Multi layer radiation delivery balloon

• US 20030163017A1
• Filed: 10/01/2002
• Published: 08/28/2003
• Est. Priority Date: 02/19/1998
• Status: Abandoned Application

• Current Assignee: Brett A. Trauthen, Lisa A. Tam
• Original Assignee: Brett A. Trauthen, Lisa A. Tam
• Inventors: Trauthen, Brett A., Tam, Lisa A.
• Application Number:
  US10/262,639
• Publication Number:
  US 20030163017A1
• Time in Patent Office: Days
• US Class Current: 600/3
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61K 51/1279 Plasters, bandages, dressings, patches or adhesives
• CPC Class Codes: A61K 51/1282 Devices used in vivo and carrying the radioactive therapeutic or diagnostic agent, therapeutic or in vivo diagnostic kits, stents
• CPC Class Codes: A61K 9/1641 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poloxamers
• CPC Class Codes: A61M 2025/1075 having a balloon composed of several layers, e.g. by coating or embedding
• CPC Class Codes: A61N 2005/1004 having expandable radiation sources
• CPC Class Codes: A61N 2005/1005 with asymmetrical radiation pattern
• CPC Class Codes: A61N 5/1002 Intraluminal radiation therapy
• CPC Class Codes: G03C 5/02 Sensitometric processes, e.g. determining sensitivity, colour sensitivity, gradation, graininess, density; Making sensitometric wedges
• CPC Class Codes: G21G 4/06 characterised by constructional features
• CPC Class Codes: Y10S 977/949 Radiation emitter using nanostructure

Abstract

Disclosed is a sealed radiation source, which may be used to deliver a radioactive dose to a site in a body lumen. The source comprises a thin flexible substrate, and a layer of radioisotope attached thereto. The source may further comprise additional layers such as one or more tie layers disposed between the substrate and the radioisotope layer and one or more outer coating layers. In one embodiment, the source is wrapped around an inflatable balloon. Inflation of the balloon at a treatment site positions the source directly adjacent to the vessel wall, and allows irradiation of the site following or simultaneously with a balloon angioplasty, stent implantation, or stent sizing procedure.

Claims

1. A multilayer radiation delivery source, comprising:

a first bonding layer, having a first side;

a second bonding layer, having a second side which faces toward the first side; and

an isotope layer in between the first side and the second side;

wherein the first side and the second side are secured together through the isotope layer to produce a multilayer radiation delivery source.

2. The source of claim 1, wherein said isotope is a gamma emitting isotope or a beta emitting isotope.

3. The source of claim 1, wherein the isotope is selected from the group consisting of P-32, I-125, Pd-103, W/Re-188, As-73, Gd-153, and combinations thereof.

4. The source of claim 1, further comprising a structural layer on at least one of the first and second bonding layers.

5. The source of claim 1, wherein the source comprises a sheet having a total thickness of no more than about 0.003 inches.

6. The source of claim 1, wherein the source comprises a tube having a total wall thickness of no more than about 0.003 inches.

7. The source of claim 1, further comprising a first structural layer on the first bonding layer and a second structural layer on the second bonding layer.

8. The source of claim 7, wherein the first and second bonding layers are fused together to provide a continuous seal from proximally of to distally of the isotope layer.

9. The source of claim 7, further comprising a coating layer on the isotope layer.

10. The source of claim 9, wherein the coating layer comprises a material selected from the group consisting of cyanoacrylates, acrylics, acrylates, acrylic acid, urethanes, polybutyl vinyl chloride, polyvinylidene chloride, polyethylene and combinations thereof.

11. The source of claim 7, wherein at least one of the first and second structural layers comprises a material selected from the group consisting of polyamide, polyethylene, polyester, polyethylene terephthalate, polyvinyl chloride and combinations thereof.

