Abstract:
A medical device sheath apparatus including: a fitting being suitable for receiving the medical device in a self sealing manner; a first sheath for receiving the medical device as it passes through the fitting; a second sheath surrounding the first sheath; a dilator defining a treatment area, coupled to at least the second sheath, and being suitable for dilating a bodily cavity and passing therapeutic or diagnostic energy in such forms as electromagnetic radiation or acoustic energy there through; and, a window operatively positioned with respect to the first sheath so as to enable viewing of an area substantially adjacent the second sheath upon insertion of the medical device into the apparatus.  
     A method for irradiating at least a portion of a bodily cavity including: providing a sheath apparatus including: a fitting being suitable for receiving the medical device in a self sealing manner; a first sheath for receiving the medical device as it passes through the fitting; a second sheath surrounding the first sheath; a dilator defining a treatment area, coupled to at least the second sheath, and being suitable for dilating a bodily cavity and passing therapeutic or diagnostic energy in such forms as electromagnetic radiation or acoustic energy there through; and, a window operatively positioned with respect to the first sheath so as to enable viewing of an area substantially adjacent the second sheath upon insertion of the medical device into the apparatus; inserting at least a portion of the medical device into the apparatus; positioning the medical device containing apparatus in the bodily cavity using direct viewing through the window and the medical device; and, irradiating the portion of the bodily cavity through the apparatus using the medical device.  
     A method for making a medical device sheath apparatus including: coupling a first sheath to a fitting being suitable for receiving the medical device in a self sealing manner; coupling a second sheath to the fitting so as to surround the first sheath; coupling a dilator defining a treatment area and being suitable for dilating a bodily cavity and passing therapeutic or diagnostic energy in such forms as electromagnetic radiation or acoustic energy there through to the second sheath; and, coupling the first sheath to a window operatively positioned with respect to the first sheath so as to enable viewing of an area substantially adjacent the second sheath upon insertion of the medical device into the apparatus.

Description:
RELATED APPLICATION  
       [0001]    This application claims priority of U.S. patent application Ser. No. 60/418,664, entitled MEDICAL DEVICE SHEATH APPARATUS AND METHOD OF MAKING AND USING SAME, filed Oct. 15, 2002, the entire disclosure of which is hereby incorporated by reference as if being set forth in its entirety herein. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to systems and methods for treating medical conditions, and more particularly to systems and methods for treating medical conditions associated with a body cavity or lumen.  
         BACKGROUND OF THE INVENTION  
         [0003]    Endoscopes are generally used to examine various biological cavities, such as those in the alimentary canal or the bladder. Such may be biological cavities of a human or otherwise. A physician typically has a limited view of the interior of the cavity in which the distal end of the endoscope is located, due to the fact that tube like organs, such as the esophagus, intestine, and bladder, may be relatively soft and pliable such that the organ collapses about the endoscope. In order to have a better view of the cavity, air or liquid (such as water) may be traditionally forced into the cavity causing the cavity to temporarily expand.  
           [0004]    Devices have generally been developed to distend tube-like organs with hardened or scarred tissue. One such device used by physicians is the balloon catheter. In the cardiovascular system, balloon catheters are used to open blocked or significantly narrowed arteries. In the gastrointestinal system, a modified balloon catheter, or balloon dilator, may be used to exert a radial force on the surrounding walls of tube-like organs, for the purpose of dilating strictures. Balloon dilators are commonly used in the gastrointestinal tract for strictures of the esophagus, pylorus, duodenum, sphincter of odi, biliary tree and colon.  
           [0005]    Balloon catheters and dilators have also been used for expansion without the exertion of large radial forces. These balloon dilators are instead used to hold an organ open for an extended period of time, usually for a treatment of some kind. This treatment may include delivering medicaments to a specific site within the cardiovascular system, or the activation of a photosensitizing agent in a variety of organs, for example.  
           [0006]    Devices have also been proposed to expand non-tubular organs in order to create a uniform surface for the activation of a photosensitizing agent. Such organs include the uterus and the bladder, for example.  
