Patent attributes
A particle therapy system capable of measuring energy of a charged particle beam even during irradiation of the charged particle beam is provided. A beam delivery (irradiation) system comprises a block collimator constituted by a pair of collimator members, and an energy detector mounted to one of the collimator members to be disposed on the upstream side thereof. When the pair of collimator members are moved in directions away from each other, a beam passage is formed between them. The energy detector constitutes an energy measuring device together with a signal processing unit. A part of the ion beam having reached the interior of the irradiation nozzle is irradiated to a patient through the beam passage. When a part of the remaining ion beam enters the energy detector, electric charges generate in the energy detector. The signal processing unit determines energy of the ion beam based on a position within the energy detector at which electric charges have generated in maximum amount.
