RF accelerator method and apparatus used in conjunction with a charged particle cancer therapy system

• US 8,373,146 B2
• Filed: 11/16/2009
• Issued: 02/12/2013
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Andrey Vladimirovich Balakin, Pavel Vladimirovich Balakin
• Original Assignee: Vladimir Balakin
• Inventors: Balakin, Vladimir
• Primary Examiner(s): MASKELL, MICHAEL P
• Application Number:
  US12/619,278
• Publication Number:
  US 20100060209A1
• Time in Patent Office: 1,184 Days
• Field of Search: 250/492.1, 250/492.2, 250/492.3, 250/493.1, 250/396.R, 315500-503, 315/506, 315/507
• US Class Current: 250/492.3
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 7/10 Arrangements for ejecting particles from orbits

Abstract

The invention comprises a radio-frequency accelerator method and apparatus used in conjunction with multi-axis charged particle radiation therapy of cancerous tumors. An RF synthesizer provides a low voltage RF signal, that is synchronized to the period of circulation of protons in the proton beam path, to a set of integrated microcircuits, loops, and coils where the coils circumferentially enclose the proton beam path in a synchrotron. The integrated components combine to provide an accelerating voltage to the protons in the proton beam path in a size compressed and price reduced format. The integrated RF-amplifier microcircuit/accelerating coil system is operable from about 1 MHz, for a low energy proton beam, to about 15 MHz, for a high energy proton beam.

Claims

1. An apparatus for accelerating a charged particle, comprising:

a synchrotron, said synchrotron comprising;

a center;

a charged particle circulation beam path running;

about said center;

through straight sections; and

through turning sections, wherein each of said turning sections comprises a plurality of bending magnets, each of said bending magnets comprising;

a gap, said charged particle beam path running through said gap, and

a core, wherein said core terminates at said gap with a surface comprising a finish of less than about ten microns polish;

a winding coil winding about said core;

a correction coil winding about said core, wherein said correction coil operates at less than three percent of a power of said winding coil;

an accelerator system, said accelerator system comprising;

a set of at least five coils, each of said coils circumferentially surrounding a section of said charged particle circulation beam path;

a set of at least five wire loops;

a set of at least five microcircuits, each of said microcircuits integrated to one of said loops, wherein each of said loops completes at least one turn about at least one of said coils; and

a radio-frequency synthesizer configured to send a low voltage signal to each of said microcircuits, each of said microcircuits amplifying said low voltage signal yielding an acceleration voltage.

2. The apparatus of claim 1, wherein said low voltage signal further comprises synchronization with a period of circulation of the charged particle in said charged particle circulation beam path.

3. The apparatus of claim 1, wherein said coils comprise a ferrite material, wherein each of said microcircuits integrated to said loops comprises an integration circuit.

4. The apparatus of claim 1, said radio-frequency amplifier configured to operate with impedance and/or resistance operable at frequencies above about ten megahertz.

5. The apparatus of claim 1, wherein at least one of said bending magnets further comprises:

a first focusing edge; and

a second focusing edge,

wherein said at least one of said bending magnets terminates on opposite sides with said first focusing edge and said second focusing edge,

wherein a first plane established by said first focusing edge intersects a plane established by said second focusing edge beyond said center of said synchrotron,

wherein each of said first focusing edge and said second focusing edge bend the charged particle toward said center of said synchrotron.

6. The apparatus of claim 1, wherein at least two of said plurality of bending magnets further comprise a magnetic field focusing section, said focusing section comprising:

a geometry tapering from a first cross-sectional area to a second cross-sectional area, said second cross-sectional area comprising less than two-thirds of an area of said first cross-sectional area, said first cross-sectional area parallel said second cross-sectional area, said second cross-sectional area proximate said charged particle beam path, wherein during use a magnetic field concentrates in density from said first cross-sectional area to said second-cross-sectional area.

7. The apparatus of claim 1, wherein at least one of said turning sections comprises at least four bending magnets, said four bending magnets comprising at least eight edge focusing surfaces, wherein geometry of said edge focusing surfaces focuses the charged particles in said charged particle circulation beam path during use.

8. The apparatus of claim 1, wherein each of said turning sections turns the charged particles by about ninety degrees.

9. The apparatus of claim 1, wherein at least one of said bending magnets comprises a tapered core, said tapered core comprising a first cross-section distance at least one and a half times longer than a second cross-section distance, said second cross-section distance proximate a gap, said gap having a surface polish of less than about ten microns roughness, said charged particle circulation beam path running through said gap.

10. The apparatus of claim 1, wherein a number of said turning sections comprises exactly four turning sections, wherein each of said four turning sections turns the charged particle circulation beam path about ninety degrees, said synchrotron capable of accelerating the charged particles to at least 300 MeV.

11. The apparatus of claim 10, wherein said four turning sections comprise at least thirty-two charged particle edge focusing surfaces.

