Patent ID: 7016471

Claim:
Miniature X-ray source device connected to a distal end of a guiding wire for insertion towards a desired location within an animal body for effecting radiation therapy, said X-ray source device at least comprising: a vacuum tube containing a cathode and an anode spaced apart at a distance from each other; emitting means for emitting free electrons from the cathode; electric field means for applying during use a high-voltage electric field between said cathode and said anode for accelerating said emitted free electrons towards said anode; and a getter material located in a high-voltage electric field free region in said vacuum tube and shielded from said high-voltage electric field by said cathode; wherein said vacuum tube being at least partly transparent to X-ray radiation emitted by said anode, characterized in that said cathode has a spatial construction surrounding said getter material, and wherein said getter material is supported by said cathode and electrically isolated therefrom.