           [0007]    Regardless, such distending devices may conventionally be positioned with respect to a target tissue with the aid of guidewires, or specialized introducers, being passed through the lumen of an endoscope, or by being passed “blindly” through connecting body lumens. However, there is typically no direct viewing of the positioning procedure or the target tissue. Therefore, difficulties exist in remotely and effectively treating a disease or ailment. Further, using guidewires typically requires, multiple insertions into the cavity to perform a treatment. Generally, the more insertions required, the greater the chance for damage to surrounding tissue. For example, in a typical guidewire related gastrointestinal PDT procedure, a physician typically first inserts an endoscope to determine the treatment site. Once the site is located, a guidewire is typically inserted into the instrument channel of the endoscope. The endoscope is then withdrawn and the guidewire is left behind at the treatment site. Next, a balloon dilator is typically inserted using the guidewire as a central axis. To view the site, the endoscope is then reinserted alongside the dilator. When the procedure is complete, all devices are removed from the site.  
           [0008]    In situations where devices are passed either through an endoscope or are passed “blindly”, there is a risk that the device may not be properly positioned at the target tissue, or more significantly, pass into unintended tissue and/or lumens causing harm to the patient. It is generally desirable to mitigate this risk. Further, it is generally desirable to minimize the number of insertions that must be performed to treat an area of interest.  
         SUMMARY OF THE INVENTION  
         [0009]    A medical device sheath apparatus including: a fitting being suitable for receiving the medical device in a self sealing manner; a first sheath for receiving the medical device as it passes through the fitting; a second sheath surrounding the first sheath; a dilator defining a treatment area, coupled to at least the second sheath, and being suitable for dilating a bodily cavity and passing therapeutic or diagnostic energy in such forms as electromagnetic radiation or acoustic energy there through; and, a window operatively positioned with respect to the first sheath so as to enable viewing of an area substantially adjacent the second sheath upon insertion of the medical device into the apparatus.  
           [0010]    A method for irradiating at least a portion of a bodily cavity including: providing a sheath apparatus including: a fitting being suitable for receiving the medical device in a self sealing manner; a first sheath for receiving the medical device as it passes through the fitting; a second sheath surrounding the first sheath; a dilator defining a treatment area, coupled to at least the second sheath, and being suitable for dilating a bodily cavity and passing therapeutic or diagnostic energy in such forms as electromagnetic radiation or acoustic energy there through; and, a window operatively positioned with respect to the first sheath so as to enable viewing of an area substantially adjacent to the second sheath upon insertion of the medical device into the apparatus; inserting at least a portion of the medical device into the apparatus; positioning the medical device containing apparatus in the bodily cavity using direct viewing through the window and the medical device; and, irradiating the portion of the bodily cavity through the apparatus using the medical device.  
           [0011]    A method for making a medical device sheath apparatus including: coupling a first sheath to a fitting being suitable for receiving the medical device in a self sealing manner; coupling a second sheath to the fitting so as to surround the first sheath; coupling a dilator defining a treatment area and being suitable for dilating a bodily cavity and passing therapeutic or diagnostic energy in such forms as electromagnetic radiation or acoustic energy there through to the second sheath; and, coupling the first sheath to a window operatively positioned with respect to the first sheath so as to enable viewing of an area substantially adjacent the second sheath upon insertion of the medical device into the apparatus.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    Understanding of the present invention will be facilitated by consideration of the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which like numerals refer to like parts, and,:  
         [0013]    [0013]FIG. 1 illustrates an isometric view of an apparatus according to an aspect of the present invention;  
         [0014]    [0014]FIG. 2 illustrates an isometric view of the apparatus of FIG. 1 having a medical device partially inserted therein;  
         [0015]    [0015]FIG. 3 illustrates a fitting suitable for use with the apparatus of FIG. 1;  
         [0016]    FIGS.  4 A- 4 E illustrate various views of a seal retainer suitable for use with the fitting of FIG. 3;  
         [0017]    FIGS.  5 A- 5 E illustrate various views of a seal suitable for use with the fitting of FIG. 3;  
         [0018]    FIGS.  6 A- 6 F illustrate various views of a seal housing being suitable for use with the fitting of FIG. 3;  
         [0019]    FIGS.  7 A- 7 D illustrate various views of a sheath lumens suitable for use with the apparatus of FIG. 1;  
         [0020]    FIGS.  8 A- 8 F illustrate various views of an outer sheath suitable for use with the sheath lumens of FIGS.  7 A- 7 D;  
         [0021]    FIGS.  9 A- 9 F illustrate various views of a distal window suitable for use with the apparatus of FIG. 1;  
         [0022]    [0022]FIG. 10 illustrates an exploded view of the apparatus of FIG. 1; and,  
         [0023]    FIGS.  11 A- 11 C illustrate cross-sectional views of the apparatus of FIG. 2, having an endoscope positioned at various positions therein for treatment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements found in endoscopic systems and radiating treatment methods. Those of ordinary skill in the art will recognize that other elements are desirable and/or required in order to implement the present invention. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein. The disclosure herein is directed to all such variations and modifications to such systems and methods known to those skilled in the art.  
