CORPUSCULAR RAY ENERGY CHANGING DEVICE AND CORPUSCULAR RAY IRRADIATION DEVICE

摘要

PROBLEM TO BE SOLVED: To impart optimum dose distribution to individual patients by providing a corpuscular ray energy changing member of structure different in passing length according to the incident place of corpuscular rays, and arranging the energy changing member periodically to constitute an energy changing filter. SOLUTION: A support part 61 for supporting a ridge filter 14 of a stepped wedge structure body which is an energy changing member absorbing corpuscular ray energy according to the incident position is rotated by the actuation of a driving motor 64 through a driving force transmission part 62. The step height and width of the ridge filter 14 are designed to make dose distribution flat from the position and weight of each Bragg curve in a position where the ridge filter 14 is rotated by a certain angle (θ=45 deg., for instance) from a Bragg curve in the water. The ridge filter 14 is thus rotated to make a dose distribution range continuously variable so as to reduce the required number of ridge filters.