A radiation therapy device includes an electron beam source (EBS) for generating an electron beam and a steering device for directing the electron beam. A target is disposed a predetermined distance from the EBS and is positioned to intercept the electron beam. The target element generates x-ray photons upon the impact of electrons with the target. A focusing lens is coupled to and spaced from the target by no more than 10 mm, and is positioned to receive x-ray photons generated by the target. The focusing lens focuses the x-ray photons to a focal point. The radiation therapy device can also include targets configured to generate x-ray beams for tomosynthesis. A method for performing radiation therapy is also disclosed.