Charged particle beam extraction method and apparatus used in conjunction with a charged particle cancer therapy system
First Claim
1. An apparatus for extracting a circulating charged particle beam from a synchrotron, said synchrotron having a center, said apparatus comprising:
- an extraction material;
at least a one kilovolt direct current field applied across a pair of extraction blades;
a deflector;
a patient respiration monitor generating a respiration signal; and
a main controller, wherein the circulating 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, wherein the direct current field redirects the reduced energy charged particle beam through said deflector, wherein said deflector yields an extracted charged particle beam, wherein said extraction material comprises a foil less than about one hundred fifty micrometers thick, wherein a radio frequency voltage applied across a first pair of blades is configured to induce a betatron oscillation on the circulating charged particle beam, wherein a first distance between said center of said synchrotron and said pair of extraction blades is less than a second distance between said center of said synchrotron and said pair of first blades, wherein the circulating charged particle beam comprises a radius of curvature passing through said first pair of blades, wherein the reduced energy charged particle beam, resulting from transmission through said extraction material, comprises a radius of curvature passing through said extraction blades, wherein timing of the extracted charged particle beam is synchronized to said respiration signal, and said main controller timing all of;
(1) particle beam injection, (2) particle beam acceleration, and (3) timing of said radio frequency voltage to synchronize with said respiration signal.
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Accused Products
Abstract
The invention comprises a charged particle beam extraction method and apparatus used in conjunction with charged particle beam radiation therapy of cancerous tumors. The system uses a radio-frequency cavity system to induce betatron oscillation of a charged particle stream. Sufficient amplitude modulation of the charged particle stream causes the charged particle stream to hit a material, such as a foil. The foil decreases the energy of the charged particle stream, which decreases a radius of curvature of the charged particle stream in the synchrotron sufficiently to allow a physical separation of the reduced energy charged particle stream from the original charged particle stream. The physically separated charged particle stream is then removed from the system by use of an applied field and deflector.
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Citations
33 Claims
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1. An apparatus for extracting a circulating charged particle beam from a synchrotron, said synchrotron having a center, said apparatus comprising:
- an extraction material;
at least a one kilovolt direct current field applied across a pair of extraction blades;
a deflector;
a patient respiration monitor generating a respiration signal; and
a main controller, wherein the circulating 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, wherein the direct current field redirects the reduced energy charged particle beam through said deflector, wherein said deflector yields an extracted charged particle beam, wherein said extraction material comprises a foil less than about one hundred fifty micrometers thick, wherein a radio frequency voltage applied across a first pair of blades is configured to induce a betatron oscillation on the circulating charged particle beam, wherein a first distance between said center of said synchrotron and said pair of extraction blades is less than a second distance between said center of said synchrotron and said pair of first blades, wherein the circulating charged particle beam comprises a radius of curvature passing through said first pair of blades, wherein the reduced energy charged particle beam, resulting from transmission through said extraction material, comprises a radius of curvature passing through said extraction blades, wherein timing of the extracted charged particle beam is synchronized to said respiration signal, and said main controller timing all of;
(1) particle beam injection, (2) particle beam acceleration, and (3) timing of said radio frequency voltage to synchronize with said respiration signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- an extraction material;
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15. An apparatus for extracting a circulating charged particle beam from a synchrotron, said synchrotron having a center, said apparatus comprising:
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an extraction material; at least a one kilovolt direct current field applied across a pair of extraction blades; a deflector, wherein the circulating 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, wherein the direct current field redirects the reduced energy charged particle beam through said deflector, wherein said deflector yields an extracted charged particle beam, wherein said extraction material comprises any of; beryllium; lithium hydride; and carbon, and wherein said extraction material comprises a foil of about thirty to one hundred micrometers thickness. - View Dependent Claims (16)
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17. A method for extracting a circulating charged particle beam from a synchrotron, comprising the steps of:
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transmitting the circulating charged particle beam through an extraction material, said extraction material yielding a reduced energy charged particle beam, wherein said extraction material comprises any of; beryllium; lithium hydride; and carbon, and wherein said extraction material comprises a foil of about forty to sixty microns thickness; applying at least five hundred volts across a first pair of blades; and passing the reduced energy charged particle beam between said first pair of blades, wherein said first pair of blades redirect the reduced energy charged particle beam to a deflector, and wherein said deflector yields an extracted charged particle beam. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for extracting a circulating charged particle beam from a synchrotron, comprising the steps of:
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providing a turning magnet in said synchrotron, said turning magnet wound by a winding coil and a correction coil; providing a first current to said winding coil and a second current to said correction coil, said second current less than ten percent of said first current; generating a feedback signal using a magnetic field sensor, said magnetic field sensor proximate said turning magnet; stabilizing a magnetic field about said turning magnet using said feedback signal in control of said second current applied to said correction coil; after said step of stabilizing the magnetic field, transmitting the circulating charged particle beam through an extraction material, said extraction material yielding a reduced energy charged particle beam; applying a 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 field redirects the reduced energy charged particle as an extracted charged particle beam. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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Specification