Abstract:
The disclosure describes a device for asymmetrical irradiation of a body cavity or site, such as after removal of tissue, e.g. biopsy or lumpectomy. The device includes an elongated tubular shaft having an inner lumen and a tubular wall with a plurality of lumens extending within the wall which are configured for receiving a radiation source. The distal portion of the tubular shaft is cut into a plurality of longitudinally separated wall segments with a lumen extending within at least one of the wall segments. A support member is positioned within the separated wall segments to support and position the wall segments in a desired configuration for brachytherapy. An expandable member such as an inflatable balloon is mounted on the distal shaft portion about the separated wall segments wall which when inflated secures the distal shaft portion within a desired intracorporeal site for brachytherapy treatment.

Description:
RELATED APPLICATIONS 
       [0001]    This application is related to provisional application Ser. No. 61/062,179, filed on Jan. 24, 2008, which is incorporated herein in its entirety and which is relied upon for priority. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention generally relates to devices and methods for treating tissue surrounding a body cavity, such as a site from which cancerous, pre-cancerous, or other tissue has been removed. 
       BACKGROUND OF THE INVENTION 
       [0003]    In diagnosing and treating certain medical conditions, it is often desirable to perform a biopsy, in which a specimen or sample of tissue is removed for pathological examination, tests and analysis. A biopsy typically results in a biopsy cavity occupying the space formerly occupied by the tissue that was removed. As is known, obtaining a tissue sample by biopsy and the subsequent examination are typically employed in the diagnosis of cancers and other malignant tumors, or to confirm that a suspected lesion or tumor is not malignant. Treatment of cancers identified by biopsy may include subsequent removal of tissue surrounding the biopsy site, leaving an enlarged cavity in the patient&#39;s body. Cancerous tissue is often treated by application of radiation, by chemotherapy, or by thermal treatment (e.g., local heating, cryogenic therapy, and other treatments to heat, cool, or freeze tissue). 
         [0004]    Cancer treatment may be directed to a natural cavity, or to a cavity in a patient&#39;s body from which tissue has been removed, typically following removal of cancerous tissue during a biopsy or surgical procedure. For example, U.S. Pat. No. 6,923,754 to Lubock and U.S. patent application Ser. No. 10/849,410 to Lubock, the disclosures of which are all hereby incorporated by reference in their entireties, describe devices for implantation into a cavity resulting from the removal of cancerous tissue which can be used to deliver cancer treatments to surrounding tissue. One form of radiation treatment used to treat cancer near a body cavity remaining following removal of tissue is “brachytherapy” in which a source of radiation is placed near to the site to be treated. 
         [0005]    Lubock above describes implantable devices for treating tissue surrounding a cavity left by surgical removal of cancerous or other tissue that includes an inflatable balloon constructed for placement in the cavity. Such devices may be used to apply one or more of radiation therapy, chemotherapy, and thermal therapy to the tissue surrounding the cavity from which the tissue was removed. The device may be configured to receive a solid or a liquid radiation source or both. Radiation treatment is applied to tissue adjacent the balloon of the device by placing radioactive material such as radioactive “seeds” in a delivery lumen within a distal treatment location. Such treatments may be repeated if desired. While the radiation source is typically a solid radiation source, a radiation source such as a miniature or micro-miniature x-ray tube may also be used (e.g. U.S. Pat. No. 6,319,188). The x-ray tubes are small, flexible and are believed to be maneuverable enough to reach the desired treatment location within a patient&#39;s body. The radiation source is to be removed following each treatment session, or remains in place as long as the balloon remains within the body cavity. These inflatable treatment delivery devices and systems are useful to treat cancer in tissue adjacent a body cavity. 
         [0006]    However, radiation, chemotherapy, thermal treatment, and other cancer treatments often have deleterious effects on healthy tissue in addition to the desired effects on cancerous tissue. In such treatments, care must be taken to direct the maximum treatment effects to diseased tissue while minimizing its delivery or effects on healthy tissue. For example, radiation treatment may be most effective when only the portion of tissue requiring treatment receives the radiation and where surrounding healthy tissue is unaffected. Tissue cavities typically are not uniform or regular in their sizes and shapes, so that differences in dosages applied to different regions of surrounding tissue, including “hot spots” and regions of relatively low dosage, often result from radiation treatment. 
