Patent Abstract:
Methods and applicator apparatus are disclosed for brachytherapy treatment of tissue surrounding a cavity in a patient, particularly a resection cavity. In treatment regimes requiring recovery time between successive radiation treatments, applicators of the invention are retained under the skin, with the skin allowed to at least partially heal, and are re-accessed later for one or more subsequent treatments. To reduce patient discomfort an anesthetic agent can be infused through the applicator to patient tissue, for insertion, balloon inflation or removal of the applicator.

Full Description:
This application claims benefit from provisional application No. 60/851,687, filed Oct. 13, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention concerns balloon brachytherapy. 
     Balloon brachytherapy has been known since at least the 1950s, and involves placing a source of radiation within the body, generally near a tumor or within an excision site following removal of a tumor. The purpose or objective is to irradiate the tumor or the margins around the tumor excision cavity. The usual further objective is to provide dose levels of radiation to a target tissue volume surrounding the excision cavity which attain a therapeutic minimum, but below a level capable of producing significant normal-cell tissue necrosis. To accomplish this, a balloon applicator is employed into which the source of radiation is positioned. 
     Several improvements in applicator design are desirable. In anticipation of radiation therapy to follow complete or partial tumor excision, applicators can be placed within the excision cavity intraoperatively, i.e., during the surgical procedure and before the resection incision is closed. They may also be placed during a separate procedure at a later date when it has been decided to proceed with radiation therapy. Access to the excision cavity for radiation therapy may be through the original incision, or through a different incision purposely created for the applicator. A separate access site might be preferred if the anticipated dose distribution from the brachytherapy protocol, given the location of the excision cavity and proximity to sensitive tissue structures, might place those tissues at risk. When placed intraoperatively, the incision is closed around a sheath, which extends through and outside the skin of the patient. The applicator balloon is usually inflated when the incision is closed, and remains in place until radiation treatment is abandoned or the protocol completed, at which time the balloon is deflated and the applicator surgically removed. 
     Current or prior art balloon applicators include those described in J. H. Muller,  Radiotherapy of Bladder Cancer by Means of Rubber Balloons Filled In Situ with Solutions of a Radioactive Isotope  ( Co   60 ),  Cancer , September-October, 1955, pp 1035-1043;  The Clinical Use of Radioisotopes , B. V. A Low-Beer, Charles C. Thomas Publ., 1950;  A New Technique of Brachytherapy for Malignant Gliomas with Caesium  137:  A New Method Utilizing a New Afterloading System , R. D. Ashpole, et al, Clinical Oncology, vol. 2, 333-337, (1990); and U.S. Pat. No. 5,566,221. Radiation sources used for brachytherapy include small x-ray tubes as disclosed in U.S. Pat. Nos. 5,566,221, 6,319,188, and 6,987,835. Solid high-dose radiation isotope sources may be used, for example those sold by Varian Medical Systems, Inc., Palo Alto, Calif., and fluid isotope sources, for example a solution or slurry of radionuclides such as I-125 or Au-198. X-ray tubes offer both patient and therapist advantages including substantially reduced amounts of radiation and control of the radiation source. Radioisotope sources must be used inside bunkers lined with lead or other absorbers, with the patient being isolated in the bunker. Use of x-ray tubes is not subject to these restrictions. Unlike an x-ray tube, radioisotopes cannot be turned on and off, but rather emit radiation continuously. Those skilled in the art will appreciate that there are additional substantial differences between x-ray tube brachytherapy and radionuclide brachytherapy. 
     Radiation treatment often follows days after surgery, but preferably it follows weeks after surgery [See  Breast Cancer Research and Treatment , J. J. Jobson, et al (2006) 99:289294]and such protracted exposure of the surgical wound at the entry of the applicator sheath through the skin prior to commencing radiotherapy provides a substantial risk of infection that can compromise the resection cavity, and cause additional serious complications for the patient. Also, there can be significant discomfort if the applicator is placed intraoperatively and remains indwelling for an extended period and is perhaps inflated later prior to radiotherapy, or is placed and inflated later in a subsequent procedure, disturbing anatomy which is still sensitive from the resection. It would be beneficial to have an applicator and method which would minimize or eliminate this discomfort and infection risk, but otherwise offer the same or improved functionality and convenience as current applicators. Copending application Ser. No. 10/464,140, filed Jun. 18, 2003, discloses methods of intraoperative brachytherapy using electronic x-ray tubes, and the disclosure of that application is incorporated by reference herein. Copending application Ser. No. 11/811,069 discloses an everting gynecological discloses an everting gynecological applicator, and the disclosure of that applicator is also incorporated by reference herein. 