12. The apparatus of claim 1, wherein said turning sections comprise at least eight bending magnets, wherein said charged particle circulation beam path does not pass through any operational quadrupole magnets.

13. The apparatus of claim 1, further comprising:

an extraction control algorithm, said extraction control algorithm receiving input generated by a current originating at an extraction foil, said extraction foil proximate said charged particle circulation beam path, said extraction control algorithm comparing a feedback input to an irradiation plan, said extraction control algorithm adjusting a radio-frequency field in a radio-frequency cavity system.

14. The apparatus of claim 1, further comprising:

a winding coil, wherein a winding turn in said winding coil wraps around at least two of said bending magnets, wherein said winding turn does not occupy space directly between said at least two of said bending magnets.

15. The apparatus of claim 1, wherein said circulation beam path comprises a length of less than about sixty meters, wherein a number of said straight sections equals a number of said turning sections.

16. The apparatus of claim 1, further comprising:

an extraction foil, said extraction foil proximate said charged particle beam path in said synchrotron, wherein during extraction the charged particles strike said extraction foil generating a current, said current used in controlling said intensity.

17. The apparatus of claim 16, wherein a first level of said intensity is used when energy levels of the charged particles reach a distal region of the tumor during each of said at least five irradiation positions, wherein a second level of said intensity is used when energy levels of the charged particles reach an ingress region of the tumor during said each of said at least five irradiation positions, wherein said first intensity is greater than said second intensity.

18. A method for accelerating charged particles, comprising:

accelerating charged particles with a synchrotron, said synchrotron comprising;

a center;

a charged particle circulation beam path running;

about said center;

through straight sections; and

through turning sections, wherein each of said turning sections comprises a plurality of bending magnets;

an accelerator system, said accelerator system comprising;

a set of at least five coils, each of said coils circumferentially surrounding a section of said charged particle circulation beam path;

a set of at least five wire loops;

a set of at least five microcircuits, each of said microcircuits integrated to one of said loops, wherein each of said loops completes at least one turn about at least one of said coils;

applying an acceleration voltage to the charged particles, said acceleration voltage controlled with a radio-frequency synthesizer sending a low voltage signal to each of said microcircuits, each of said microcircuits amplifying said low voltage signal yielding said acceleration voltage;

increasing intensity of the charged particles when charged particle delivery efficiency increases; and

decreasing said intensity of the charged particles when said charged particle delivery efficiency decreases, wherein said charged particle delivery efficiency comprises a measure of relative energy delivered to the tumor versus surrounding healthy tissue.

19. The method of claim 18, further comprising the steps of:

controlling a magnetic field in at least one of said bending magnets, said at least one of said bending magnets comprising;

a tapered iron based core adjacent a gap, said core comprising a surface polish of less than about ten microns roughness; and

a focusing geometry comprising;

a first cross-sectional distance of said iron based core forming an edge of said gap,

a second cross-sectional distance of said iron based core not in contact with said gap, wherein said second cross-sectional distance is at least fifty percent larger than said first cross-sectional distance, said first cross-sectional distance running parallel said second cross-sectional distance.

20. The method of claim 18, further comprising the steps of:

controlling energy of the charged particles during an extraction phase of the charged particles from said synchrotron; and

controlling intensity of the charged particles during said extraction phase of the charged particles from said synchrotron.

21. A method for controlling energy of charged particles deliverable to a tumor of a patient, comprising the steps of:

controlling energy of the charged particles in a synchrotron, said synchrotron comprising an accelerator system, said accelerator system comprising;

a set of at least ten coils;

a set of at least ten wire loops; and

a set of at least ten microcircuits, each of said microcircuits integrated to one of said loops, wherein each of said loops completes at least one turn about at least one of said coils;

using a radio-frequency synthesizer, sending a low voltage signal to each of said microcircuits, each of said microcircuits amplifying said low voltage signal yielding an acceleration voltage applied to the charged particles; and

increasing intensity of the charged particles when targeting a distal portion of the tumor, wherein said distal portion of said tumor changes with rotation of the patient on a platform rotating to as least ten distinct rotational positions in a period of less than one minute during irradiation of the tumor by the charged particles.

22. The method of claim 21, further comprising the steps of:

varying intensity of the charged particles dependent upon efficiency of delivery of energy of the charged particles within the tumor versus delivery of energy of the charged particles to healthy tissue of the patient.

23. The method of claim 21, further comprising the step of:

dynamically timing delivery of the charged particles at a set point in at least three sequential respiration cycles, wherein each of three sequential respiration cycles comprise a separate length of time.

24. The method of claim 21, further comprising the step of:

terminating the charged particle beam path in a distal region of the tumor for each of at least five irradiation positions, wherein the distal region comprises a furthest point of entry of the charged particles into the patient.