Abstract: In a radiation emitting device, particularly in a radiation treatment device (2), the radiation treatment for an object (13) via a radiation beam (1) is determined. The field on the object to be irradiated is inputted and then divided up into sections (220-230). Plates or a collimator are arranged between a radiation source and an object (13) to provide an opening over one of sections (220). A radiation beam (1) is generated and used to treat one of sections (220) with radiation. This is repeated until each of sections (220-230) are treated with radiation.