     SUMMARY OF THE INVENTION 
     This invention is directed to placing apparatus within a tumor resection cavity, preferably intraoperatively, such that the cavity may be easily reaccessed later for brachytherapy, but which allows the skin to be closed in the interim, thus facilitating healing. This method eliminates the need for apparatus passing through the skin between the resection procedure and initiation of radiation therapy. Such protruding apparatus can be easily bumped or disturbed, causing pain and perhaps infection, thereby impeding the healing process. 
     The apparatus of this invention comprises an expandable balloon which can be inflated within the excision cavity intraoperatively, after which the incision used to create or access the cavity is closed completely so healing can progress. At a later date when and if brachytherapy is to proceed, balloon access is reacquired, either by reopening the original incision or through a new incision at a preferable site. If such treatment is contra-indicated, the apparatus is used for deflation if necessary, and for removal of the apparatus entirely. 
     Advantageously the balloon apparatus further comprises an integral extension or a hollow sheath having length and forming a single longitudinal channel or a plurality of such channels which communicate with or extend into the balloon, and when accessed to commence radiation treatment, facilitate inflation or other functionality as outlined below. The channels can be fluid channels, such as for balloon inflation, infusion of anesthetic or therapeutic agents, cavity drainage, or they can accommodate instruments, inner sheaths or catheters, such as a catheter with a radiation source at its distal tip. When reaccessed by means of a new incision (or by reopening an old incision), the extension can be pulled outwardly to provide easy access to the balloon through the incision. 
     In a further embodiment, a housing at the proximal end of the sheath is affixed to the underside of the skin of the patient in a preferred location, preferably intraoperatively. The housing provides for self-sealing, percutaneous access to the sheath and balloon, but in other respects provides the same functionality as described above. 
     In yet another embodiment, the balloon is eliminated and a sheath provided which extends from under the skin well into the excision cavity. At commencement of radiotherapy, the skin over the closed end of the implanted sheath is incised, and the sheath withdrawn, but not so far as to lose communication with the excision cavity. The end of the sheath, if closed, is the cut off or otherwise removed, and a conventional balloon applicator (see  Brachytherapy,  6 (2007), 207-211, Smitt &amp; Kirby, “Dose—volume characteristics of a 50-kV electronic brachytherapy source for intracavitary accelerated partial breast irradiation) inserted into the implanted sheath such that the balloon is within the cavity, and the balloon inflated. The source catheter can then be inserted and brachytherapy begun. 
     In general, it is preferable that there be a portion of the sheath or balloon extension which protrudes outside of the patient&#39;s skin and which can be later further extended, gripped and/or manipulated. Such extensions can be corrugated, everted, and/or elastic such that they can be stretched outwardly beyond the surface of the patient&#39;s skin. 
     In the apparatus described above, it is preferable that a channel providing for drug or anesthetic delivery to, or seroma drainage from the cavity before commencing and/or during radiation therapy be incorporated in the apparatus of the invention. 
     From the description above, other embodiments will occur to those of skill in the art and are to be considered as within the scope of the invention. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic section view through tissue showing an inflated balloon placed in an excision cavity with the incision closed (incision not shown). 
         FIG. 2A  is a schematic section view through tissue with an inflated balloon shown in an incision cavity, the balloon having an everted extension, the proximal end of the eversion lying near the skin. 
         FIG. 2B  is a schematic section view through tissue with access having been made through to the extension and the extension extended such that it extends fully outwardly from the skin. 
         FIG. 2C  is a schematic section view through tissue with the extension re-everted around a source catheter which has been inserted into the proximal tip of the extension and advanced into the balloon. 
         FIG. 2D  is a similar section view through tissue with the extension re-everted around an inner sheath which has been inserted into the tip of the extension and advanced through the balloon and positioned within an optional centering pocket in the distal end of the balloon. A source catheter has been inserted into the inner sheath and advanced into the balloon. A balloon inflation tube with an in-line check valve has been provided alongside the balloon extension. 
         FIG. 3A  is a schematic section view through tissue with an inflated balloon bonded to the distal end of an outer sheath, the proximal end of the sheath lying under but near the skin, and the proximal end of the balloon everted to accommodate the length of the sheath. The proximal end of the sheath is closed. 
