Patent ID: 8436323

Claim:
A particle beam irradiation apparatus comprising: a beam generation unit that generates a particle beam; a beam emission control unit that controls emission of the particle beam; a beam scanning instruction unit that sequentially two-dimensionally instructs a position of the particle beam so that the particle beam is scanned across an entire slice, the slice being obtained by dividing an affected region to be irradiated in an axis direction of the particle beam; a beam scanning unit that two-dimensionally scans the particle beam based on an instruction signal from the beam scanning instruction unit; a respiration measurement unit that obtains an amount of movement of the affected region of a patient or a respiration waveform of a patient; a respiration gate generation unit that generates a respiration gate synchronized with a respiration cycle of the patient based on a signal output from the respiration measurement unit; and a pulse generation unit that generates a predetermined number of scanning start pulses at substantially equally spaced time intervals in the respiration gate, the predetermined number of the scanning start pulses corresponding to a predetermined number of scans repeated in a same slice, and each of the time intervals being determined by dividing a width of the respiration gate by the number of the scans repeated in the respiration gate so that the number of the scans in each respiration gate is maintained between different respiration cycles, wherein, the beam scanning instruction unit instructs to scan the entire slice by pattern irradiation based on a set dose from each of the scanning start pulses so that a scan of the same slice is repeated the predetermined number of times, and the beam emission control unit permits emission of the particle beam only in the respiration gate, and emits the particle beam from each of the scanning start pulses until the pattern irradiation based on the set dose is completed.