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

• US 8,198,607 B2
• Filed: 11/09/2009
• Issued: 06/12/2012
• 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:
  US12/614,733
• Publication Number:
  US 20100059686A1
• Time in Patent Office: 946 Days
• Field of Search: 250/396.R, 250/492.1, 250/492.3, 313/62, 315/503, 315/504
• US Class Current: 250/492.1
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: H01J 3/04 Ion guns
• CPC Class Codes: H01J 3/14 Arrangements for focusing or reflecting ray or beam H01J3/02, H01J3/04 take precedence
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 5/06 Multistage accelerators
• CPC Class Codes: H05H 7/10 Arrangements for ejecting particles from orbits

Abstract

The invention comprises a tandem accelerator method and apparatus, which is part of an ion beam injection system used in conjunction with multi-axis charged particle radiation therapy of cancerous tumors. The negative ion beam source includes an injection system vacuum system and a synchrotron vacuum system separated by a foil, where negative ions are converted to positive ions. The foil is sealed to the edges of the vacuum tube providing for a higher partial pressure in the injection system vacuum chamber and a lower pressure in the synchrotron vacuum system. Having the foil physically separating the vacuum chamber into two pressure regions allows for fewer and/or smaller pumps to maintain the lower pressure system in the synchrotron as the inlet hydrogen gas is extracted in a separate contained and isolated space by the injection partial vacuum system.

Claims

1. An apparatus for injecting a charged particle beam into an accelerator of an irradiation device, said irradiation device irradiating a tumor during use, said apparatus comprising:

a negative ion source, said negative ion source configured to produce negative ions in a negative ion beam; and

a converting foil, said converting foil configured to convert the negative ion beam into the charged particle beam, wherein said converting foil provides a pressure seal between an ion beam formation side of said irradiation device and a synchrotron side of said irradiation device, wherein a first pump system operates to maintain a first vacuum in said ion beam formation side of said converting foil, wherein a second pump system operates to maintain a second vacuum in said synchrotron side of said irradiation device.

2. The apparatus of claim 1, wherein said converting foil configured to convert the negative ions into a proton beam, wherein said converting foil provides a vacuum barrier between the negative ions and the charged particle beam, wherein the charged particle beam comprises a proton beam.

3. The apparatus of claim 1, wherein said converting foil comprises:

a beryllium carbon film, wherein said carbon film comprises a thickness of about thirty to two hundred micrometers, wherein said carbon film forms a vacuum barrier between said negative ion source and said synchrotron.

4. The apparatus of claim 1, further comprising:

an ion beam focusing lens, said lens configured to during use comprise field lines running, in a vacuum system, through the negative ion beam, wherein the field lines focus the negative ion beam,

said ion beam focusing lens further comprising;

a first focusing electrode circumferentially surrounding the negative ion beam;

a second focusing electrode comprising metal conductive paths at least partially blocking the negative ion beam;

wherein during use first electric field lines run between said first focusing electrode and said second focusing electrode,

wherein during use the negative ions encounter first force vectors running up the first electric field lines that focus the negative ion beam,

wherein said first focusing electrode and said second focusing electrode comprises opposite charge.

5. The apparatus of claim 4, wherein said metal conductive paths comprise any of:

a series of conductive lines running substantially in parallel across the negative ion beam;

a conductive grid crossing the negative ion beam; and

a focusing foil crossing the negative ion beam, said focusing foil having holes, said holes comprising a combined cross-sectional area of at least ninety percent of the cross-sectional area of the negative ion beam.

6. The apparatus of claim 5, further comprising:

a third focusing electrode circumferentially surrounding the negative ion beam, wherein said second focusing electrode comprises a position between said first focusing electrode and said third focusing electrode,

wherein during use said third focusing electrode comprises a negative charge,

wherein during use second electric field lines run between said third focusing electrode and said second focusing electrode,

wherein during use the negative ions encounter second force vectors running up the second electric field lines that focus the negative ion beam.