         FIG. 3B  shows the outer sheath of  FIG. 3A  having been accessed through the skin and extended outwardly from the skin, eliminating the balloon&#39;s eversion, with the end of the sheath removed. 
         FIG. 3C  shows the apparatus of  FIG. 3B  with an inner sheath inserted into the outer sheath and advanced fully into the balloon, thus engaging a central pocket at the distal end of the balloon and centering the inner sheath for source catheter positioning within the inner sheath. 
         FIG. 4A  is a schematic section view through tissue showing a balloon and sheath implanted, and further comprising a housing secured under the skin and in communication with the sheath and balloon. A syringe is shown injecting inflation medium into the balloon. 
         FIG. 4B  is a detail of a part of  FIG. 4A  schematically depicting a trap-door type one-way valve in the inflation channel of the apparatus. 
         FIG. 4C  is a section view showing self-sealing gel filler within the housing, with the central source channel being accessed by a hollow, split, percutaneous trocar-style sheath extension. 
         FIG. 4D  shows the apparatus of  FIG. 4C  with a source catheter inserted through the now fully seated split trocar sheath extension. 
         FIG. 5A  is a section view through tissue, schematically showing an alternate sheath embodiment having a convoluted or pleated shaft. The proximal end of the sheath is closed. 
         FIG. 5B  is a view of the embodiment of  FIG. 5A  with the proximal end of the convoluted sheath having been accessed through the skin and extended outwardly from the skin of the patient. 
         FIG. 6A  is a section view through tissue showing an inflated balloon with another embodiment of a sheath having an everted shaft positioned under the skin. 
         FIG. 6B  is a view of the apparatus of  FIG. 6A  with the sheath having been accessed and extended, with the eversion thus eliminated and the closed end removed. 
         FIG. 6C  is a view of the apparatus of  FIG. 6B  with a conventional hub attached to the proximal end of the sheath, and a source catheter inserted into the sheath and advanced into the balloon. A conventional seal has been provided within the hub to allow a suction channel to drain the excision cavity. 
         FIGS. 7A  and B are section views through body tissue which show an implanted sheath similar to that of  FIG. 5A , without a balloon, the sheath being later accessed and drawn outward ( FIG. 7B ) in a way similar to that shown in  FIG. 5B . 
         FIG. 8A  is a section view through body tissue showing a straight sheath implanted under the skin of the patient with its distal end well into the incision cavity following surgery. 
         FIG. 8B  is a section view of the sheath of  FIG. 8A  having been reaccessed through the skin of the patient and drawn outwards in much the same manner as the sheath of  FIG. 7B . 
         FIG. 9  is a section view through tissue showing an implanted sheath of  FIG. 7  or  8 , with its closed end removed and with an inner sheath comprising a balloon and hub inserted into the implanted sheath. A source catheter is shown within the inner sheath for purposes of irradiating the inside of the incision cavity. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The method of this invention comprises placing apparatus within or proximate a tumor resection cavity which facilitates easy reaccess to the cavity for brachytherapy. Such apparatus is preferably placed intraoperatively (but could be placed later in a separate procedure) and allows the skin to be closed pending a decision to proceed with, or to abandon brachytherapy. This method eliminates the need for apparatus passing through the skin for a protracted period and optionally provides for administration of therapeutic agents or anesthetic during subsequent apparatus manipulation or the brachytherapy treatment itself. The embodiments described below are used in conjunction with conventional brachytherapy apparatus. 
     The embodiments of the invention generally provide a convenient path for conventional brachytherapy apparatus to be inserted into the resection cavity some protracted time after the resection procedure itself. The procedure to reaccess the cavity begins with an incision (or percutaneous stick) to reach a portion of the implanted apparatus which is preferably near the skin of the patient. Next, an extension of the apparatus is established which protrudes through the skin at its proximal end, and leads into the resection cavity. Subsequent steps will depend on the invention embodiment chosen, but all lead to facilitating use of conventional brachytherapy methods and/or apparatus to complete the brachytherapy. 
