Particle therapy system

A particle therapy system comprising an accelerator for accelerating a charged-particle beam to a set level of energy, and a rotating irradiation facility for irradiating the charged-particle beam extracted from said accelerator, said irradiation facility comprising beam transport apparatus for transporting the charged-particle beam extracted from said accelerator, and irradiation field forming apparatus for forming an irradiation field of the charged-particle beam transported by said beam transport apparatus,

• wherein said irradiation field forming apparatus includes beam scanning apparatus for scanning the charged-particle beam;
• and
• wherein said particle therapy system further comprises:
• first beam position detecting apparatus arranged along an orbit of the charged-particle beam upstream of said beam scanning apparatus, and detecting a position at which the charged-particle beam passes;
• second beam position detecting apparatus arranged along the orbit of the charged-particle beam downstream of said beam scanning apparatus, and detecting a position at which the charged-particle beam passes;
• a first steering magnet and a second steering magnet both provided in said first beam transport apparatus upstream of said first beam position detecting apparatus;
• displacement amount computing apparatus for determining respective displacement amounts by which the position of the charged-particle beam is to be displaced by said first and second steering magnets, in accordance with detected signals outputted from said first and second beam position detecting apparatus;
• and
• control system for controlling respective excitation currents of said first and second steering magnets in accordance with said respective displacement amounts.

A method of adjusting an orbit of a charged-particle beam in a particle therapy system comprising an accelerator for accelerating a charged-particle beam to a set level of energy, and a rotating irradiation facility for irradiating the charged-particle beam extracted from said accelerator, said irradiation facility comprising a beam transport apparatus having first and second steering magnets for transporting the charged-particle beam extracted from said accelerator, and irradiation field forming apparatus for forming an irradiation field forming apparatus for forming an irradiation field of the charged-particle beam transported by said beam transport apparatus, wherein said method comprises the steps of:

• detecting a first passing position at which the charged-particle beam passes, downstream of a bending magnet arranged most downstream in said beam transport apparatus;
• detecting a second passing position at which the charged-particle beam passes, downstream of a position where said first passing position is detected;
• computing respective displacement amounts by which the position of the charged-particle beam is to be displaced by said first and second steering magnets, in accordance with said detected first and second passing positions by using a displacement amount computing apparatus;
• and
• controlling respective excitation currents of said first and second steering magnets in accordance with said respective displacement amounts.

A method of adjusting an orbit of a charged-particle beam in a particle therapy system comprising an accelerator for accelerating a charged-particle beam to a set level of energy, a rotating irradiation facility for irradiating the charged-particle beam extracted from said accelerator, and a beam transport apparatus having first and second steering magnets for transporting the charged-particle beam extracted from said accelerator to said irradiation facility, wherein said method comprises the steps of:

• detecting a first passing position at which the charged-particle beam passes, at a position where said beam transport apparatus is present;
• detecting a second passing position at which the charged-particle beam passes, downstream of a position where said first passing position is detected;
• computing respective displacement amounts by which the position of the charged-particle beam is to be displaced by said first and second steering magnets, in accordance with said detected first and second passing positions by using a displacement amount computing apparatus;
• and
• controlling respective excitation currents of said first and second steering magnets in accordance with said respective displacement amounts.