Patent ID: 8552408

Claim:
A particle beam irradiation apparatus that directs a particle beam to an affected area of a patient, the particle beam irradiation apparatus comprising: an emission control portion that controls emission and termination of the particle beam; a control portion that sequentially changes an irradiation position of the particle beam for the affected area; first and second dosimeters that measure dose rates of the particle beam directed to the affected area; and an abnormality determination portion that uses dose measurement values obtained by accumulating the dose rates output from the first and second dosimeters to perform abnormality determination of the apparatus and that outputs, to the emission control portion, an interlock signal for terminating the emission of the particle beam when determining that there is an abnormality, wherein the control portion accumulates the dose rate output from the first dosimeter for each of irradiation positions of the particle beam to calculate a first beam dose measurement value and changes the irradiation position of the particle beam when the first beam dose measurement value reaches a first planned dose value predetermined for each of the irradiation positions, and the abnormality determination portion performs: first abnormality determination of accumulating the dose rate output from the second dosimeter for each of the irradiation positions of the particle beam to calculate a second beam dose measurement value and determining that there is the abnormality if the second beam dose measurement value exceeds a second planned dose value that is set to a value higher than the first planned dose value when the first beam dose measurement value reaches the first planned dose value; and second abnormality determination of accumulating the dose rates output from the first and second dosimeters for each of predetermined determination periods to calculate sectional dose measurement values and determining that there is the abnormality based on the sectional dose measurement values.