       FIG. 1  depicts an apparatus  100  including a simple balloon  101  placed intraoperatively within the body and inflated in an excision cavity. A self-sealing patch  102  anywhere on the surface of the balloon suffices for inflation by a syringe. The patch can be relatively small compared to the balloon surface, or it can cover a significant portion of the surface. Self-sealing patch materials include various gel materials known in the art and silicone elastomers. Suitable balloon materials include polyurethanes and silicone rubbers. At one extreme, the material may be selected, and balloons may be designed, which are sufficiently elastic to conform to shape of the excision cavity. At the other extreme, materials and designs can be chosen which will substantially shape the cavity so that it conforms to a desired configuration, for example, so that it mimics the shape of the isodose surfaces which are generated by the brachytherapy source and apparatus in total and/or which correspond to the planned therapy. It is therefore also clear that balloon designs can be devised with properties between these extremes. As an example of such apparatus  100 , if the excision cavity is spherical, or can be forced into a spherical shape, an isotropic point source and spherical balloon filled with an absorber might advantageously be employed to produce a series of spherical isodose surfaces, each surface with decreasing dose at greater and greater radii from the source. 
       FIGS. 2A  and B depict a balloon  201  having a long radial extension  202 , shaped somewhat like a test tube. The length of the extension is greater than the distance between the excision cavity and the skin. The balloon can be partially inflated and the extension everted, for example by a rod (not shown), and with the rod removed, placed within the cavity positioned for later access through a cut down procedure or percutaneous stick at a desired location through the skin. See  FIG. 2A  for this configuration. Palpation may be adequate to locate the extension, or if desired, the skin can be marked for future access, for example by a tattoo dot  210 . Once positioned, the balloon can be fully inflated as described with respect to  FIG. 1  above so as to maintain the cavity until radiation brachytherapy is commenced. The incision is then closed over the brachytherapy balloon apparatus to begin the healing process. No parts of the apparatus protrude through the skin once the incision is closed. 
     When irradiation is to begin, the balloon extension  202  is accessed by percutaneous stick or incision, and the balloon extension withdrawn outwardly through the skin as shown in  FIG. 2B . Note that balloon pressure will tend to make the extension evert spontaneously. The end of the extension can then be manipulated to allow insertion of a radiation source catheter  203 . A preferred method is to insert a source catheter with a radiation source  204  at its tip into the extension such that the extension re-everts as the catheter is advanced into the balloon. Graduation marks  205  ( FIG. 2C ) on the catheter can be used to accurately position the depth of the catheter within the incision cavity. Such positioning can be confirmed by conventional imaging, and if desired, a clamp (not shown) can be used to secure the catheter within the protruding extension near its point of re-eversion to maintain the source position. 
     Rather than re-eversion as shown in  FIG. 2C , the extension may be cut off and a conventional hub with internal seal (not shown; similar to that of  FIG. 6C ) attached in an appropriate manner to the extension. It may be necessary to reestablish balloon inflation after the catheter is started into the hub and balloon extension. Graduation marks may be used to indicate position of the catheter within the balloon. With the hub seal to maintain inflation pressure integrity, a separate channel (as shown in  FIG. 2D , for example) can be provided alongside the balloon extension for inflation. 
     A particularly preferred embodiment is shown in  FIG. 2D . As shown, it may be convenient to provide an inner sheath  206  which in conjunction with the hub, seal and an optional distal balloon centering pocket  207 , facilitates accurate location of the source catheter. The inner sheath  206  serves to evert the extension  202  in the same manner as the catheter  203  in  FIG. 2C . The optional distal centering pocket  207  cooperates with the distal tip of the inner sheath  206  and facilitates proper positioning of the source  204 . Again, graduation marks  205  facilitate depth control of the catheter  203  relative to the proximal end of the inner sheath or the hub. Inflation of this embodiment is through a tube channel  208  adjacent to the balloon extension  202 , and incorporates an in-line check valve  209  (Halkey-Roberts Corporation, St. Petersburg, Fla.). 
     Balloons of the nature described in  FIGS. 1 and 2  can be fabricated by heat welding polymer sheet, for example polyurethane sheet (Deerfield Urethane, Inc., South Deerfield, Mass.) and subsequently pressure stretched at sufficient temperatures to form the desired shapes. Alternatively, they can be molded or formed from silicone rubber or other suitable polymers. Inflation channels such as that shown in  FIG. 2D  can be fabricated from tubing and components bonded together. 