         [0007]    Features of a treatment delivery device for treating tissue adjacent a body cavity, included in the Contura™ multilumen balloon catheter, have been disclosed in U.S. Pat. No. 6,923,754. This patent describes applying a partial-vacuum or suction to bring tissue towards an inflated balloon around a radiation source and allows for uniform application of radiation to tissue surrounding a body cavity. Additional features are described in copending applications Ser. No. 11/593,784 and Ser. No. 11/593,789 relating to multilumen catheters which allow a greater degree of flexibility in asymmetric radiation source placement within the body cavity. However, some of these catheter constructions are complex and difficult to manufacture. 
       SUMMARY OF THE INVENTION 
       [0008]    This invention is generally directed to a balloon catheter for treating a patient&#39;s body cavity or other intracorporeal site (hereinafter collectively referred to as a body cavity) and methods for such treatments. The invention is particularly suitable for treating tissue adjacent to a body cavity formed by the removal of tissue such as from a patient&#39;s breast in a lumpectomy. 
         [0009]    More specifically, a device embodying features of the invention has an elongated shaft, a distal end, a distal shaft portion which has a treatment location and an inner lumen extending to the distal shaft portion. The elongated shaft has a shaft wall which at least in part defines an inner lumen and which has a plurality of lumens within the wall. The shaft wall in the distal shaft portion has a plurality of separated longitudinal wall segments having at least one lumen extending therein. A support member preferably extends within the distal shaft portion to support the separated longitudinal wall segments and preferably has a plurality of recesses configured to receive and support the separated longitudinal wall segments. The recesses of the support member preferably place the wall segments into a convex arcuate configuration away from a central longitudinal axis. The support member preferably has an inner lumen in fluid communication with the inner lumen defined by the shaft wall and preferably continues and is in fluid communication with the inner lumen of a tubular member within the inner lumen of the elongated shaft. The distal ends of the separated longitudinal wall segments are secured to the distal end of the support member or a distal tip of the elongated shaft with the separated wall segments in convex arcuate configurations away from the longitudinal axis. A distal tip at the distal end of the shaft preferably closes off the inner lumen of the support member and one or more of the lumens which extend within the wall segments. 
         [0010]    The inner lumen of the elongated shaft within the treatment location and at least one of the lumens extending within the separated longitudinal wall segments are configured to receive a radiation source so as to treat tissue adjacent to the distal shaft portion. The lumens may be coated with a lubricous material or lined with a tubular member with an inner lumen having suitable lubricous properties (or a lubricous material thereon) to allow radiation sources to be readily advanced therein. 
         [0011]    Preferably, the catheter has an enlarged or enlargeable cavity filling member at the treatment location, such as an inflatable which at least in part fills the body cavity. The cavity filling member is mounted onto the distal shaft portion surrounding the separated longitudinal wall segments so that when expanded will hold tissue lining the body cavity in a desired configuration. The proximal end of the balloon is secured proximal to the arcuate separated longitudinal segments and the distal end is secured to the distal ends of the separated longitudinal wall segments, the distal tip or both. 
         [0012]    The distal tip of the catheter preferably has proximally extending plugs members to close off the lumens within the wall segments and preferably, the inner lumen of the support member. 
         [0013]    One or more of the lumens in the shaft wall may be used to deliver inflation fluid to the interior of a balloon surrounding the distal shaft portion. One or more of the lumens in the shaft wall may be connected to a vacuum source to provide a vacuum to regions surrounding the distal shaft portion proximal and/or distal to the balloon through one or more vacuum ports therein, such as described in U.S. Pat. No. 6,923,754 and co-pending application Ser. No. 10/849,410 filed on May 19, 2004, both of which are assigned to the SenoRx, Inc., present assignee. Application of a vacuum within the inner lumen aspirates fluid in the cavity through one or more vacuum ports and the vacuum within the body cavity pulls tissue defining the cavity onto the exterior of the cavity filling member deployed within the cavity. 