7. The apparatus of claim 1, wherein said negative ion source further comprises:

a magnetic material configured to produce a magnetic field loop,

wherein the magnetic field loop yields a magnetic barrier between a high temperature plasma chamber and a low temperature plasma region,

wherein said magnetic barrier selectively passes elements of plasma in said high temperature plasma chamber to said low temperature plasma region,

wherein low energy electrons interact with atomic hydrogen to create hydrogen anions in said low temperature plasma region;

wherein application of a high voltage pulse extracts negative ions from said negative ion source to form the negative ion beam.

8. The apparatus of claim 1, wherein said negative ion source further comprises:

a magnetic field barrier separating a high energy plasma region from a low temperature plasma zone.

9. The apparatus of claim 8, wherein a magnetic material within said high energy plasma region generates the magnetic field barrier.

10. The apparatus of claim 9, further comprising:

a first ion generation electrode at a first end of said high temperature plasma chamber; and

a second ion generation electrode at a second end of said high temperature plasma chamber,

wherein application of a first high voltage pulse across said first ion generation electrode and said second ion generation electrode breaks hydrogen in said high temperature plasma chamber into component parts.

11. The apparatus of claim 10, further comprising a third ion generation electrode, wherein application of a second high voltage pulse across said second ion generation electrode and said third ion generation electrode extracts negative ions from the low temperature plasma zone to form the negative ion beam.

12. The apparatus of claim 11, further comprising a magnetic field carrying outer wall about said high energy plasma region,

wherein said magnetic material yields a magnetic field loop running through said first ion generation electrode, through said magnetic field carrying outer wall, through said second ion generation electrode, across a gap, and through said magnetic material.

13. The apparatus of claim 1, wherein said accelerator comprises a synchrotron, said synchrotron comprising:

an extraction material;

at least a one kilovolt direct current field applied across a pair of extraction blades; and

a deflector,

wherein during use the charged particle beam passes through said extraction material resulting in a reduced energy charged particle beam,

wherein the reduced energy charged particle beam passes between said pair of extraction blades, and

wherein the direct current field redirects the reduced energy charged particle beam out of said synchrotron through said deflector,

wherein said deflector yields an extracted charged particle beam.

14. The apparatus of claim 13, further comprising an intensity controller controlling intensity of the extracted charged particle beam via a feedback control.

15. The apparatus of claim 14, wherein during use an induced current results from the charged particle beam passing through said extraction material, wherein the induced current comprises a feedback input to said intensity controller.

16. The apparatus of claim 13, further comprising an X-ray source located within less than about fifty millimeters of the extracted charged particle beam, wherein said X-ray source maintains position during use of said X-ray source, wherein said X-ray source maintains position during tumor treatment with the extracted charged particle beam.

17. The apparatus of claim 1, wherein said irradiation device further comprises:

a rotatable platform rotating during an irradiation period;

an immobilization system mounted on said first rotatable platform, wherein said immobilization system restricts tumor motion during delivery of the extracted charged particle beam,

wherein said rotatable platform rotates to at least ten irradiation positions during tumor irradiation with the extracted charged particle beam.

18. A method for injecting a charged particle beam into an accelerator of an irradiation device, said irradiation device irradiating a tumor during use, said method comprising the steps of:

producing negative ions in a negative ion beam with a negative ion source;

converting the negative ion beam into the charged particle beam with a converting foil, said converting foil providing a vacuum barrier between the negative ion source and said accelerator, wherein said accelerator comprises a synchrotron; and

injecting the charged particle beam into said accelerator.

19. The method of claim 18, wherein said converting foil comprises:

a beryllium carbon film, wherein said carbon film comprises a thickness of about thirty to two hundred micrometers.

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

circumferentially surrounding the negative ion beam with a first focusing electrode;

providing a second focusing electrode, said second focusing electrode comprising metal conductive paths at least partially blocking the negative ion beam;

wherein first electric field lines run between said first focusing electrode and said second focusing electrode,

wherein the negative ions encounter first force vectors running up said first electric field lines that focus the negative ion beam,

wherein said first focusing electrode and said second focusing electrode comprises opposite charges; and

focusing the negative ion beam using the first electric field lines, wherein the first electric field lines run in a vacuum system, through the negative ion beam.

