The present relates to a device for providing a radiation treatment to a patient comprising :- an electron source for providing a beam of electrons, and- a linear accelerator for accelerating said beam until a predetermined energy, and - a beam delivery module for delivering the accelerated beam from said linear accelerator toward the patient to treat a target volume with a radiation dose, The device further comprises intensity modulation means configured to modulate the distribution of the radiation dose in the target volume according to a predetermined pattern.The pattern is determined to match the dimensions of a target volume of at least about 50 cm3, and/or a target volume located at least about 5 cm deep in the tissue of the patient with said radiation dose,The radiation dose distributed is up to about 20 Gy delivered during an overall treatment time less than about 50 ms