         [0014]    The arcuate configuration of the longitudinal wall segments allows for asymmetric deployment of radiation sources within the body cavity as described in co-pending applications Ser. No. 11/593,784, and Ser. No. 11/593,789, both filed on Nov. 6, 2006, so as to be closer to a first portion of tissue surrounding the cavity than a second portion of tissue surrounding the cavity opposite the first tissue portion. This facilitates the radiation source to be offset or capable of being offset within the body cavity so that tissue of one portion of the cavity closer to the source receives more intense radiation treatment and tissue of the second portion further from the source receives less radiation. 
         [0015]    The elongated shaft may also have one or more radiation shielding components designed to reduce or minimize damaging irradiation of healthy tissue surrounding the body cavity while treating nearby areas having diseased tissue with radiation emitted from the radiation source. The radiation shielding components include one or more radiation shields disposed about a delivery shaft containing the radiation source. Suitable radiation shielding components are describe in co-pending applications Ser. Nos. 11/593,678 and 11/593,952, both filed on Nov. 6, 2006, both assigned to SenoRx, Inc. the present assignee. 
         [0016]    A method for treating a body cavity or other intracorporeal site of a patient includes delivering a treatment agent such as a radiation source to a body cavity to treat the desired tissue while minimizing damaging irradiation of healthy tissues. More specifically, a method for treating a body cavity or intracorporeal site includes providing a device having an elongate shaft with a proximal end, a distal end, and a treatment location in a distal portion of the shaft. The method further includes providing a radiation source configured to be deposited in the treatment location and a radiation shielding component partially encircling the treatment location which is configured to control at least in part the emission of radiation emitted from the treatment location. The device is advanced within the patient until the treatment location of the device is deployed within the body cavity or site and the radiation source is positioned within the treatment location. The radiation shielding component is positioned to shield portions of the body cavity from radiation emitted from the radiation source. 
         [0017]    A patient&#39;s skin is susceptible to damage from radiation delivered by isotopes (e.g. seeds) or x-ray catheters in a lumen of a radiation balloon catheter if the radiation source is too close to the skin. Generally, radiation treatments using a radiation balloon catheter is usually not performed on patients where the body cavity (e.g. from a lumpectomy) is less than 5 mm, sometimes less than 7 mm from the patient&#39;s skin. Additionally, over inflation of the balloon can thin and stretch the skin. The application of a vacuum to the body cavity can help by pulling the tissue to the balloon and increased cavity to skin surface distances would result. However, in some instances it would still be too thin to treat. The number of potential patient&#39;s which are suitable candidates for treatments with the present device is significantly increased due to reducing the potential for skin tissue damage. 
         [0018]    The surface (inside or outside) of the balloon or within the balloon wall may be provided with indicator marks for location or orientation detection during the procedures. For example, dots or lines to help place balloon in appropriate position under CT, x-ray or fluoroscopy. The indicator marks may be radiopaque. Alternatively, or additionally, ultrasound indicators or MRI and direct visual indicators could be incorporated. The indicator marks may extend along the catheter shaft to help with placement of the catheter device during the treatment procedure and the orientation of the off-set lumen and shield. 
         [0019]    One attractive additional feature for brachytherapy for breast lumpectomy sites is to provide heat to the tissue lining of the cavity either simultaneously with or sequentially to (before or after) irradiation. Suitable means to do this are described in U.S. Pat. No. 5,106,360 (Ishiwara et al.) wherein brachytherapy catheter is provided with heating electrical coils in the treatment region of the catheter. Other means such as inflation fluid at elevated temperatures may be employed. Generally, tissue temperature must be less than 100°, preferably less than 60° C. to avoid excess damage to surrounding health tissue. 
         [0020]    The present invention provides a brachytherapy catheter device which is effective, easy to use and which is easy to manufacture. These and other advantages of the present invention are described in more detail in the following written description and the accompanying exemplary drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic perspective view, partially in section, of a brachytherapy device embodying features of the invention. 
