Abstract: Generally, the present invention provides a device for insertion into a body of a subject being treated to deliver localized x-ray radiation, and a method for use of such a device. The device includes an anode and a cathode, disposed within a vacuum housing. The device further includes a balloon coupled to and circumferentially surrounding the vacuum housing, and a fluid loop for circulating a cooling fluid proximate to the vacuum housing. A method for delivering localized x-ray radiation to an interior passage of a body is also described, including the steps of positioning an x-ray device at the passage to be treated and applying a high voltage to the x-ray producing unit to produce localized x-ray radiation.