12. The source of claim 11, wherein the first and second bonding layers comprise ethylene methyl acrylate.

13. The source of claim 12, wherein the first and second structural layers comprise polyethylene.

14. The source of claim 12, wherein the first and second bonding layers are sufficiently adhered together that they can not be manually delaminated from each other without tearing.

15. The source of claim 12, comprising at least one co-extrusion of EMA and PE, or EMA and polyurethane.

16. A radiation delivery balloon catheter, comprising:

an elongate flexible tubular body, having a proximal end and a distal end;

an inflatable balloon on the tubular body near the distal end thereof, said balloon in fluid communication with an inflation lumen extending axially through the tubular body;

a balloon bonding surface carried by the outer surface of the balloon;

a radiation source on the balloon bonding surface; and

an encapsulant surrounding the radiation source, the encapsulant having at least an encapsulant bonding surface on its radially inwardly facing surface for fusing with the balloon bonding surface at least proximally and distally of the radiation source.

17. A radiation delivery balloon catheter as in claim 16, wherein the balloon bonding surface comprises ethylene methyl acrylate.

18. A radiation delivery balloon catheter as in claim 17, wherein the encapsulant bonding surface comprises ethylene methyl acrylate.

19. A radiation delivery balloon catheter as in claim 16, wherein the encapsulant comprises an outer polyethylene layer and an inner ethylene methyl acrylate layer.

20. A radiation delivery balloon catheter as in claim 16, wherein all bonding surfaces comprise the same material.

21. A radiation delivery balloon catheter as in claim 16, wherein the radiation source comprises a metal salt or oxide, and at least one isotope.

22. A radiation delivery balloon catheter as in claim 21 wherein the source further comprises a tie layer for binding with an isotope.

23. A radiation delivery balloon catheter as in claim 16, wherein the source comprises at least one source bonding layer to permit a continuous bond between the source and at least one of the encapsulent and the balloon bonding surface from proximally of the source to distally of the source.

24. A radiation delivery balloon catheter as in claim 16, further comprising a guide wire lumen extending axially throughout at least a distal portion of the tubular body.

25. A radiation delivery balloon catheter as in claim 24 further comprising a proximal guide wire access port on the tubular body, positioned within about 35 cm of the distal end of the tubular body.

26. A radiation delivery balloon catheter as in claim 16, further comprising a perfusion conduit extending through the tubular body from a proximal side of the inflatable balloon to a distal side of the inflatable balloon, at least a first perfusion port on the tubular body on the proximal side of the balloon and at least a second perfusion port on the distal side of the balloon.

27. A radiation delivery balloon catheter as in claim 26, wherein the perfusion conduit comprises a distal portion of a guidewire lumen.

28. A method of treating a site within a vessel, comprising the steps of:

identifying a site in a vessel to be treated;

providing a radiation delivery catheter having an expandable balloon with a thin film radiation source thereon, said thin film comprising a substrate layer having an isotope thereon, said isotope encapsulated by an outer encapsulant layer fused to the substrate throughout the length of the source;

positioning the balloon within the treatment site;

inflating the balloon within the treatment site;

delivering a dose of radiation from the delivery balloon to the treatment site; and

thereafter deflating the balloon and removing the balloon from the treatment site.

29. The method of claim 28, wherein said catheter has an isotope loss of no more than 5 nCi throughout the period between the positioning step and the removing step.

30. A method of treating a site within a vessel as in claim 28, wherein said source comprises a metal salt or a metal oxide, and at least one isotope.

31. A method of treating a site within a vessel as in claim 28, wherein said site comprises a previously implanted prosthesis, and the positioning the balloon step comprises positioning the balloon at least partially within the prosthesis.

32. A method of treating a site within a vessel as in claim 31, wherein the prosthesis comprises a stent.

33. A method of treating a site within a vessel as in claim 31, wherein the prosthesis comprises a graft.

34. A method of treating a site within a vessel as in claim 28, wherein the radiation delivery catheter further comprises an expandable stent on the balloon, and wherein the inflating the balloon step comprises inflating the balloon within the treatment site to implant the stent at the treatment site and simultaneously delivering radiation from the thin film into the vessel wall.

