Increased beam output and dynamic field shaping for radiotherapy system

Patent metadata

Field	Value
Publication number	US-11007381-B2
Application number	US-201816193794-A
Country	US
Kind code	B2
Filing date	Nov 16, 2018
Priority date	Nov 16, 2017
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

Systems and methods provide radiotherapy treatment by focusing an electron beam on an x-ray target (e.g., a tungsten plate) to produce a high-yield x-ray output with improved field shaping. A modified electron beam spatial distribution is employed to scan the x-ray target, such as a 2D periodic beam path, which advantageously lowers the x-ray target temperature compared to the typical compact beam spatial distribution. As a result, the x-ray target can produce a high yield output without sacrificing the x-ray target life span. The use of a 2D periodic beam path allows a much colder x-ray target functioning regime such that more dosage can be applied in a short period of time compared to existing techniques.

First claim

What is claimed is:

1. A radiotherapy treatment system comprising:
a computer system;
an electron emission device for producing and emitting an electron beam;
a target;
a plurality of steering coils for providing magnetic fields in perpendicular directions for steering said electron beam to said target, wherein said target generates x-rays responsive to an interaction with said electron beam; and
a field shaping device configured to be placed between said target and a patient, said field shaping device operable to shape a treatment volume of said x-rays,
wherein said computer system comprises instructions, that when executed, cause said computer system to control said plurality of steering coils to scan said electron beam across said target in a 2D periodic path to produce a 2D periodic distribution of x-rays.

2. The radiotherapy treatment system as described in claim 1 , wherein said electron emission device comprises:
an electron gun assembly; and
a linear accelerator coupled to receive electrons from said electron gun assembly, and operable to produce said electron beam emitted from said electron emission device.

3. The radiotherapy treatment system as described in claim 1 , wherein said 2D periodic path comprises a Lissajous type shape.

4. The radiotherapy treatment system as described in claim 1 , wherein said 2D periodic path comprises spherical harmonic based shapes.

5. The radiotherapy treatment system as described in claim 1 , wherein said 2D periodic path comprises a linear combination of an s-wave shape, a p-wave shape, and a d-wave shape.

6. The radiotherapy treatment system as described in claim 5 , wherein said 2D periodic path comprises a non-Cartesian shape for shaping the electron beam.

7. The radiotherapy treatment system as described in claim 1 , wherein said instructions, when executed, cause said computer system to adjust at least one of a voltage and a current over said plurality of steering coils.

8. A radiotherapy treatment system comprising:
an electron emission device for producing and emitting an electron beam;
a target;
a plurality of steering coils for providing magnetic fields in perpendicular directions for steering said electron beam to said target, wherein said target generates x-rays responsive to an interaction with said electron beam;
a control device coupled to said plurality of steering coils; and
a field shaping device comprising a multileaf collimator, said field shaping device configured to be placed between said target and a patient, said field shaping device operable to shape a treatment volume of said x-rays, and
wherein said control device is operable to control said plurality of steering coils to cause said electron beam to scan across said target in a 2D periodic path to produce a 2D periodic distribution of x-rays, and wherein further a shape of said 2D periodic path in a combination with a physical configuration and an orientation of said field shaping device define a resultant treatment volume of x-rays exposed to said patient.

9. The radiotherapy treatment system as described in claim 8 , wherein said electron emission device comprises:
an electron gun assembly; and
a linear accelerator coupled to receive electrons from said electron gun assembly, and operable to produce said electron beam, wherein said electron beam is of a range from 1 MeV to 300 MeV.

10. The radiotherapy treatment system as described in claim 9 , wherein said 2D periodic path comprises a Lissajous type path.

11. The radiotherapy treatment system as described in claim 9 , wherein said 2D periodic path comprises spherical harmonic based shapes.

12. The radiotherapy treatment system as described in claim 11 , wherein said 2D periodic path comprises a linear combination of an s-wave shape, a p-wave shape, and a d-wave shape.

13. The radiotherapy treatment system as described in claim 8 , wherein said control device is operable to control said magnetic fields of said plurality of steering coils by adjusting at least one of a voltage and a current over said plurality of steering coils.

14. A method of generating an x-ray treatment volume using a radiotherapy treatment system, said method comprising:
generating and emitting an electron beam using an electron emission device;
steering said electron beam onto a target and dynamically scanning said electron beam across said target in a 2D periodic path;
producing, via said target, and responsive to an interaction with said electron beam being scanned thereon in accordance with said 2D periodic path, a distribution of x-rays; and
producing a resultant treatment volume of said distribution or x-rays by shaping said distribution of x-rays using a field shaping device, wherein a shape of said 2D periodic path in a combination with a physical configuration and an orientation of said field shaping device define said resultant treatment volume of x-rays.

15. The method as described in claim 14 , wherein said electron emission device comprises:
an electron gun assembly; and
a linear accelerator coupled to receive electrons from said electron gun assembly, and operable to produce said electron beam emitted from said electron emission device.

16. The method as described in claim 14 , wherein said 2D periodic path comprises a Lissajous type path.

17. The method as described in claim 14 , wherein said 2D periodic path comprises spherical harmonic based shapes.

18. The method as described in claim 17 , wherein said 2D periodic path comprises a linear combination of an s-wave shape, a p-wave shape, and a d-wave shape.

19. The method as described in claim 14 , further comprising adjusting at least one of a voltage and a current over a plurality of steering coils to scan said electron beam across said target in said 2D periodic path.

20. The method as described in claim 14 , wherein said 2D periodic path comprises a convex hull.

Assignees

• Varian Med Sys Inc

Inventors

• Purwar Anuj
• Constantin Dragos
• Clayton James

Classifications

• A61N2005/1092

  Details · CPC title

• A61N5/1082

  having multiple beam rotation axes · CPC title

• A61N5/1081

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

• A61N5/1078

  Fixed beam systems · CPC title

• A61N5/1067

  in real time, i.e. during treatment · CPC title