       FIGS. 3A , B and C depict a balloon  301  bonded to a tubular outer sheath  302  having a closed proximal end  303 . The length of the sheath is such that when positioned under the skin in the desired location, the balloon must partially evert inwardly at  307  to accommodate the sheath length. Such a configuration is shown in  FIG. 3A . When accessed to commence brachytherapy, the sheath  302  is withdrawn outwardly from the skin and the end  303  is cut off or otherwise removed, as shown in  FIG. 3B .  FIG. 3C  shows the end of the sheath cut, and a conventional hub and seal (not shown, see  FIG. 6C  for a representative hub and seal) attached, for example by bonding, as described in connection with  FIG. 2  above. An inner sheath  304  is then inserted into the outer sheath and advanced into the balloon. Optionally, a centering pocket  305  may be provided in the distal end of the balloon to locate the tip of the inner sheath. Proper positioning can be verified by conventional imaging. Such provision facilitates accurate location of the radiation catheter  306  which is positioned in the inner sheath  304  for brachytherapy. Because of provision of a seal in the hub between the inner and outer sheaths, the hub may conveniently incorporate an inflation port for the balloon since a sealed annular lumen is provided between sheaths. Alternatively, use of an inner sheath  304  may be eliminated, and catheter  306  may be inserted directly into the outer sheath  302  and advanced into the balloon  301  for brachytherapy treatment. 
       FIG. 4A  shows a balloon  401  and sheath  402  with a receptacle or housing  403  at the proximal end of the sheath  402 . The sheath preferably is secured (for example by bonding) at both the proximal and distal ends of the balloon  401 , and to the distal side of the housing  403 . The sheath length is substantially fixed compared to the apparatus previously described with respect to that of  FIGS. 2 and 3 . The housing  403  is divided into two sections, a larger section  404  for the radiation source catheter (not shown), and a smaller for syringe access to a balloon inflation channel  405  positioned alongside the source catheter channel  406 . The housing may further comprise features which provide tactile feedback from outside of the patient&#39;s skin to assist locating and identifying individual channels, facilitating percutaneous access. Such features would include sized, positioned or shaped openings, or protrusions which can be felt by hand. 
     Both housing sections are filled with self sealing gel or silicone rubber  407  as described previously, and both are tapered or beveled such that a syringe  408  in the case of inflation, or a sheath extension for purposes of creating convenient source catheter access, can be guided into proper engagement with their respective channels percutaneously, or with the help of a cut-down procedure. Ring-like or other appendages or flanges with holes  411  are molded onto the exterior of the housing to facilitate suturing the housing to the skin. An inflation syringe  408  is shown inflating the balloon. Sutures are shown fastening the housing  403  to the patient&#39;s skin, an exemplary suture  410  from without the patient, and another suture  409  from within. Either approach may be used, and suturing may be through the entirety of the skin, or may be (from the inside) only through the subcutaneous layer. 
       FIG. 4B  shows a detail of the inflation channel  405  distal of the housing  403 . If the self sealing material is not strong enough to maintain inflation of the balloon, a valve  412  may be provided to maintain inflation. The valve illustrated in  FIG. 4B  is a conventional flapper type check valve on a molded live hinge, with syringe needle S shown holding it in an open position. 
       FIG. 4C  shows a detail of the housing  403  in section, with a female tapered bore  413  to accept a male taper  414  of a split-tip trocar style sheath extension  415 . The sheath extension  415  is shown entering the bore, to seat in the source catheter channel  406  behind the receptacle or housing  403 .  FIG. 4D  shows the trocar extension seated (if necessary, with removal of self-sealing material  407  to facilitate the seating) and the tip  416  spread open by the source catheter  417  advancing toward the balloon (not shown) through the source catheter channel  406  in the outer sheath  402 . 
       FIG. 5A  depicts an alternate sheath design with a convoluted or pleated extendable shaft  501 . With this design, the proximal end  502  of the sheath  501  may be grasped, extended and withdrawn free of the skin as shown in  FIG. 5B , and treated similarly to the sheath  302  of  FIG. 3 , including cutting off the end  502 . As an alternate to convolutions, the sheath can be elastomeric, and stretched to mimic the sheath of, for example,  FIGS. 2A-2D . 
