Programmable particle scatterer for radiation therapy beam formation
Interposing a programmable path length of one or more materials into a particle beam modulates scattering angle and beam range in a predetermined manner to create a predetermined spread out Bragg peak at a predetermined range. Materials can be “low Z” and “high Z” materials that include fluids. A charged particle beam scatterer/range modulator can comprise a fluid reservoir having opposing walls in a particle beam path and a drive to adjust the distance between the walls of the fluid reservoir under control by a programmable controller. A “high Z” and, independently, a “low Z” reservoir, arranged in series, can be used. When used for radiation treatment, the beam can be monitored by measuring beam intensity, and the programmable controller can adjust the distance between the opposing walls of the “high Z” reservoir and, independently, the distance between the opposing walls of the “low Z” reservoir according to a predetermined relationship to integral beam intensity. Beam scattering and modulation can be done continuously and dynamically during a treatment in order to deposit dose in a target volume in a predetermined three dimensional distribution.
1. A charged particle beam scatterer/range modulator comprising:
first and second fluid reservoirs, the first and second reservoirs each having opposing walls in a particle beam path;
a drive to adjust the distance between the walls of at least one of the first and second fluid reservoirs through a range of values; and
a programmable controller for the drive to adjust the distance between the walls of at least one of the first and second reservoirs during exposure of a target to the beam.
2. The scatterer/modulator of claim 1 wherein the distance between the opposing walls of at least one of the first and second reservoirs is continuously adjustable.
3. The scatterer/modulator of claim 2 wherein the first and second fluid reservoirs are arranged in series in the particle beam path.
4. The scatterer/modulator of claim 3 wherein the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir are continuously adjustable.
5. The scatterer/modulator of claim 4 further including a high Z material within the first reservoir and a low Z material within the second reservoir.
6. The scatterer/modulator of claim 1 wherein the charged particles are protons.
7. A radiation treatment apparatus, comprising:
a source of charged particles that provides a charged particle beam; and
a charged particle beam scatterer/range modulator that includes
first and second fluid reservoirs each having opposing walls in a particle beam path;
a drive to adjust the distance between the walls of at least one of the first and second reservoirs through a range of values; and
a programmable controller for the drive to adjust the distance between the walls of at least one of the first and second reservoirs during exposure of a target to the beam.
8. The apparatus of claim 7 wherein the distance between the opposing walls of at least one of the first and second reservoirs is continuously adjustable.
9. The apparatus of claim 8 wherein the first and a second reservoirs arranged in series in the particle beam path.
10. The apparatus of claim 9 wherein the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir are continuously adjustable.
11. The apparatus of claim 10 further including a high Z material within the first reservoir and a low Z material within the second reservoir.
12. The apparatus of claim 11 wherein the charged particles are protons.
13. The apparatus of claim 12 wherein the source is a cyclotron.
14. The apparatus of claim 13 wherein the cyclotron is a synchrocyclotron.
15. The apparatus of claim 10 further including
a beam monitor for measuring particle beam intensity, the programmable controller adjusting the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir according to beam intensity.
16. The apparatus of claim 15 wherein the programmable controller adjusts distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir continuously and dynamically.
17. A method of treating a patient by directing a charged particle beam at a target within said patient, comprising:
producing a charged particle beam;
directing the charged particle beam through first and second fluid reservoirs each having opposing walls in a particle beam path;
adjusting the distance between opposing walls of at least one of the first and second fluid reservoirs through a range of values during exposure of a target to the beam under control of a programmable controller.
18. The method of claim 17 wherein the charged particle beam is directed through the first and second reservoirs in series in the particle beam path.
19. The method of claim 18 further including continuously adjusting the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir.
20. The method of claim 19 further including measuring beam intensity; and communicating beam intensity to the programmable controller, wherein the programmable controller adjusts the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir according to beam intensity.
21. The method of claim 20 wherein the first reservoir contains a high Z material within and the second reservoir contains a low Z material.
22. The method of claim 17 wherein the charged particles are protons.
23. The method of claim 17 wherein the charged particle beam is produced by a cyclotron.
24. The method of claim 23 wherein the cyclotron is a synchrocyclotron.
25. A radiation treatment apparatus, comprising:
a synchrocyclotron that provides a charged particle beam; and
a charged particle beam scatterer/range modulator that includes
first and second fluid reservoirs disposed in an extraction channel of the synchrocyclotron and having opposing walls in a particle beam path;
a drive to adjust the distance between the walls of at least one of the first and second reservoirs through a range of values; and
a programmable controller for the drive to adjust the distance between the walls of at least one of the first and second reservoirs during exposure of a target to the beam.
26. Apparatus of claim 25 wherein the distance between the opposing walls of at least one of the first and second reservoirs is continuously adjustable.
27. The apparatus of claim 26 wherein the first and second reservoirs are arranged in series in the particle beam path.
28. The apparatus of claim 27 wherein the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir are continuously adjustable.
29. The apparatus of claim 28 further including a high Z material within the first reservoir and a low Z material within the second reservoir.
30. The apparatus of claim 28 wherein the charged particles are protons.
31. The apparatus of claim 28 further including a beam monitor for measuring particle beam intensity, the programmable controller adjusting the distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir according to beam intensity.
32. The apparatus of claim 31 wherein the programmable controller adjusts distance between the opposing walls of the first reservoir and, independently, the distance between the opposing walls of the second reservoir continuously and dynamically.