Abstract:
An apparatus for delivering energy, and in particular laser energy, to a tissue includes a protective quartz cap that is secured to a laser delivery fiber by a crimp sleeve. The fiber may have a conical tip, and the quartz cap may be secured to the crimp sleeve by a layer of epoxy.

Description:
[0001]    This invention claims the benefit of U.S. Provisional Patent Application Ser. No. 61/129,518, filed Jul. 2, 2008. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to an improvement over the laser delivery arrangement described in U.S. patent application Ser. No. 11/714,785, filed Aug. 28, 2006, which was published on Mar. 21, 2007, as U.S. Published Patent Application No. 2007-1067937, and is incorporated herein by reference. 
         [0003]    The prior application discloses a laser delivery arrangement in which a Teflon™ introducer extends beyond the tip of the fiber and thereby prevents contact between the fiber tip and the wall of a blood vessel or other tissue being treated. The tip of the fiber is arranged to direct laser light in a radial direction so as to impinge on walls of the vessel. One example of a suitable fiber tip is a conical tip, which is also the type of tip illustrated herein, although it will be appreciated that other fiber tip configurations may be substituted for the illustrated fiber tip, and that the invention is not limited to a particular type of optical fiber. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
       [0004]    The improvement provided by the present invention is to replace the Teflon™ introducer with a quartz cap that is secured to the end of the fiber by a metal crimp sleeve. 
         [0005]    An example is illustrated in  FIG. 1 , which shows a fiber having a silicon core  1 , conical tip  2 , Teflon™ buffer  3 , and cladding layer  9 . The conical tip  3  directs laser energy supplied by the fiber in a generally radial direction though a quartz cap  4 , which is secured to the Teflon™ buffer  3  by a metal crimp sleeve  5  that is crimped to the buffer at one end  6 , and that is secured to the quartz cap at a second end  7  by a layer of epoxy  8 . The generally radial laser output is indicated by reference numeral  10 . 
         [0006]    In order to prevent thermal runaway to the quartz cap, a preferred method of using the arrangement illustrated in  FIG. 1  is to modulate the laser output during treatment of a tissue, for example by moving the fiber back and forth. 
         [0007]    The quartz cap arrangement described herein may advantageously be used with safety feedback arrangements of the type disclosed in copending U.S. patent application Ser. Nos. 11/510,691, filed Aug. 28, 2006 (Pub. No. 2007/0049911, Mar. 1, 2007); 11/714,785, filed Mar. 7, 2002 (Pub. No. 2007/0049911, Mar. 1, 2007); and 12/047,819, filed Mar. 13, 2008 (Pub. No. 2009/0062782, Mar. 5, 2009) to ensure that damage is minimized or prevented should overheating occur despite the modulation. The copending applications are incorporated herein by reference. 
         [0008]    Use with a safety feedback arrangement involves monitoring a temperature of the treatment site or radiation emitted during treatment in order to prevent damage due to overheating. As explained in the copending applications, different wavelengths of radiation may be monitored, including but not limited to visible light, and the monitoring may be carried out either by detectors at or near the treatment site or by transmitting the radiation back through the fiber. 
         [0009]    Having thus described preferred embodiments of the invention in sufficient detail to enable those skilled in the art to make and use the invention, it will nevertheless be appreciated that variations and modifications of the illustrated embodiment may be made without departing from the spirit of the invention. 
         [0010]    For example, different fibers may be substituted for the illustrated silicon core/Teflon™ buffer fiber, so long as the quartz cap can be secured thereto by a crimp sleeve. In addition, the crimp sleeve need not necessarily be made of metal, and the adhesive used to secure the quartz cap need not necessarily be epoxy. For example, adhesive materials other than epoxy may be substituted for epoxy layer  8 , and the metal crimp sleeve may alternatively be secured to the quartz cap by mechanical means, by welding, or by any other metal-to-quartz joining method or material. 
         [0011]    Still further, the crimp sleeve may be made of a material other than metal, transparent materials other than quartz may used in the cap, and the conical tip may be replaced by other tips such as the alternative tips disclosed in U.S. patent application Ser. No. 11/510,691, including orb-shaped, inverted cone-shaped, and angled tips, as well as tips with separate reflective structures such as the one shown in  FIG. 4E  of U.S. patent application Ser. No. 11/510,691. 
         [0012]    In addition, the arrangement of the preferred embodiments may be used with feedback arrangements other than those disclosed in U.S. patent application Ser. Nos. 11/510,691; 11/714,785; and 12/047,819, cited above, or without feedback, and in a wide variety of applications, including but not limited to endovascular applications. 
         [0013]    It is therefore intended that the invention not be limited by the above description or accompanying drawings, but that it be defined solely in accordance with the appended claims.