           [0022]      FIG. 2  is a transverse cross sectional view of the device shown in  FIG. 1  taken along lines  2 - 2 . 
           [0023]      FIG. 3  is a transverse cross sectional view of the device shown in  FIG. 1  taken along the lines  3 - 3 . 
           [0024]      FIG. 4  is a transverse cross sectional view of the device shown in  FIG. 1  taken along the lines  4 - 4 . 
           [0025]      FIG. 5  is a transverse cross sectional view of the device shown in  FIG. 1  taken along the lines  5 - 5 . 
           [0026]      FIG. 6  is a perspective view of the support member in the embodiment shown in  FIG. 1 . 
           [0027]      FIG. 7  is a perspective view of the distal tip of the device shown in  FIG. 1 . 
           [0028]      FIG. 8  is a longitudinal cross-sectional view of the distal tip shown in  FIG. 7 . 
           [0029]      FIG. 9  is a perspective view of an alternative support member such as shown in  FIG. 6  wherein the raised portions of the adjacent to the recess are provided with heating coils. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    The present invention is directed to devices and methods for treatment of a patient&#39;s body cavity, particularly to deliver asymmetrical radiation into a body cavity such as a cavity left after removal of tissue from the site. While the detailed description is directed to a device configured for treating a patient&#39; breast after tissue removal such as in a lumpectomy, other body sites may also be treated with the device. 
         [0031]      FIGS. 1-8  illustrate a brachytherapy catheter device  10  embodying features of the invention which has an elongated shaft  11 , a distal tip  12 , a treatment location  13  in a distal shaft portion  14  proximal to the distal tip. The device  10  has a balloon  15  on the distal shaft portion  14  which surrounds the treatment location  13 . A hub  16  is mounted on the proximal end of the shaft  11  which has an inflation line  17  with leur connection  18 , a vacuum line  19  with a leur connection  20  and four outer delivery tubes  21 ,  22 ,  23 ,  24  for delivery of a radiation source through the lumens thereof to the treatment location  13  off set from a centrally location longitudinal axis  25  to provide asymmetrical radiation of tissue surrounding the balloon  15 . The leur connections  18  and  20  are provided with threaded caps  26  and  27  respectively to close off the connections. Each of the delivery tubes has a removable cap  28 ,  29 ,  30 , and  31  respectively to close of the delivery tubes until use. A centrally located delivery tube  32  is provided for radiation source delivery along the central longitudinal axis within the treatment location which also has a removable cap  33 . 
         [0032]    The hub  16  has a ridge  34  which is aligned with marker line  35  to provide the physician or other professional the orientation of the treatment location  13 . The elongated shaft  11  may also be provided with depth markings to help in the placement of the balloon  15  within the cavity. 
         [0033]    As shown best in  FIG. 2 , the elongated shaft  11  has eight lumens, four lumens  36 ,  37 ,  38  and  39  equally spaced about the longitudinal axis  25  for radiation source delivery as described above and four equally spaced additional lumens  40 ,  41 ,  42  and  43 , lumen  40  for vacuum application and lumen  42  for inflation fluid delivery to the interior of balloon  15 . Lumens  41  and  44  are not used in this embodiment, but may be used for a variety of functions. A proximal vacuum port  44  is provided in fluid communication with lumen  40  and distal vacuum port  45  (shown best in FIGS.  5  and  7 - 8 ) is provided in the distal tip  12  which is in fluid communication with lumen  40  through the annular space  46  between the central delivery tube  32  and center lumen  47  of support member  48  shown in  FIGS. 2-4 . The support member  48 , which is best shown in  FIG. 6 . 
