Particle therapy system

• US 20050099145A1
• Filed: 11/05/2004
• Published: 05/12/2005
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nishiuchi, Hideaki, Matsuda, Koji, Umezawa, Masumi, Ike, Katsuhisa
• Granted Patent: US 7,439,528 B2
• Time in Patent Office: Days
• US Class Current: 315/500
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: H05H 13/04 Synchrotrons
• CPC Class Codes: H05H 2007/008 for measuring beam parameters
• CPC Class Codes: H05H 7/06 Two-beam arrangements; Multi-beam arrangements storage rings; Electron rings

Abstract

A particle therapy system capable of confirming energy of an accelerated charged particle beam before the charged particle beam is irradiated to an irradiation target. A beam position monitor is disposed in a synchrotron, and a cavity voltage monitor is associated with an RF cavity for acceleration. An ion beam orbiting within the synchrotron is accelerated with application of an RF voltage applied to the RF cavity and is extracted from the synchrotron with application of an RF voltage applied to an RF knockout electrode. Based on a cavity voltage signal detected by the cavity voltage monitor, a frequency counter measures the frequency of the RF voltage applied to the RF cavity. Based on a voltage detected by the beam position monitor, a beam signal processing unit measures the position of a beam orbit. Based on the frequency of the RF voltage and the position of the beam orbit, the energy judgment processing unit determines whether energy of the ion beam after the end of the acceleration is normal or abnormal.

Claims

1. A particle therapy system comprising:

a circular accelerator for accelerating a charged particle beam;

a charged particle beam irradiation apparatus for irradiating the charged particle beam extracted from said circular accelerator to an irradiation target; and

an energy determination device for determining energy of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator.

2. A particle therapy system according to claim 1, wherein said circular accelerator include a cavity for applying a radio frequency wave to accelerate the charged particle beam, and

said energy determination device determines that the energy of the charged particle beam orbiting after the end of the acceleration is normal, when a frequency of said radio frequency wave after the end of the acceleration is within a first allowable range and an orbit position of the orbiting charged particle beam after the end of the acceleration is within a second allowable range.

3. A particle therapy system according to claim 1, wherein said circular accelerator include a cavity for applying a radio frequency wave to accelerate the charged particle beam, and

said energy determination device determines that the energy of the charged particle beam orbiting after the end of the acceleration is abnormal, when a frequency of said radio frequency wave after the end of the acceleration is outside a first allowable range or an orbit position of the orbiting charged particle beam after the end of the acceleration is outside a second allowable range.

4. A particle therapy system according to claim 2, further comprising a frequency counter for measuring the frequency of said radio frequency wave, and a radial beam position measuring device for measuring the orbit position of the charged particle beam.

5. A particle therapy system according to claim 1, wherein said circular accelerator include a bending magnet, and

said energy determination device determines that the energy of the charged particle beam orbiting after the end of the acceleration is normal, when the strength of a bending magnetic field produced by said bending magnet is within a first allowable range and an orbit position of the orbiting charged particle beam is within a second allowable range.

6. A particle therapy system according to claim 1, wherein said circular accelerator include a bending magnet, and

said energy determination device determines that the energy of the charged particle beam orbiting after the end of the acceleration is abnormal, when the strength of a bending magnetic field produced by said bending magnet is outside a first allowable range and an orbit position of the orbiting charged particle beam is outside a second allowable range.

7. A particle therapy system according to claim 5, further comprising a bending magnetic field strength measuring device for measuring the strength of the bending magnetic field, and a radial beam position measuring device for measuring the orbit position of the charged particle beam.

8. A particle therapy system according to claim 1, further comprising a beam intensity determination device for determining beam intensity of the charged particle beam orbiting within said circular accelerator after the end of acceleration of the charged particle beam by said circular accelerator.

9. A particle therapy system according to claim 8, wherein said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting after the end of the acceleration is normal, when the beam intensity is within a third allowable range.

10. A particle therapy system according to claim 8, wherein said beam intensity determination device determines that the beam intensity of the charged particle beam orbiting after the end of the acceleration is abnormal, when the beam intensity is outside a third allowable range.

11. A particle therapy system according to claim 1, further comprising a first safety device for permitting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is normal, and for inhibiting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is abnormal.

12. A particle therapy system according to claim 8, further comprising a second safety device for permitting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the orbiting charged particle beam is normal, and for inhibiting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the orbiting charged particle beam is abnormal.

13. A particle therapy system according to claim 2, further comprising a first safety device for permitting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is normal.

14. A particle therapy system according to claim 3, further comprising a first safety device for inhibiting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is abnormal.

15. A particle therapy system according to claim 9, further comprising a second safety device for permitting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the orbiting charged particle beam is normal.

16. A particle therapy system according to claim 10, further comprising a second safety device for inhibiting extraction of the charged particle beam from said circular accelerator when said beam intensity determination device determines that the beam intensity of the orbiting charged particle beam is abnormal.

17. A particle therapy system according to claim 3, further comprising a frequency counter for measuring the frequency of said radio frequency wave, and a radial beam position measuring device for measuring the orbit position of the charged particle beam.

18. A particle therapy system according to claim 6, further comprising a bending magnetic field strength measuring device for measuring the strength of the bending magnetic field, and a beam orbit position measuring device for measuring the orbit position of the charged particle beam.

19. A particle therapy system according to claim 5, further comprising a first safety device for permitting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is normal.

20. A particle therapy system according to claim 6, further comprising a first safety device for inhibiting extraction of the charged particle beam from said circular accelerator when said energy determination device determines that the energy of the orbiting charged particle beam is abnormal.