         [0025]    According to an aspect of the present invention, a sheath like apparatus may be provided and used that may be advantageously compatible with existing endoscopic equipment, and be used to expand, directly view and irradiate target tissue within a body cavity or lumen. It should be understood that while endoscope sheaths have generally been developed in order to prevent pathogen transfer from a cavity in which the scope is placed to the instrument itself, and in turn from person to person, these devices typically provide no other significant therapeutic benefits or advantages.  
         [0026]    According to an aspect of the present invention, there is provided a sheath-like device which may be used in conjunction with, or otherwise associated with such as by substantially encasing, an endoscope and introduced into a body cavity or lumen. Such a device may allow the cavity or lumen, or portion thereof corresponding to a treatment area, to be formed or dilated to a desired shape, so as to be substantially spherical, cylindrical, ellipsoidal or ovoid, for example. According to an aspect of the present invention, such a device may provide means to inspect, diagnose and/or treat the cavity or lumen with electromagnetic radiation, such as light or acoustic energy such as ultrasound. Energy delivered in this manner may allow for more accurate diagnosis or treatment than may otherwise be conventionally possible. Provided energy may also effect treatment through direct physical effect on surrounding tissue, such as by cauterization or hypothermia, for example. Or, it may effect treatment by causing a chemical reaction, such as in conjunction with a photosensitizing agent or precursor present in target tissue, for example. According to an aspect of the present invention, enhanced visualization of the cavity or lumen being irradiated may be achieved.  
         [0027]    According to an aspect of the present invention, there may be provided and used a sheath-like apparatus into which an endoscope may be inserted, so as to facilitate examination and therapy within a biological cavity using a single insertion of the apparatus. Near an end of the apparatus, a bladder or balloon portion positionable with the aid of an elongated sheath portion may be provided. The balloon portion may be inflated with a suitable fluid, such as a liquid or gas, to thereby cause it to swell and provide an outward force that may tend to dilate or deform a biological cavity into which it is inserted. Such dilation may be of a desirably and predictably smooth shape based upon characteristics of the balloon so as to enhance uniformity or irradiation or illumination provided therethrough. For example, the balloon may be substantially nondistensible. Alternatively, it may be desirable that the balloon portion be distensible or partially distensible based upon intended operational characteristics.  
         [0028]    According to an aspect of the present invention, the apparatus may generally include a fitting which includes a seal housing, a seal which is dimensioned to receive an endoscope while creating a substantially air-tight seal about it, and a seal retainer. The apparatus may generally include a substantially transparent outer sheath including a non-distensible balloon; a substantially transparent inner sheath; a substantially transparent viewing window; a tube positioned between the inner and outer sheaths being suitable for delivering at least one fluid, such as air, to a distal end of the treatment apparatus, such as to terminate distal to the balloon and/or viewing window for the evacuation of matter that may accumulate distal to the balloon and/or window during therapy; and a second tube which terminates within the seal housing and is intended to transport a fluid or air for the purpose of inflating the balloon. The viewing window may have an antireflection coating on one or more surfaces.  