         [0034]    As shown in  FIGS. 1 ,  3  and  4 , the distal shaft portion  14  is split into four separate longitudinal wall segments  49 ,  50 ,  51  and  52 , with each wall segment having one of the radiation source lumens  36 - 39  and being disposed within one of the recesses  53 - 56  in the exterior surface of support member  48 . Recesses  55 - 56  are not shown in  FIG. 6  but are on the opposite side of support member  48 . The longitudinal wall segments  49 - 52  are slit through the lumens  40 - 43  as best shown in  FIGS. 3-5 . Lumens  40 - 43  are plugged off proximal to the split of the wall segments  49 - 52 . This wall segment structure facilitates the manufacture of the catheter. The elongated shaft may be extruded with all eight lumens  36 - 43  in place and the distal shaft portion  14  is segmented by cutting through lumens  40 - 43  by a cutting blade or other suitable cutting element. The support member  48  may be slid over the central delivery tube  32  with the proximal end of the support member secured within the central lumen of the shaft  11 . The free ends of the slit wall segments  49 - 52  are secured to the distal end of the support member  48 . The balloon  15  may then be secured to the shaft  11  with wound sutures  57  and  58  further securing the ends of the balloon to the shaft. The outer delivery tubes  21 - 24  may extend through lumens  36 - 39  to the distal ends of the wall segments  49 - 52 . Inflation line  17  and vacuum line  19  may likewise extend through lumens  40  and  41  to a location (not shown) proximal to the split of the wall segments  49 - 52 . 
         [0035]    As best shown in  FIGS. 5 ,  7  and  8 , the distal tip  12  has the distal vacuum port  45  which is in fluid communication with the annular space  46  between central delivery tube  32  and lumen  47  of support member  48 . The distal tip  12  is provided with outer source lumen plugs  60 - 63  for plugging lumens  36 - 39  and center source lumen plug  64  for plugging the distal end of central tube  32 . 
         [0036]    The brachytherapy catheter device  10  is readily manufactured. The elongated shaft  11  is extruded, preferably with the lumens  36 - 43  within the wall and the central lumen  46 . The distal shaft portion  14  is cut by a suitable cutting member such as a razor or knife like member to form the plurality of separated longitudinal wall segments  49 - 52 . The support member  48  is preferably machined from an extruded tubular polymeric product to form the recesses  53 - 56  and overall shape and centrally placed within the separated longitudinal wall segments. A tubular member  32  is positioned within the inner lumen of the elongated shaft  11  and may continue to the distal end of the shaft through the inner lumen of the support member  48 . The distal tip  12  is secured to the distal end of the shaft  11  and support member  48  with plug members  60 - 63  inserted into the lumens within the wall segments  49 - 52  and central plug member  64  within the lumen of the centrally disposed tubular member  32 . The distal tip  12  is preferably preformed with the vacuum ports  45 . The distal ends of the separated longitudinal wall segments are secured to the distal end of the device, preferably to the distal end of the support member. The balloon  15  is mounted about the wall segments  49 - 52  and support member  48  with the distal end of the balloon secured to the distal end of the wall segments and support member and the proximal end of the balloon is secured to the elongated shaft proximal to the separated longitudinal wall segments. Preferably, strands or sutures are wrapped around each of the mounted ends of the balloon  15  to provide further support to the ends. The proximal end of the device  10  is similar to the brachytherapy devices previously described in copending applications 11/593,784 and 11/593,789 previously referred to herein. 
         [0037]    A body cavity within a patient may be treated with the device  10  by inserting the distal shaft portion  13  into the desired body cavity, inflating the balloon  15  with inflation fluid to secure the device within the patient and applying a vacuum to either the distal or proximal vacuum ports or both to conform the tissue lining the cavity to the exterior of balloon  15 . A radiation source is advanced through one or more of the source delivery lumens until the radiation source is properly positioned within the treatment location  13  (or prepositioned therein). The radiation source (not shown) is maintained at the treatment location  13  for a prescribe period of time, usually less than 30 minutes and typically a few (5-10) minutes. The radiation source may be placed at several places within the treatment location with within one or multiple source lumens. At the end of the treatment time, the radiation source may be removed from device  10  or the entire device may be withdrawn from the patient. Preferably, the device is left in place so that further radiation treatments may be performed. 