21. The method of claim 20, wherein said metal conductive paths comprise any of:

a series of wires running substantially in parallel across the negative ion beam;

a conductive grid crossing the negative ion beam; and

a focusing foil crossing the negative ion beam, said focusing foil having holes, said holes comprising a combined cross-sectional area of at least ninety percent of the cross-sectional area of the negative ion beam.

22. The method of claim 20, further comprising the step of:

circumferentially surrounding the negative ion beam with a third focusing electrode, wherein said second focusing electrode comprises a position between said first focusing electrode and said third focusing electrode,

wherein second electric field lines run between said third focusing electrode and said second focusing electrode,

wherein the negative ions encounter second force vectors running up said second electric field lines that focus the negative ion beam.

23. The method of claim 20, further comprising the step of:

producing a magnetic field loop with a magnetic material at least partially located inside said negative ion source, wherein said magnetic field loop yields a magnetic barrier between a high temperature plasma chamber and a low temperature plasma region, wherein said magnetic barrier selectively passes elements of plasma in said high temperature plasma chamber to said low temperature plasma region, wherein low energy electrons interact with atomic hydrogen to create hydrogen anions in said low temperature plasma region; and

applying a high voltage pulse across said low temperature plasma region to extract negative ions from said negative ion source to form the negative ion beam.

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

applying a first high voltage pulse across a first ion generation electrode at a first end of said high temperature plasma chamber and a second ion generation electrode at a second end of said high temperature plasma chamber,

wherein application of said first high voltage pulse across said first ion generation electrode and said second ion generation electrode breaks hydrogen in said high temperature plasma chamber into component parts,

wherein said first high voltage pulse comprises a pulse of at least four kilovolts for a period of at least fifteen microseconds.

25. The method of claim 24, further comprising the steps of:

applying a second high voltage pulse across the low temperature plasma zone with an extraction electrode,

wherein said second high voltage pulse comprises a pulse of at least twenty kilovolts during a period overlapping the last five microseconds of said first high voltage pulse,

wherein said second high voltage pulse comprises a pulse of at least twenty kilovolts during a period overlapping at least three microseconds of said first high voltage pulse, and

providing a second high voltage pulse across said second ion generation electrode and a third ion generation electrode, wherein application of the second high voltage pulse extracts negative ions from the low temperature plasma zone to form the negative ion beam.

26. The method of claim 18, further comprising the step of:

extracting the charged particle beam from said accelerator, said step of extracting comprising the steps of;

transmitting the charged particle beam through an extraction material, said extraction material yielding a reduced energy charged particle beam;

applying an extraction field of at least five hundred volts across a pair of extraction blades;

passing the reduced energy charged particle beam between said pair of extraction blades,

wherein said extraction field redirects the reduced energy charged particle as an energy controlled extracted charged particle beam.

27. The method of claim 26, further comprising the step of:

controlling intensity of the extracted charged beam with an intensity controller.

28. The method of claim 27, wherein said step of controlling comprises the steps of:

inputting a feedback signal to said intensity controller, said step of transmitting yielding emitted electrons in the process of the charged particle beam striking said extraction material, wherein the emitted electrons are converted to said feedback signal;

comparing said feedback signal to an irradiation plan intensity;

adjusting betatron oscillation with said intensity controller until said feedback signal proximately equals said irradiation plan intensity,

wherein said energy controlled extracted charged particle beam comprises an independent intensity control.

29. The method of claim 26, further comprising the step of:

generating a tumor X-ray image using an X-ray source located within less than about fifty millimeters of the extracted charged particle beam, wherein said X-ray source maintains position during use of said X-ray source and said X-ray source maintaining a static position during tumor treatment with the extracted charged particle beam.

30. The method of claim 29, further comprising the steps of:

rotating a rotatable platform of said irradiation device during an irradiation period;

providing an immobilization system mounted on said first rotatable platform, wherein said immobilization system restricts tumor motion during delivery of the charged particle beam; and

irradiating the tumor with said irradiation device, wherein said rotatable platform rotates to at least ten irradiation positions during said step of irradiating.