         [0029]    The balloon may or may not have either a reflective, partially reflective or absorptive coating applied to one or more surfaces, or a portion thereof, to enhance and/or limit treatment to a specific target area of tissue within a cavity. The balloon may have an optical sensor or sensing fiber affixed to or embedded in it.  
         [0030]    By inserting an endoscope into the apparatus, sufficient rigidity may be attained to allow the apparatus to be inserted into a biological cavity such as an esophagus. Once inside the esophagus, a physician may examine the inside of the esophagus by looking through the transparent viewing window, rinse the interior of the esophagus with water or saline that is introduced through the apparatus, introduce air, suction liquid, and properly position the apparatus for therapy. When properly positioned, air may be introduced into the balloon causing the balloon to inflate. The inflated balloon may substantially anchor the apparatus in the biological cavity allowing the endoscope to be withdrawn a distance equivalent to a treatment length. The treatment length may be determined through the endoscope by visual reference to markings within the apparatus or by visual reference to graduations on the endoscope itself, for example. An energy delivering device, such as a light emitting fiber, may then be inserted through an instrument channel in the endoscope, until it contacts the viewing window or a distal end of the apparatus, thereby exposing a portion of the energy delivering device to the cavity, such as a length of light emitting fiber suitable for treating a treatment area of tissue, i.e., a treatment length.  
         [0031]    Referring now to FIG. 1, there is shown an isometric view of an apparatus  10  according to an aspect of the present invention. Apparatus  10  generally includes three functional areas: a proximal fitting  20 , sheath lumens  30  and distal window  40 . An air/water/suction line  12  and inflation/deflation line  14  are shown extending from the proximal fitting  20  of the apparatus  10 .  
         [0032]    Referring now also to FIG. 2, there is shown an isometric view of the apparatus  10  of FIG. 1 having a medical device  50  partially inserted therein. Device  50  may generally take the form of an apparatus or instrument for visually examining the interior of a bodily canal or a hollow organ, such as the colon, bladder or stomach. Device  50  may take the form of an endoscope or gastroscope, for example. Device  50  may be referred to herein as an endoscope for purposes of non-limiting explanation only. Endoscope  50  passes through proximal fitting  20  and into an enclosed space formed by the sheath lumens  30 . A radiation emitting device  60 , such as a light emitting fiber, is shown extending through a biopsy or instrument channel of endoscope  50 . Of course, any device being suitable for emitting radiation at wavelengths selected for therapeutic benefit of tissue and being inserted into device  50  may be used. Additionally, emitting device  60  may be connected to an activating source so as to couple emitted radiation into a treatment cavity and cause irradiation of surrounding tissue. For example, where device  60  takes the form of an optical fiber, a laser or other suitable light-generating device (not shown) optically coupled to the fiber may be used. Alternatively, device  60  may generate emitted radiation itself.  
         [0033]    Terminal fittings of the air/water/suction line  12  and the inflation/deflation line  14  may be respectively connected to sources of air, water, or suction and pressure/vacuum respectively (not shown). Endoscope  50  may be used in conjunction with apparatus  10 , such that proximal fitting  20  may provide a primary interface between apparatus  10  and endoscope  50 . Proximal fitting  20  may further provide a grip by which to maneuver apparatus  10 .  
         [0034]    Referring now also to FIG. 3, proximal fitting  20  generally includes a seal retainer  70 , seal  80  and seal housing  90 . Sealing may be largely accomplished using a suitable elastomeric material or, alternatively, a mechanically or pneumatically actuated seal. Seal retainer  70  and seal housing  90  may be acrylic in nature, but may be formed of any suitable, non-porous material that would allow for a good bonding surface for the other components as will be understood by one possessing an ordinary skill in the pertinent arts. Seal  80  may be formed of a parylene coated silicone, but may be largely formed out of any suitable elastomeric material that may have applied to it, a friction reducing coating. Seal retainer  70 , seal  80  and housing  90  may be designed to take advantage of a repeatable manufacturing process, such as injection molding.  