         [0038]    The radiation source for the brachytherapy device  10  can include a solid, liquid or slurried radiation source. Suitable liquid radiation sources include, for example, a liquid containing a radioactive iodine isotope (e.g., I 125  or I 131 ), a slurry of a solid isotope, for example,  198 Au or  169 Yb, or a gel containing a radioactive isotope. Liquid radiation sources are also commercially available (e.g., Iotrex®, Proxima Therapeutics, Inc., Alpharetta, Ga.). The solid radiation source may be a radioactive microsphere available from 3M Company of St. Paul, Minn. A micro miniature x-ray source may also be utilized. The radiation source may be either preloaded into the device  10  at the time of manufacture or may be loaded into the device  10  before or after placement into a body cavity or other site of a patient. Solid radionuclides suitable for use with a device  10  embodying features of the present invention are currently generally available as brachytherapy radiation sources (e.g., I-Plant. TM. Med-Tec, Orange City, Iowa.). Radiation may also be delivered by a device such as the x-ray tube of U.S. Pat. No. 6,319,188. The x-ray tubes are small, flexible and are believed to be capable of being maneuverable enough to reach the desired location within a patient&#39;s body. 
         [0039]    The source delivery lumens of brachytherapy device  10  having features of the invention can be provided with a lubricious coating, such as a hydrophilic material. The lubricious coating preferably is applied to the elongate shaft  12  or to the cavity filling member, if one is present or both to reduce sticking and friction during insertion of a device  10 . Hydrophilic coatings such as those provided by AST, Surmodics, TUA Systems, Hydromer, or STS Biopolymers are suitable. 
         [0040]    A device  10  having features of the invention may also include an antimicrobial coating that covers all or a portion of the device  10  to minimize the risk of introducing of an infection during extended treatments. The antimicrobial coating preferably is comprised of silver ions impregnated into a hydrophilic carrier. Alternatively the silver ions are implanted onto the surface of the device  10  by ion beam deposition. The antimicrobial coating preferably is comprised of an antiseptic or disinfectant such as chlorhexadiene, benzyl chloride or other suitable biocompatible antimicrobial materials impregnated into hydrophilic coatings. Antimicrobial coatings such as those provided by Spire, AST, Algon, Surfacine, Ion Fusion, or Bacterin International would be suitable. Alternatively a cuff member covered with the antimicrobial coating is provided on the elongated shaft of the delivery device  10  at the point where the device  10  enters the skin. 
         [0041]      FIG. 9  illustrates a modified support member  48  which is provided with a heating coil  70  to raise the temperature of tissue in the cavity lining either simultaneously with or sequentially to irradiation of the cavity lining as previously described. While  FIG. 9  depicts a heating  70  on one raised portion of the support member  48 , a heating element may be provided on a plurality of raised portions of the support member. Preferably, the heating coils are powered by RF energy and are connected to a suitable high frequency generator. Voltage, current, frequency and duty factor may be adjusted to provide a suitable thermal treatment to tissue lining the cavity to augment the irradiation thereof. Other means may include heating the inflation fluid within the balloon  15 . The heating of the inflation fluid may be exterior to the device  10 . 
         [0042]    While particular forms of the invention have been illustrated and described herein, it will be apparent that various modifications and improvements can be made to the invention. Additional details of the brachytherapy catheter devices may be found in the patents and applications incorporated herein. To the extent not otherwise disclosed herein, materials and structure may be of conventional design. 
         [0043]    Moreover, individual features of embodiments of the invention may be shown in some drawings and not in others, but those skilled in the art will recognize that individual features of one embodiment of the invention can be combined with any or all the features of another embodiment. Accordingly, it is not intended that the invention be limited to the specific embodiments illustrated. It is therefore intended that this invention be defined by the scope of the appended claims as broadly as the prior art will permit. 
         [0044]    Terms such as “element”, “member”, “component”, “device”, “means”, “portion”, “section”, “steps” and words of similar import when used herein shall not be construed as invoking the provisions of  35  U.S.C. §112(6) unless the following claims expressly use the terms “means for” or “step for” followed by a particular function without reference to a specific structure or a specific action. All patents and all patent applications referred to above are hereby incorporated by reference in their entirety.