Patent ID: 9415241
Filing Date: 2016-08-16
CPC Classification: A61N

Claim Text:
1. A charged particle beam irradiation system comprising: an ion source generating charged particles and an accelerator configured to accelerate and extract a charged particle beam; a scanning electromagnet configured to scan the accelerated charged particle beam; a controller, coupled to the scanning electromagnet, programmed to divide an irradiation target into a plurality of layers in a traveling direction of the charged particle beam and set a plurality of irradiation spots in the plurality of layers; a beam irradiation apparatus, coupled to the controller, configured to irradiate the accelerated charged particle beam to the plurality of irradiation spots respectively set for the plurality of layers; a beam radiation dose monitor, coupled to the controller, configured to obtain a dose of the charged particle beam passing through the beam irradiation apparatus; and a beam position monitor, coupled to the controller, configured to obtain at least one of a position and a width of the charged particle beam scanned by the scanning electromagnet, wherein the beam position monitor obtains at least one of the position and the width of the charged particle beam for each irradiation spot, wherein the controller is programmed to: determine whether the at least one of the position and the width of the charged particle beam obtained for each irradiation spot is within a first allowable range, divide one or more of the plurality of irradiation spots into a plurality of splits and obtain at least one of the position and the width of the charged particle beam for each split, determine whether the at least one of the position and the width of the charged particle beam of a split of an irradiation spot of the one or more of the plurality of irradiation spots is within a second allowable range, and after the determination of whether the least one of the position and the width of the charged particle beam of the split is within the second allowable range, determine whether the at least one of the position and the width of the charged particle beam of a subsequent split of the irradiation spot is within the second allowable range, and stop irradiation of the charged particle beam when the at least one of the position and the width of the charged particle beam for a split of the splits of an irradiation spot is not within the second allowable range, wherein the beam irradiation apparatus is configured to irradiate the plurality of irradiation spots in accordance with the results of the determinations for each of the first allowable range and the second allowable range.