Patent ID: 7439528

Claim:
A particle therapy system comprising: a circular accelerator for accelerating a charged particle beam, said circular accelerator including a cavity for applying a radio frequency wave to accelerate the charged particle beam; a charged particle beam irradiation apparatus for irradiating the charged particle beam extracted from said circular accelerator to an irradiation target; a frequency counter for measuring the frequency of said radio frequency wave applied by said cavity to accelerate the charged particle beam or the revolution frequency of the charged particle beam orbiting within said circular accelerator; a radial beam position measuring device for measuring the orbit position of the charged particle beam orbiting within said circular accelerator; 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 and before extraction of the charged particle beam from said circular accelerator, and wherein said energy determination device determines the energy of the charged particle beam orbiting within said circular accelerator based on the frequency of the radio frequency wave or the revolution frequency of the charged particle beam measured by said frequency counter after the end of the acceleration, and the orbit position of the charged particle beam measured by said radial beam position measuring device after the end of the acceleration.