A curved movable beam-stop array which has a generator, a curved grid and a controller. The generator generates radiation beams while rotating to a gantry angle. The curved grid is positioned in the radiation direction of the radiation beams generated from the generator. The controller controls operations of the grid. A plurality of slits of the grid are spaced apart from each other at a predetermined distance and allow at least a portion of the radiation beams generated from the generator to pass through. The controller moves the slit by a predetermined distance when the generator moves by a predefined angle.
