Method of manufacturing a miniature X-ray device

• US 20030133541A1
• Filed: 02/05/2003
• Published: 07/17/2003
• Est. Priority Date: 01/17/2001
• Status: Active Grant

• Current Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Inventors: Jaafar, Ali, Chornenky, Victor I., Park, Eunsung, Kerslick, Graham S., Gailloux, Mark
• Granted Patent: US 7,086,577 B2
• Time in Patent Office: Days
• US Class Current: 378/119
• CPC Class Codes: A61N 5/1001 using radiation sources introduced into or applied onto the body; brachytherapy
• CPC Class Codes: H01J 2235/164 Small cross-section, e.g. for entering in a body cavity
• CPC Class Codes: H01J 35/32 Tubes wherein the X-rays are produced at or near the end of the tube or a part thereof which tube or part has a small cross-section to facilitate introduction into a small hole or cavity

Abstract

An emitter for a miniature X-ray apparatus comprises an insulating shell, an anode, and a cathode. The insulating shell includes a conical brazing surface, brazed to a conical brazing surface on the anode. The braze consists of a pure titanium layer and a pure tin layer. During brazing, the pure metals react and bond to the insulating shell and create a titanium-tin alloy between the pure layers. Pure tin is sputtered from tin sputter target onto the exposed brazing surfaces of the cathode cap and the anode. The insulating shell is placed in a vacuum chamber of deposition applicator, which deposits an active metal onto the shell brazing surface. In a brazing oven, the anode is placed within insulating shell such that the anode conical brazing surface and the shell conical brazing surface are contacting and aligned with each other. During brazing, the cathode is brought into contact with the insulating shell. The sealed emitters are placed in a sputtering machine'"'"'s vacuum chamber. A metal is sputtered from a sputtering target to form a metal layer on the exterior of insulating shell.

Claims

1. A device to be introduced via an introducer or trocar for delivery of X-ray radiation, comprising:

an insulating shell having a brazing surface;

a cathode housed within said insulating shell;

an anode housed within said insulating shell and having a brazing surface; and

a conical seal, said conical seal bonding said brazing surface of said anode to said brazing surface of said insulating shell.

2. The device of claim 1, wherein said insulating shell is crystalline quartz.

3. The device of claim 1, wherein said insulating shell includes an outer metal coating.

4. The device of claim 3, wherein said outer metal coating is silver.

5. The device of claim 1, wherein said conical seal comprises a layer of pure tin located on said brazing surface of said anode and a layer of pure titanium located on said brazing surface of said insulating shell.

6. The device of claim 5, wherein said layer of pure titanium is applied onto said brazing surface of said insulating shell by a high energy deposition process.

7. The device of claim 5, wherein said layer of pure tin is sputtered onto said brazing surface of said anode.

8. The device of claim 1, wherein said conical seal is a braze of tin and titanium.

9. The device of claim 8, wherein the braze occurs at a temperature between 500 and 750°

C.

10. An emitter for an intravascular irradiation catheter, comprising:

an insulating shell of crystalline quartz;

a cathode housed in said insulating shell; and

an anode conically bonded to an interior surface of said insulating shell.

11. The emitter of claim 10, wherein said bond comprises a layer of pure tin located on a brazing surface of said anode and a layer of pure titanium located on a brazing surface of said insulating shell.

12. The emitter of claim 11, wherein said bond is comprised of titanium plated onto said insulating shell by cathodic arc deposition.

13. The emitter of claim 12, wherein said bond is further comprised of tin sputtered onto said anode.

14. The emitter of claim 10, wherein said anode is conically bonded by a braze of tin and titanium.

15. The emitter of claim 14, wherein the braze occurs at a temperature between 500 and 750°

C.

16. The emitter of claim 10, wherein said insulating shell includes an outer metal coating.

17. The emitter of claim 16, wherein said metal coating is silver.

18. A method for brazing a nonmetal material, comprising:

applying a pure tin layer onto a brazing surface of a first material;

applying a pure titanium layer onto a brazing surface of a second material;

aligning said brazing surface of said first material with said brazing surface of said second material, such that said tin layer and said titanium layer are in contact; and

heating said tin layer and said titanium layer, wherein said tin layer liquifies and bonds with at least a portion of said titanium layer.

19. The method of claim 18, wherein said tin layer is applied by sputtering.

20. The method of claim 18, wherein said titanium layer is applied by cathodic arc ion deposition.

21. The method of claim 20, wherein said titanium layer is 3-7 microns thick.

22. The method of claim 18, wherein said heating is performed in a vacuum environment of 10⁻

6 torr.

23. The method of claim 18, wherein said heating step activates getters.

24. The method of claim 18, wherein said bonding occurs between temperatures of 500-750°

C.

25. The method of claim 18, further comprising applying a metal coating onto the outer surface of the shell.

26. The method of claim 25, wherein said metal is silver and is 1-5 microns thick.

27. A method for brazing an emitter for delivery of X-ray radiation, comprising:

applying a first metal onto a conical surface of an anode;

applying a second metal onto a conical surface of an insulating shell, wherein said insulating shell has first end and a second end;

thermally bonding said first metal on said conical area of said anode into said insulating shell, directly to said second metal on said conical area of said insulating shell; and

bonding a cathode within the second end of said insulating shell.

28. The method of claim 27, wherein said first metal is applied by sputtering.

29. The method of claim 27, wherein said second metal is applied by cathodic arc deposition.

30. The method of claim 27, wherein said first metal is tin and said second metal is titanium.

31. The method of claim 30, wherein said titanium is 3-7 microns thick.

32. The method of claim 27, further comprising, placing said anode, said cathode, and said insulating shell into a brazing oven and vacuuming to 10⁻

6 torr.

33. The method of claim 32, wherein the oven is heated to activate getters.

34. The method of claim 32, wherein said thermal bonding occurs between temperatures of 500 and 750°

C.

35. The method of claim 27, further comprising applying a metal onto the outer surface of said shell.

36. The method of claim 35, wherein said metal is silver and is 1-5 microns thick.