IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0701764
(1996-08-22)
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발명자
/ 주소 |
- Chornenky, Victor I.
- Forman, Michael R.
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출원인 / 주소 |
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대리인 / 주소 |
Ingrassia Fisher & Lorenz, P.C.
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인용정보 |
피인용 횟수 :
47 인용 특허 :
83 |
초록
▼
A catheter for emitting radiation is disclosed, comprising a catheter shaft and an x-ray unit attached to the distal end of the catheter shaft. The x-ray unit comprises an anode and a cathode coupled to an insulator to define a vacuum chamber. The cathode is preferably a field emission cathode of gr
A catheter for emitting radiation is disclosed, comprising a catheter shaft and an x-ray unit attached to the distal end of the catheter shaft. The x-ray unit comprises an anode and a cathode coupled to an insulator to define a vacuum chamber. The cathode is preferably a field emission cathode of graphite or graphite coated with titanium carbide, for example. The anode is preferably tungsten and the insulator is preferably pyrolytic boron nitride. The x-ray unit is preferably coupled to a voltage source through a coaxial cable. The anode is preferably a heavy metal such as tungsten. The cathode may also be a ferroelectric material. The x-ray unit can have a diameter less than about 4 mm and a length less than about 15 mm. Methods of use of the catheter are also disclosed. The catheter of the present invention can be used to irradiate the site of an angioplasty procedure to prevent restenosis. It can also be used to treat other conditions in any vessel, lumen or cavity of the body.
대표청구항
▼
1. An x-ray catheter comprising:a flexible catheter shaft for being advanced through lumens of the vascular system, the catheter shaft having a distal end;an x-ray unit coupled to the distal end, the x-ray unit comprising an anode, a cathode, an insulator having an external surface, and a conductive
1. An x-ray catheter comprising:a flexible catheter shaft for being advanced through lumens of the vascular system, the catheter shaft having a distal end;an x-ray unit coupled to the distal end, the x-ray unit comprising an anode, a cathode, an insulator having an external surface, and a conductive coating on the insulator, wherein the anode and cathode are coupled to the insulator to define a vacuum chamber. 2. The catheter of claim 1, wherein the anode comprises tungsten or platinum and the cathode comprises graphite. 3. The catheter of claim 1, wherein the cathode is a field emission cathode. 4. The catheter of claim 1, wherein the x-ray unit irradiates tissue at a rate of at least about 1 gray per minute. 5. The catheter of claim 1, wherein the insulator comprises pyrolytic boron nitride. 6. The catheter of claim 5, wherein the cathode and anode are coupled to a voltage generator. 7. The catheter of claim 6, wherein the catheter shaft comprises a coaxial cable coupling the anode and cathode to the voltage generator. 8. The catheter of claim 7, further comprising means for centering the x-ray unit within a lumen. 9. A catheter for emitting x-ray radiation in a vascular system, the catheter comprising:a flexible catheter shaft having a distal end;an x-ray unit coupled to the distal end, wherein the x-ray unit comprises an anode, a cathode, an insulator having an external surface, and a conductive coating on the external surface of the insulator, wherein the anode and cathode are coupled to the insulator to define a vacuum chamber and the conductive coating is electrically connected to the cathode. 10. The catheter of claim 9, wherein the insulator is chosen from the group consisting of beryllium oxide, aluminum oxide, or pyrolytic boron nitride. 11. The catheter of claim 9, wherein the cathode and the anode are coupled to a voltage generator. 12. The catheter of claim 9, further comprising a means for centering the x-ray unit within a lumen. 13. The catheter of claim 9, wherein the cathode is a ferroelectric material. 14. The catheter of claim 9, further comprising a guide wire lumen. 15. The catheter of claim 14, wherein the guide wire lumen extends partially through the catheter shaft. 16. The catheter of claim 9, further comprising a guide wire lumen extending through the catheter shaft. 17. The catheter of claim 9, wherein the anode is coupled to a wall of the insulator, wherein the wall is tapered towards the anode. 18. The catheter of claim 9, wherein the insulator and the cathode define an annular region between the cathode and the insulator, the annular region being screened by the conductive coating from an electrical field generated between the anode and the cathode. 19. The catheter of claim 9, wherein the cathode is a field emission cathode. 20. The catheter of claim 19, wherein the cathode is chosen from the group consisting of graphite, titanium carbide, carbides, metals, and graphite coated with titanium carbide. 21. The catheter of claim 19, wherein the cathode comprises silicon and the x-ray unit further comprises a grid proximate the cathode. 22. The catheter of claim 19, wherein the cathode comprises silicon needles. 23. The catheter of claim 9, wherein the catheter shaft comprises a coaxial cable, the coaxial cable having an outer conductor and a central conductor, the outer conductor being electrically connected to the conductive coating. 24. The catheter of claim 23, wherein the insulator has proximal and distal ends, wherein the anode is coupled to the central conductor of the coaxial cable at the proximal end of the insulator, and wherein the cathode is coupled to the distal end of the insulator. 25. The catheter of claim 23, wherein the insulator has a substantially tubular portion having proximal and distal ends, wherein the anode is coupled to the central conductor of the coaxial cable at the proximal end of the tubular portion, and wherein the cathode is coupled to the distal end of the tubular portion. 26. The catheter of claim 23, wherein:the coaxial cable comprises an outer conductor and a central conductor;the insulator has a tubular portion with proximal and distal ends, the coaxial cable being coupled to the proximal end, the anode being coupled to the proximal end and to the central conductor of the coaxial cable, and the cathode being coupled to the distal end;the catheter further comprises a conductive surface surrounding the tubular insulator, coupling the cathode to the outer conductor of the coaxial cable; andthe insulator and cathode define an annular region proximate the coupling between the cathode and the insulator, the annular region being screened from an electrical field generated between the anode and the cathode by the conductive surface and a portion of the cathode. 27. The catheter of claim 26, wherein the insulator comprises a wall depending from the proximal end of the tubular portion, the wall being angled toward the anode and the vacuum chamber. 28. The catheter of claim 9, wherein the x-ray unit has a diameter less than about 4 mm. 29. The catheter of claim 28, wherein the x-ray unit has a length less than about 15 mm. 30. The catheter of claim 23, wherein the x-ray unit has a diameter of 2.5 mm or less. 31. The catheter of claim 28, wherein the x-ray unit has a diameter of 1.25 mm or less. 32. The catheter of claim 28, wherein the x-ray unit has a diameter of about 1 mm. 33. The catheter of claim 32, wherein the x-ray unit has a length of about 7 mm.
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