35. A method of treating a site within a vessel as in claim 28, further comprising the step of perfusing blood from a first side of the balloon to a second side of the balloon during the delivering a dose of radiation step.

36. A method of simultaneously performing balloon dilatation of a stenosis in a body lumen and delivering radiation to the body lumen, comprising the steps of:

identifying a stenosis in a body lumen;

providing a treatment catheter having an elongate flexible tubular body with an inflatable balloon near the distal end thereof, a cylindrical thin film radiation delivery layer on the balloon, an encapsulant layer over the radiation delivery layer, a continuous seal between the encapsulant, the delivery layer and the balloon along at least the length of the radiation delivery layer;

transluminally advancing the balloon through the lumen;

positioning the balloon within the stenosis;

inflating the balloon to radially expand the lumen in the area of the stenosis; and

simultaneously delivering radiation from the thin film into the lumen wall.

37. A method of simultaneously performing balloon dilatation of a stenosis in a body lumen, delivering a stent, and delivering radiation to the body lumen, comprising the steps of:

identifying a stenosis in a vessel;

providing a treatment catheter having an elongate flexible tubular body with an inflatable balloon carrying an expandable stent near the distal end thereof, and a cylindrical thin film radiation delivery layer on the balloon, an encapsulant layer over the radiation delivery layer, a continuous seal between the encapsulant, the delivery layer and the balloon along at least the length of the radiation delivery layer;

transluminally advancing the balloon through the vessel;

positioning the balloon within the stenosis;

inflating the balloon to radially expand the vessel in the area of the stenosis; and

simultaneously expand and deliver the stent; and

delivering radiation from the thin film to the vessel wall.

38. A method of manufacturing a sealed source radiation delivery balloon catheter, comprising the steps of:

extruding a tube for producing a balloon, having a bonding layer on a radially outwardly facing surface thereof;

positioning an annular radiation delivery source on the balloon bonding layer;

extruding a tubular encapsulant having a sealing layer on a radially inwardly directed surface thereof;

positioning the encapsulant concentrically around the radiation source and the balloon to produce a balloon-source-encapsulant stack;

exposing the balloon-source-encapsulant stack to elevated temperature to bond at least one of the balloon and the encapsulant to the source thereby producing a sealed source.

39. The method of claim 38, wherein the encapsulant is coextruded to have a radially inwardly directed sealing surface and an outer structural surface.

40. The method of claim 39, wherein the structural surface comprises polyethylene and the sealing surface comprises ethylene methyl acrylate.

41. The method of claim 38, wherein the exposing step fuses the encapsulent to the balloon through the source.

42. The method of claim 38, further comprising the step of inflating the balloon prior to the exposing step.

43. The method of claim 38, wherein the extruding a tube step comprises coextruding a tube having at least an inner structural layer and an outer bonding layer.

44. The method of claim 38, wherein the radiation delivery source comprises a bonding layer and an isotope layer.

45. The method of claim 44, wherein the isotope layer comprises a metal salt or oxide, and at least one isotope.

46. The method of claim 45, wherein the isotope layer further comprises a tie layer.

47. The method of claim 44, wherein the radiation delivery source further comprises a structural surface on the bonding layer.

48. The method of claim 44, wherein the radiation delivery source further comprises a coating layer on the isotope layer.

49. A multilayer radiation delivery source, comprising:

a first portion comprising a first support layer having a first bonding layer thereon;

a second portion comprising a second support layer having a second bonding layer thereon; and

a third portion comprising an isotope;

wherein the third portion lies between the first and second bonding layers and the first and second bonding layers begin to melt at a different temperature than the first and second support layers.

50. The multilayer radiation delivery source of claim 49, wherein the first and second bonding layers begin to melt at a lower temperature than the first and second support layers.