Patent ID: 8487286

Claim:
Radiation therapy equipment including a radiation collimator unit for setting a desired irradiation field onto a target treating region by shielding radiation on unnecessary regions, the radiation therapy equipment comprising: a pair of movable collimator blocks, each block including a plurality of movable leaf plates, each leaf plate having a toothed configuration on an arc shaped tracking surface on the leaf plate; a plurality of driving gears configured to independently drive each of the plurality of leaf plates by engaging with the toothed configuration provided on each tracking surface of the plurality of leaf plates; a plurality of constant force spring units coupled to each of the plurality of driving gears configured to constantly apply a direct force to each of the plurality of driving gears so as to independently move each of the plurality of leaf plates in closing directions; a plurality of wires connected to each of the plurality of leaf plates; and a plurality of roll-up units configured to independently roll-up each of the plurality of wires so as to independently move each of the leaf plates in an opening direction against each of the closing forces of the plurality of constant force spring units.