         [0035]    Referring now also to FIGS.  4 A- 4 D, there are shown various views of a seal retainer suitable for use as seal retainer  70  of FIG. 3. Seal retainer  70  may generally take the form of a truncated cone having a small taper suitable for creating a locking fit with a mating portion of seal housing  90 , as well to aid in ejection during a molding process, for example. A countersink like through hole or aperture  72  may be provided to guide a distal tip of endoscope  50  into place so as to pass through retainer  70  and into sheath portion  30  (FIGS. 1 and 2). Retainer  70  may also include two through holes or apertures  74  sized to fit a strain relief for inflation/deflation  12  and air/water suction  14  lines (FIGS. 1 and 2). Along an outer tapered surface of retainer  70  may be provided a key like feature  76  suitable for dictating positioning during assembly. This may serve to mitigate a risk of misalignment with mating holes in seal  80 . Referring now also to FIGS.  5 A- 5 D, there are shown various views of a seal suitable for use as seal  80  of FIG. 3. Seal  80  may be configured to provide multiple seals. Seal  80  may generally comprise a flat disk portion  82  and an o-ring-like gasket  84  that lies around a perimeter of the disk  82  and a tubular portion  86  extending longitudinally from disk  82 . Seal  80  may further include a bore  81  through disk  82  and tubular portion  86 . Tubular portion  86  may be relatively thin walled to accommodate bore  81 . Disk  82  and o-ring  84  may be compressed between a distal face of seal retainer  70  and a step in a bore of seal housing  90  when assembled therewith.  
         [0036]    Seal  80  may further include a plurality, such as four (4), fin like protrusions  83  extending outwardly from and along tubular portion  86  of seal  80 . Of course, any suitable shape for portion  83  may be used though. These protrusions may serve to provide rigidity to tubular portion  86  to prevent roll back upon removal of endoscope  50 . Second, when fully assembled in seal housing  90 , the distal face of the fins may contact at least one protrusion within the housing  90  to prevent elongation and therefore narrowing of seal  80  when endoscope  50  is inserted through bore  81 .  
         [0037]    Seal  80  may further include apertures  89  passing through disk portion  82  and being suitable for passing air/water/suction line  12  and inflation/deflation line  14  therethrough. Apertures  89  may be undersized in comparison to tubes being passed through them. Further, disk  82  may include a relatively thicker portion  87  through which apertures  83  pass to provide a greater sealing surface along the length of the inserted lines  12 ,  14  as they pass through seal  80 . Portion  87  of increased thickness may also be configured to act as a key, forcing alignment of apertures  89  of the seal  80  with apertures  74  through seal retainer  70  (FIG. 4A) as well as with apertures through seal housing  90  which correspond to lines  12 ,  14 .  
         [0038]    Seal  80  may provide a seal between seal retainer  70  and seal housing  90 . Seal  80  may provide a seal about lines  12 ,  14  where they pass through apertures  89 . Seal  80  may provide for a seal between an inner wall of tubular portion  86  and endoscope  50  when endoscope  50  is passed through bore  81 . An inner diameter of tubular portion  86  may be relatively undersized, such that when endoscope  50  is passed therethrough, tubular portion  86  expands to allow endoscope passage.  
         [0039]    Wall thickness and durometer of silicone composing seal  80  may be adjusted during manufacturing to obtain desired radial force operability. By adjusting the seal length and applying a parylene coating during manufacturing, the friction between the seal and the scope can be adjusted to allow for smooth insertion and removal of the endoscope into and from apparatus  10 , for example. The desired friction may also be set so that movement of endoscope  50  relative to the sheath assembly  10  should not inadvertently occur during use, absent force being applied to endoscope  50  by a physician, for example. Tubular portion  86  may be tapered at one or both longitudinal ends to ease insertion and/or removal of endoscope  50 , for example. As will be recognized by one possessing an ordinary skill in the pertinent arts, when all three seals are effected, apparatus  10  defines a substantially closed system that can be pressurized.  
         [0040]    Referring now also to FIGS.  6 A- 6 F, there are shown various views of a seal housing being suitable for use as seal housing  90  of FIG. 3. Seal housing  90  may serve primarily as a transition piece from seal  80  to sheath lumens  30  (FIG. 1). Housing  90  may generally take the form of a series of concentric cones forming a plurality of steps in an internal bore thereof, for example.  
