this is a new technique of producing high energy x - rays for radiation therapy at a patient &# 39 ; s level . the dose delivery system uses a linear accelerator with no flattening filter . the technique improves patient radiation therapy by reducing radiation scattered to surrounding normal tissue and reducing electron contamination . it increases dose rate to shorten treatment time . the flattening filter reduces the efficiency of the beam by reducing the fluence and increasing scattered radiation . this technique involves removal of the flattening filter . it uses inverse planning to shape the dose distribution .