement; and
administering a dosage to the different positions of the target area using the radiation therapy beam;

wherein said administering a dosage to the different positions of the target area comprises applying the radiation therapy beam as a number of multiple raster scans over the target area, and wherein said aligning comprises adjusting the number of the multiple raster scans to conform to the phases of periodic movement.

2. The method of claim 1 , wherein the radiation therapy beam comprises a spot scanning proton beam.

3. The method of claim 1 , wherein the phases of periodic movement are delineated by a plurality of transition periods between the plurality of phases of periodic movement.

4. The method of claim 1 , wherein said aligning further comprises an operation selected from the group consisting of:
adjusting a dose rate of an application of the radiation therapy beam based on a phase of periodic movement; and
gating applications of the radiation therapy beam outside of the phases of periodic movement, wherein the radiation therapy beam is not applied to the target area during transition periods between the phases of periodic movement.

5. The method of claim 1 , wherein said aligning further comprises inserting a pause between administering a dosage to a position of the target area and said administering a dosage to a different position of the target area to synchronize application of the radiation therapy beam with a frequency of the movements of the target area.

6. The method of claim 1 , wherein the movements of the target area comprise a movement of the target area selected from the group consisting of: a respiratory cycle; and a cardiac cycle.

7. The method of claim 1 , wherein said administering further comprises applying the radiation therapy beam in a short burst to the target area.

8. The method of claim 1 , wherein said aligning comprises an operation selected from the group consisting of: moving a nozzle through which the radiation therapy beam is emitted; moving a subject positioner on which a treatment subject containing the target area is positioned; and a combination of moving a nozzle through which the radiation therapy beam is emitted and moving a subject positioner on which a treatment subject containing the target area is positioned.

9. The method of claim 1 , wherein said monitoring comprises an operation selected from the group consisting of: continuous imaging of the target area; and tracking a motion surrogate that is correlated to movement of the target area.

10. The method of claim 1 , wherein said aligning comprises aligning a scanning direction of an application of the radiation therapy beam to conform to a direction of a movement exhibited by the target area during a phase of the periodic movement.

11. The method of claim 1 , wherein said aligning comprises aligning a starting position of an application of the radiation therapy beam to conform to a direction of a movement exhibited by the target area during a phase of the periodic movement.

12. A system, comprising:
a particle accelerator configured to produce a radiation therapy beam;
a gantry configured to receive the radiation therapy beam and to rotate around a target subject;
a nozzle configured to emit the radiation therapy beam at a target area in the target subject;
a sensor device configured to monitor a movement of the target area; and
a computing device configured to control motion and emission of the radiation therapy beam, wherein the computing device is operable for executing instructions stored in a readable medium, the instructions when executed performing a method comprising:
monitoring positions of the target area; and
in response to detecting movements of the target area to different positions:
aligning the radiation therapy beam to the different positions of the target area, wherein the movements of the target area comprise a plurality of phases of periodic movement, and wherein said aligning comprises aligning a scanning direction of an application of the radiation therapy beam to conform to a direction of a movement exhibited by the target area during a phase of the periodic movement; and
administering a dosage to the different positions of the target area using the radiation therapy beam;

wherein said administering a dosage to the different positions of the target area comprises applying the radiation therapy beam as a number of multiple raster scans over the target area, wherein said aligning also comprises adjusting the number of multiple raster scans to conform to the phases of periodic movement.

13. The system of claim 12 , wherein the radiation therapy beam comprises a spot scanning proton beam.

14. The system of claim 12 , wherein the plurality of phases of periodic movement are delineated by a plurality of transition periods between the plurality of phases of periodic movement.

15. The system of claim 12 , wherein said aligning further comprises an operation selected from the group consisting of:
adjusting a dose rate of an application of the radiation therapy beam based on a phase of periodic movement; and
gating applications of the radiation therapy beam outside of the phases of periodic movement, wherein the radiation therapy beam is not applied to the target area during transition periods between the phases of periodic movement.

16. The system of claim 12 , wherein said aligning further comprises inserting a pause between administering a dosage to a position of the target area and said administering a dosage to a different position of the target area to synchronize application of the radiation therapy beam with a frequency of the movements of the target area.

17. The system of claim 12 , wherein said administering further comprises applying the radiation therapy beam in a short burst to the target area.

18. The system of claim 12 , wherein said aligning comprises an operation selected from the group consisting of: moving the nozzle; moving the gantry; moving a subject positioner on which a treatment subject containing the target area is positioned; and a combination of moving the nozzle, moving the gantry, and moving a subject positioner on which a treatment subject containing the target area is positioned.

19. The system of claim 12 , wherein said monitoring comprises an operation selected from the group consisting of: continuous imaging of the target area; and tracking a motion surrogate that is correlated to movement of the target area.

20. The system of claim 12 , wherein said aligning also comprises aligning a starting position of an application of the radiation therapy beam to conform to a direction of a movement exhibited by the target area during a phase of the periodic movement.

Assignees

• Varian Medical Systems Particle Therapy Gmbh
• Varian Med Sys Inc

Inventors

• Bach Markus
• HUTH Isabel
• Heese Juergen
• PISKULICH Franko
• Dong Lei

Classifications

• A61N5/1049

  for verifying the position of the patient with respect to the radiation beam · CPC title

• A61N5/1044

  with multiple repetitions of the scanning pattern · CPC title

• A61N5/1037

  taking into account the movement of the target, e.g. 4D-image based planning · CPC title

• A61N5/1081 Primary

  Rotating beam systems with a specific mechanical construction, e.g. gantries · CPC title

• A61N5/1068

  Gating the beam as a function of a physiological signal · CPC title