         [0041]    Housing  90  may include a portion  92  adapted to receive and position seal retainer  70 . A first step that decreases the inner diameter of housing  90  may mate with flat disk portion  82  of seal  80 , so as to cooperate as a sealing face. This first step may further include a small channel along its perimeter that mates with o-ring portion  84  of seal  80 . A second portion  94  may include internally projecting fins  95  similar to fins  83  (FIG. 5A) to facilitate securing seal retainer  70  in a substantially centralized position within a bore of housing  90  and reduce seal elongation by retaining a proximal end of seal  80 . Fins  95  may be spaced to facilitate alignment of seal  80 . Substantially adjacent a longitudinal end of portion  94  substantially distal to portion  92 , a small thin walled protrusion  93  that acts as a positive stop for fins  83  of seal  80 , preventing elongation upon endoscope insertion, may be provided. Further, two apertures  97 ,  99  passing through this same end of portion  94  substantially distal from portion  92  may be provided. A larger of the two apertures  99  may be substantially centralized and sized to allow endoscope  50  passage. Aperture  99  may also pass through a tapered protrusion  98  that for a more proximal portion, substantially adjacent to section  94 , may be teardrop shaped in cross section. An exterior surface of the tear dropped portion of protrusion  98  may serve as a bonding site for an outer sheath, as will be discussed. Protrusion  98  may then step down to a substantially circular cross-section, which may serve as a bonding site for an inner sheath, as will be discussed. Aperture  97  may be smaller, and adapted to pass through only the teardrop shaped portion of protrusion  98 , exiting at or near the step down to the smaller, substantially circular cross-section. Aperture  97  may be used to provide access to a space between inner and outer sheaths, allowing for passage of the air/water/suction line  12  and inflation/deflation line  14 . Aperture  97  may be positioned with reference to other keying features in the proximal fitting components to allow for a straight run, or substantially straight run, of the air/water/suction line  12  and/or inflation/deflation line  14 .  
         [0042]    Referring now also to FIGS.  7 A- 7 D, there are shown various views of a sheath lumens suitable for use as sheath lumens  30  of FIG. 1. Sheath lumens  30  generally includes an inner sheath  32 , air/water/suction line  12 , inflation/deflation line  14 , and an outer sheath/balloon  34 . Inner sheath  32  and outer sheath/balloon  34  may be formed of Polyethylene Terephthalate (PET). Air/water/suction line  12  and inflation/deflation line  14  may be formed of Pebax  72 D. Of course, either sheath  32 ,  34  or lines  12 ,  14  could be made out of any suitably flexible, thin walled plastic tubing or elastomeric material. According to an aspect of the present invention, an optically clear or radiation transmissive material may be utilized so as to pass treatment radiation therethrough and/or allow for direct visualization of an inflated biologic cavity. For example, non-compliant materials such as thermoplastics may make suitable choices.  
         [0043]    Generally, inner sheath  32  may take the form of a thin walled (for example 0.001″) tube that runs substantially the length of the sheath  30 . A first end of inner sheath  32  may be tapered to fit over the tapered, circular cross section distal protrusion  98  of seal housing  90 . An inner diameter of inner sheath  32  may be sized to allow passage of endoscope  50  therethrough. Inner sheath  32  may also serve to effectively limit an area in which optical fiber  60  (FIG. 2) used in treatment will be able to wander.  
         [0044]    Generally, air/water/suction line  12  may be small in diameter (for example having a 0.072″ outer diameter) and run substantially the length of sheath  30 . Line  12  may terminate substantially at or near distal window  40 . As set forth, line  12  may further pass through proximal fitting  20 . Further, from the proximal fitting  20  a length of tubing may continue as a pigtail, terminating at a luer lock fitting, for example. To prevent movement of line  12 , it may be banded to inner sheath  32 . Accordingly, endoscope  50  may be effectively insulated from air/water/suction line  12  by inner sheath  32 .  
