A system and method are provided for imaging and treatment of tumorous tissue in a patient. In an embodiment, the system includes a radiation source for generating a radiation beam comprising high-energy photons with low energy distributions for high contrast imaging along with high energy distributions for efficient treatment dose delivery. The radiation source includes a charged particle accelerator that generates charged particles having energies of less than 6 megavolts (MV), a target to receive the charged particles and generate the high-energy photons of the radiation beam, and a collimator to emit the radiation beam. The system further includes an imaging device of high detective quantum efficiency to define a target region of the tumorous tissue in the patient using the radiation beam, and a controller to determine the shape and modulate the dose for treatment of the tumorous tissue based on the defined target region, using the radiation beam.
