Dynamic beam flattening apparatus for radiation therapy

摘要

A radiation therapy apparatus includes a compensator having a plurality of leaves to divide a radiation beam into rays each of which may be effectively and individually attenuated over a range of attenuations by controlling the ratio of time in which each leaf is in the open and closed states. The compensator is used to compensate for the non-uniform source fluence profile of the radiation beam. In a second embodiment, a radiation therapy apparatus includes an oscillating means for oscillating an electron stream along a line on a radiation generating target so that the resulting field of radiation emanating from the target within the plane of oscillation is uniform over time. The invention eliminates the need for beam flattening filters and thus more effectively uses the energy of the radiation beam.