Miniature X-ray source device
A 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 thereby. The X-ray source device at least includes a vacuum tube containing a cathode and an anode spaced apart at a distance from each other; an emitter for emitting free electrons from the cathode; an electric field generator for applying a high-voltage electric field between the cathode and the anode for accelerating the emitted free electrons towards the anode; and a getter material located in a high-voltage electric field free region in the vacuum tube. The vacuum tube is at least partly transparent to X-ray radiation emitted by the anode.
1. 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.
2. Miniature X-ray source device according to claim 1 , characterized in that said cathode is placed between said getter material and said anode.
3. Miniature X-ray source device according to claim 1 , characterized in that said cathode is at least partly covering said getter material.
4. Miniature X-ray source device according to claim 1 , characterized in that said cathode has an elongated shape with a polygonal cross-section and that said getter material is disposed within said cathode.
5. Miniature X-ray source device according to claim 4 , characterized in that said elongated shaped cathode has a circular or oval cross-section.
6. Miniature X-ray source device according to claim 4 , characterized in that said getter material is rod-shaped.
7. Miniature X-ray source device according to claim 1 , characterized in that said cathode is provided with at least one opening.
8. Miniature X-ray source device according to claim 7 , characterized in that said cathode is made from a grating material.
9. Miniature X-ray source device according to claim 1 , characterized in that said cathode is of a gated field emission type having a ferroelectric electron emitting material.
10. Miniature X-ray source device according to claim 9 , characterized in that said ferro-electric electron emitting material is positioned between a lower electrode and an upper electrode, both electrodes connected to a driving voltage.
11. Miniature X-ray source device according to claim 10 , characterized in that said upper electrode is constructed as an electrically conductive sheet provided with a large number of openings serving as emitting holes for the emitted free electrons.
12. Miniature X-ray source device according to claim 10 , characterized in that said upper electrode is constructed as at least one electrically conductive frame in which a large number disc shaped elements partly is fixed on ferro-electric electron emitting material.
13. Miniature X-ray source device according to claim 1 , characterized in that said cathode is of a cold cathode type formed from carbon nanotubes.
14. Miniature X-ray source device according to claim 13 , characterized in that said carbon nanotubes are aligned mono-wall nanotubes.
15. Miniature X-ray source device according to claim 13 , characterized in that said carbon nanotubes are aligned multi-wall nanotubes.
16. Miniature X-ray source device according to claim 13 , characterized in that said carbon nanotubes are randomized nanotubes.
17. Miniature X-ray source device according to claim 1 , characterized in that said vacuum tube comprises a distal end face, the inner surface of said distal end face also being provided with said anode material, and wherein a part of said electron emitting material of said cathode is facing said distal end face.
18. Miniature X-ray source device according to claim 17 , characterized in that said cathode is tubular shaped having a distal free end provided with electron emitting material directed towards said distal end face of said vacuum tube.
19. Miniature X-ray source device according to claim 17 , characterized in that said electron emitting surface of said cathode conforms to the inner surface of said vacuum tube being covered with said anode material.
20. Miniature X-ray source device according to claim 17 , characterized in that said distal end face of said vacuum tube and said distal free end of said cathode are semi-spherically shaped.
21. Miniature X-ray source device according to claim 17 , characterized in that said distal end face of said vacuum tube and said distal free end of said cathode are equally spaced apart from each other.
22. 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;
a getter material located in a high-voltage electric field free region in said vacuum tube; wherein
said vacuum tube being at least partly transparent to X-ray radiation emitted by said anode, characterized in that said cathode is arranged for shielding said getter material from said high-voltage electric field and characterized in that said cathode is supported by a hollow support tube with one end extending within the vacuum chamber and with the other end extending outside the vacuum chamber, which other end is subjected to a crimp-off operation for sealing the vacuum chamber.
23. Miniature X-ray source device according to claim 22 , characterized in that said hollow support tube is provided with multiple openings present in its circumferential surface.
24. Miniature X-ray source device according to claim 22 , characterized in that said crimped-off other end of the support tube serves as an electrical connection between the cathode and the emitting means for emitting free electrons from the cathode and/or the electric field means.