Patent ID: 7200203

Claim:
A device for irradiating a portion of a body, said device comprising: (a) a rigid hollow radiation needle, said rigid hollow radiation needle having at least one rigid radiation conduit, said rigid radiation conduit having a first end and a second end, wherein said rigid radiation conduit is operable to pass primary x-rays from said first end to said second end, said primary x-rays being generated by an x-ray generator, said x-ray generator being external to said body, said x-ray generator being operably connected to said first end to pass said primary x-rays to said second end by means of said rigid radiation conduit, said rigid radiation conduit in said rigid hollow radiation needle having an internal diameter between one centimeter and 0.1 millimeters, said rigid hollow radiation needle having a length, said length being between 2 centimeters and 75 centimeters; (b) a fluorescent target connected to said second end of said rigid radiation conduit and positioned to absorb said primary x-rays passed to said second end to produce by fluorescence secondary x-rays for irradiating a predetermined portion of said body, said fluorescent target comprises at least one element having an atomic number that is one of 75–79 and 81, said fluorescent target having a shape, said shape having an essentially spherically-shaped surface, said surface absorbing a fraction of said primary x-rays whereby said fluorescent target is caused to fluoresce and to emit said secondary x-rays, said secondary x-rays and said primary x-rays being related by a peak energy index ratio between 0.01 and 1; and (c) an x-ray transmitting window positioned adjacent to said fluorescent target, said secondary x-rays exiting said rigid hollow radiation needle through said x-ray transmitting window, said secondary x-rays irradiating a volume, said volume conforming to a predetermined portion of a target tissue within said body, said volume being between one tenth of a cubic millimeter and 115 cubic centimeters whereby said tissue is therapeutically irradiated by said secondary x-rays.