摘要 |
When an energy of a particle beam to be emitted from an accelerator (1) is set for every slice group (F) including two or more adjacent slices (S) and an attenuation amount is set for each slice (S) in the slice group(F), the energy to be emitted from the accelerator (1) is set, for every slice group (F), higher than an energy corresponding to the slice (S) at a deepest location in that slice group (F) so that a transmissive plate has a predetermined thickness for the slice (S) at the deepest location; and, with respect to a thickness of the transmissive plate to be set for every slice group (F), the thickness set for the slice group (F) at a deep location is larger than or equal to the thickness set for the slice group (F) at a shallow location, and the thickness set for the slice group (F) at a deepest location is thicker than the thickness set for the slice group (F) at a shallowest location. |