       FIG. 6A  shows a balloon  601  and sheath  602  with an everted section  603  outside the balloon, such that the sheath section  603  folds over itself in coaxial configuration. The sheath  602  extends through the length of the balloon  601  and in this embodiment is fastened at its distal end (as by bonding for example) to the distal end of the balloon  601 . After a cutdown, this sheath can be withdrawn and everted such that the proximal end of the sheath extends free of the skin as shown in  FIG. 6B . This embodiment too can be fitted with a hub  604 , for example by threads  610 , and with an internal seal  605  for the source catheter  606 , as shown in  FIG. 6C . Alternately to cutting the end of sheath  602  to affix hub  604 , a threaded cap (not shown) can be provided which can be removed in order to fix the hub  604  to the sheath  602 . In this case, the annulus between the sheath  602  and the catheter  606  is utilized for suction from within the incision cavity for seroma and the like, as indicated by the arrows  607  at the distal end of the balloon  601 , and adjacent to the proximal end of the balloon. Suction applied at the arrow  608  will serve to evacuate the excision cavity. Features on the surface of the balloon  601  in accordance with the teachings of Ser. No. 11/639,495, as well as Ser. No. 10/683,885, both referenced above, can be used to provide distributed suction capability over the surface of the balloon  601 . Alternately, if the suction channel is reversed, again according to the teachings of Ser. No. 11/639,495, the channel can be used to infuse therapeutic or anesthetic agents into the cavity outside of the balloon  601 , or outside the shaft  602 . Anaesthetic can be administered to ease discomfort of the patient on removal of the applicator or on inflation of the balloon or re-inflation. If an inflation channel is desired, a second auxiliary port can be provided on the hub  604  communicating with a small lumen within the wall of the sheath (not shown) in a conventional manner. Arrows  609  indicate this channel. 
       FIG. 7A  shows schematically an implanted, convoluted sheath  701  without balloon positioned between incision cavity  704  and the skin of the patient. The sheath  701  has a closed proximal end  702 .  FIG. 7B  shows the sheath  701  of  FIG. 7A  having been reaccessed by cut down through the skin or other means, and drawn outward. Once proud of the skin, the closed end  702  is then removed, providing open access to the incision cavity for inserting of further brachytherapy apparatus into the cavity, preferably a conventional applicator and miniature x-ray source (now shown), and subsequent radiotherapy. A hub (not shown) may be used as in preceding embodiments if desired. 
       FIGS. 8A and 8B  schematically show a similar sheath  803  apparatus to that of  FIG. 7A , but rather than having a convoluted shaft, the sheath is straight and extends well into the cavity  804  when contained under the skin. After positioning the sheath  803 , the incision is closed in the manner described above, and the incision cavity allowed to collapse around the implanted sheath during the healing process.  FIG. 8B  shows the sheath  803  having been reaccessed and partially withdrawn above the skin such that the closed end  802  can be removed, all without losing access to the incision cavity  804 . Subsequently, radiotherapy commences in the manner described above in connection with  FIGS. 7A and 7B . 
       FIG. 9  depicts schematically an apparatus  900  comprising an implanted sheath structure  901  of  FIG. 7  or  8 , but in addition, an inner sheath  902  having a balloon  903  proximal of its distal end has been inserted into an incision cavity  904 . At the proximal end of the inner sheath  902 , a hub  905  is affixed, for example by bonding, and provides balloon inflation through a port  906  at the upper hub arm, and through a conventional port and lumen (neither shown) within the wall of the inner sheath  902 . The hub  905  also provides suction (see flow arrow  907 ) through the annulus between the sheaths  901  and  902  though a port  908  at the lower arm of the hub  905  and sheath ports  909  near the proximal end of the balloon  903  in the inner sheath  902 . A seal  912  at the proximal end of the sheath  901  provides pressure integrity for the suction channel. Reversing this fluid circuit will provide for infusion of therapeutic agents or anesthetic. 
     Within the inner sheath  902  and the hub  905  a source catheter  910  is inserted having a source  911  at its distal tip. 
     Several collateral features may be incorporated variously into the embodiments described above. The following are examples: 
     Radiation attenuating patches or balloon segments, or spacers, placed on or adjacent to balloons of the implanted apparatus, can be used locally to moderate radiation intensity, thus tailoring radiation output to variations in anatomy or prescription. Such radiation moderating devices are discussed in co-pending application Ser. No. 11/385,255, filed Mar. 20, 2006, the specification of which is incorporated herein in its entirety. 
     Embodiments with provision for drainage and agent infusion are described above. Exemplary apparatus and methods are described in co-pending application Ser. Nos. 11/639,495, filed Dec. 16, 2005, and 10/683,885, filed Oct. 10, 2003, the specifications of which are incorporated herein in its entirety. 
     The basic devices and methods of use described above, with or without the collateral features or techniques described, may be used in various combinations and permutations without departing from the scope of this invention. Each embodiment described preferably includes a portion of the applicator apparatus which, when reaccessed for radiotherapy, establishes an extension outside the skin that facilitates creation of an infection barrier for the duration of the prescribed therapy. The utility of these combinations will be apparent to those skilled in the art, as will variations to these embodiments

Technology Classification (CPC): 0