ION BEAM FOCUSING LENS METHOD AND APPARATUS USED IN CONJUNCTION WITH A CHARGED PARTICLE CANCER THERAPY SYSTEM

• US 20100133446A1
• Filed: 09/22/2009
• Published: 06/03/2010
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Andrey Vladimirovich Balakin, Pavel Vladimirovich Balakin
• Original Assignee: Viadimir Balakin
• Inventors: Balakin, Vladimir
• Granted Patent: US 8,093,564 B2
• Time in Patent Office: Days
• US Class Current: 250/397
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/10 X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy A61N5/01 takes precedence
• CPC Class Codes: A61N 5/1082 having multiple beam rotation axes
• CPC Class Codes: G21K 1/08 Deviation, concentration or focusing of the beam by electric or magnetic means electron-optical arrangements in electric discharge tubes H01J29/46; details, e.g. electric or magnetic deviating means for direct voltage accelerators or in accelerators using single pulses H05H5/02; arrangements for injecting particles into orbits H05H7/08; arrangements for ejecting particles from orbits H05H7/10
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 7/10 Arrangements for ejecting particles from orbits

Abstract

The invention comprises an ion beam focusing method and apparatus used as part of an ion beam injection system, which is used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. The ion beam focusing system includes two or more electrodes where one electrode of each electrode pair partially obstructs the ion beam path with conductive paths, such as a conductive mesh. In a given electrode pair, electric field lines, running between the conductive mesh of a first electrode and a second electrode, provide inward forces focusing the negative ion beam. Multiple such electrode pairs provide multiple negative ion beam focusing regions.

Claims

1. An apparatus for focusing negative ions in an injector, said injector injecting the particle beam into an accelerator of an irradiation device, said irradiation device irradiating a tumor during use, said apparatus comprising:

a negative ion source configured to produce the negative ions in a negative ion beam path;

an ion beam focusing lens, comprising;

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

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

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 the first electric field lines that focus the negative ions.

2. The apparatus of claim 1, wherein said first focusing electrode and said second focusing electrode comprise oppositely signed charges.

3. The apparatus of claim 1, wherein said metal conductive paths comprise any of:

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

a conductive grid crossing the negative ion beam path; and

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

4. The apparatus of claim 1, wherein said metal conductive paths block less than ten percent of a radial cross-sectional area of the negative ions traveling through the negative ion beam path.

5. The apparatus of claim 1, further comprising:

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

wherein said third focusing electrode comprises a negative charge,

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 the second electric field lines that focus the negative ions.

6. The apparatus of claim 1, further comprising:

a converting foil, 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 proton beam.

7. The apparatus of claim 1, further comprising:

a converting foil in the negative ion beam path,

wherein said converting foil provides a pressure seal between an ion beam formation side chamber of said irradiation device and a synchrotron side chamber of said irradiation device, wherein a first pump system operates to maintain a first vacuum in said ion beam formation side chamber of said converting foil, wherein a second pump system operates to maintain a second vacuum in said synchrotron side chamber.

8. The apparatus of claim 7, wherein said converting foil comprises:

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

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

a magnetic material producing 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 first high voltage pulse extracts negative ions from said negative ion source to form the negative ions.

10. The apparatus of claim 1, further comprising:

a first ion generation electrode at a first end of a high temperature plasma chamber in said negative ion source;

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

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

11. A method for focusing negative ions in an irradiation device, said irradiation device irradiating a tumor during use, said method comprising the steps of:

producing the negative ions in a negative ion beam path with a negative ion source,

focusing the negative ions using first electric field lines in an ion beam focusing lens, said step of focusing further comprising the steps of;

circumferentially surrounding the negative ion beam path 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 path;

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

wherein the negative ions encounter first force vectors running up the first electric field lines that focus the negative ions.

12. The method of claim 11, wherein said metal conductive paths comprise any of:

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

a conductive grid crossing the negative ion beam path; and

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

13. The method of claim 11, further comprising the step of:

circumferentially surrounding the negative ion beam path 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 the second electric field lines that focus the negative ions.

14. The method of claim 11, further comprising the steps of:

converting the negative ions into a proton beam with a converting foil, said converting foil positioned in the ion beam path between said negative ion source and an accelerator; and

providing a vacuum barrier between the negative ions and said accelerator with said converting foil, wherein said accelerator comprises a synchrotron.

15. The method of claim 11, further comprising the steps 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 in said injector and a low temperature plasma region in said injector, 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 the negative ions from said negative ion source.

16. An apparatus for delivering charged particles in a negative ion beam path of an injector in an irradiation device as a charged particle beam accelerated in a synchrotron, said apparatus comprising:

an ion beam focusing lens, comprising;

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

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

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

wherein the charged encounter first force vectors running up the first electric field lines yielding focused charged particles.

17. The apparatus of claim 16, further comprising:

an injector configured to inject the focused charged particles into said synchrotron as the charged particle beam, said synchrotron further comprising,

an extraction material;

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

a deflector,

wherein 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.

18. The apparatus of claim 16, further comprising:

an intensity controller controlling intensity of an extracted charged particle beam from said synchrotron via a feedback control,

wherein an induced current results from the charged particle beam passing through an extraction material,

wherein the induced current comprises a feedback input to said intensity controller.

19. The apparatus of claim 16, further comprising:

an X-ray source located within about twenty millimeters of an extracted charged particle beam from said synchrotron,

wherein said X-ray source maintains a first position during use of said X-ray source,

wherein said X-ray source maintains said first position during tumor treatment with the extracted charged particle beam.

20. The apparatus of claim 16, 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 an extracted charged particle beam from said synchrotron,

wherein said rotatable platform rotates to at least ten irradiation positions during tumor irradiation with the charged particle beam after extraction from said synchrotron.