         [0045]    Generally, inflation/deflation line  14  may be small in diameter (for example having a 0.072″ outer diameter) and terminate in a substantially free floating manner within seal housing  90  (FIG. 6A). As set forth, line  14  may further pass through proximal fitting  20 . Further, from the proximal fitting  20  a length of tubing may continue as a pigtail, terminating at a luer lock fitting, for example. To prevent movement of line  14 , it may also be banded to inner sheath  32 . Accordingly, endoscope  50  may be effectively isolated from inflation/deflation line  14  by inner sheath  32 .  
         [0046]    Referring now also to  8 A- 8 F in conjunction with  7 A- 7 D in particular, there are shown various views of an outer sheath suitable for use as outer sheath/balloon  34  of FIGS.  7 A- 7 D. According to an aspect of the present invention, outer sheath/balloon  34  may be seen to generally include a proximal taper  100 , a cylindrical main lumen  102 , a balloon  104  and a distal mating portion  106 . The last two features can be a separate component from the other two, or integrally formed therewith. The outer sheath/balloon  34  may take the form of a thin walled (0.001″) tube. A cross section of taper  100  may be generally tear drop in shape, designed to mate with the protrusion  98  of the same shape of seal housing  90 . An elongated cylindrical main lumen  102  may be set off-axis from inner sheath  32  so as to allow for the passage of the air/water/suction line  12 . A small cavity may be formed between inner sheath  32  and outer sheath  34  along the length. The shape of balloon portion  104  may at least partially depend on the type of biological cavity it is intended to be inflated in. In the illustrated, non-limiting instance it is shown as cylindrical, with an abrupt proximal and distal ending that may be suitable to fit within a patient&#39;s esophagus. The length and diameter of the balloon  104  cylinder can be manufactured in a variety of sizes depending on treatment requirements. Balloon  104  may also be coated on specific sections or in a pattern like manner to provide a specific treatment area, improve light efficiency to the treatment area, or improve uniformity, for example. Suitable coatings may be reflective, such as titanium oxide, gold, aluminum, silver or other metals in the case of light irradiation. Suitable coatings may be absorptive, such as carbon black in the case of light irradiation. Such coating may at least partially define treatment area within a biological cavity which balloon  104  is inserted, by facilitating unidirectional irradiation for example. Balloon  104  may be semi-permeable, to allow an oxygenated fluid passage to tissue being treated. Distal mating portion  106  may be of a generally teardrop cross section that is designed to mate with distal window  40  (FIG. 1). This section  106  may be positioned so as to realign the axis of the outer sheath  34  to the inner sheath  32  and distal window  40  (FIG. 1). The balloon portion may be bonded to outer sheath main lumen  102 .  
         [0047]    Referring now also to FIGS.  9 A- 9 F, there are shown various views of a distal window suitable for use as distal window  40  of FIG. 1. Generally, distal window  40  may take the form of a substantially planar, non-planar or lens shaped member, by way of non-limiting example only, that may be made of acrylic to provide a substantially optically clear, non-distorting window. Of course, any other material that provides these features and may be bonded to may be acceptable for use. Window  40  generally includes a tapered protrusion  42  with a circular cross section to provide a bonding site for inner sheath  32  (FIGS.  7 A- 7 D). Window  40  may then step up to a tapered section  94  with a teardrop cross section suitable for providing a bonding site for outer sheath/balloon  34 . A small ridge  46  may serve as a positive stop for outer sheath/balloon  34 . Passing through the bonding site for the outer sheath/balloon  34  may be a small oval or ellipse shaped bore  48 , which has a small step within it, and is hooded  49  on an end opposite to protrusion  42 . Bore  48  may be designed to accept a distal end of the air/water/suction line  12  such that the internal step is positioned to act as a positive stop preventing over insertion. Hood  49  may serve to direct a stream of fluid passing through air/water/suction line  12  down across distal window  40 . The deflecting surface of the hood may be angled so that the fluid passes over an outer surface of window  40 . Viewing windows may be placed at other positions relative to balloon  104  as will be well understood by those possessing an ordinary skill in the pertinent art though. Further, viewing may be facilitated directly through balloon  104 , for example, such that balloon  104  itself forms a viewing window.  
