Patent ID: 7875868

Claim:
A charged particle beam irradiation system comprising: a charged particle beam generator for accelerating and extracting a charged particle beam; a beam transport line for transporting the charged particle beam extracted from the charged particle beam generator, said beam transport line being connected to the charged particle beam generator; and at least one irradiation nozzle for irradiating an affected part of a patient with the charged particle beam; wherein said charged particle beam irradiation system further comprises: a beam dump device including: a steering magnet that is disposed on the beam transport line; and a beam dump that is disposed on a beam path branching from the steering magnet, said beam dump device performing the excitation control of the steering magnet such that from among charged particle beams extracted from the charged particle beam generator, a charged particle beam which is not to be transported to the irradiation nozzle is applied to the beam dump; and a dose monitoring device disposed in the beam dump device for measuring the dose of the charged particle beam applied to the beam dump.