         [0048]    Referring now also to FIG. 10, there is shown an exploded view of an embodiment of apparatus  10  of FIG. 1. Apparatus  10  of FIG. 10 may be assembled in the following manner. Inner sheath  32  may be adhered to seal housing  90 . The air/water/suction line  12  may be fed through aperture  97  in seal housing  90  such that a length slightly longer than the distal end of inner sheath  32  is provided. The air/water/suction line  12  may then be banded to the inner sheath  32 . An area of the inner sheath  32  corresponding to balloon  104  is preferably not banded. Outer sheath  34  may then be adhered to housing  90 . Balloon  104  may then be slid onto the outer sheath  34  such that a distal end of balloon  104  is behind, or shorter than, a distal end of inner sheath  32 . Air/water/suction line  12  may then be fed into and secured within aperture  48  of window  40 , such as by adhering. Inner sheath  32  may then be adhered to the corresponding area of portion  42  of distal window  40 , taking care to ensure that the air/water/suction line  12  remains substantially in-line. Balloon  104  may then be adhered up to the ridge  46  on window  40  and to the outer sheath  34 . Seal  80  may then be inserted into seal housing  90  while feeding air/water/suction line  12  through one of the apertures  89 , such as a left one, taking care to ensure full seating of seal  80 . Inflation/deflation line  14  may then be fed through the other of the apertures  89  in the seal  80 . The air/water/suction and inflation/deflation lines  12 ,  14  may then be fed through apertures  74  of seal retainer  70 . Seal retainer  70  may then be fully seated within housing  90  such that the proximal faces thereof are substantially in plane. The air/water/suction and inflation/deflation lines  12 ,  14  may then be cut to provide pigtails of appropriate length, such as 25 cm. Strain reliefs  110  may then be slid onto and adhered to the ends of the air/water/suction and inflation/deflation lines  12 ,  14 . Suitable strain reliefs may take the form of thin Pellethane tubes, for example. Female luer locks may then be secured to the free ends of the air/water/suction and inflation/deflation lines  12 ,  14 , and attached to the strain reliefs.  
         [0049]    In use, endoscope  50  may be inserted through the seal retainer  70 , seal  80  and seal housing  90 , and into the inner sheath  32  such that the distal end of the endoscope  50  becomes proximate to the distal end of the inner sheath  32  (i.e., adjacent to the viewing window  40 ). When endoscope  50  is fully inserted, sheaths  32 ,  34  may become less flexible in nature due to the more radially rigid endoscope  50  housed within them and is ready to be used in a biological cavity (e.g., an esophagus).  
         [0050]    When the distal portion of endoscope  50  is proximate to the distal end of the inner sheath  32 , endoscope  50  may be positioned to receive, and transmit, images of a cavity in which the sheath and endoscope are inserted; through the viewing window  40 . If the viewing window becomes hazy or is covered by matter (which may be, for example, biological in nature), a physician can direct water or air through the air/water/suction line  12  to remove the matter from the viewing window  40 . Similarly, if sufficiently small matter and/or fluid in nature should become adjacent to window  40 , the matter may be removed by sucking it through the air/water/suction line  12 .  
         [0051]    By injecting a suitable material, such as a gas, air or liquid for example, between the inner and outer sheaths  32 ,  34  (by using inflation/deflation line  14  for example), balloon  104  will tend to inflate and deform a biologic cavity in which it is inserted. Similarly, if fluid pumped into apparatus  10  is withdrawn (for example, by sucking the fluid back out through inflation/deflation line  12 ), the space between inner and outer sheaths and between the inner sheath and endoscope scope will deflate.  
         [0052]    Referring now to FIGS. 11A and 11 B, there are illustrated cross-sectional views showing the distal end of the endoscope  50  at a first position proximate the distal end of the inner sheath  32  wherein the balloon  104  is in a deflated state and adjacent a target region of a biologic cavity. When in this first position, the balloon  104  may be inflated (by pumping air, water, etc. through the inflation line  12  to expand the target region by making a uniform shape, for example). Simultaneously, the space between the inner and outer sheaths  32 ,  34 , and/or between the inner sheath and the endoscope may be inflated.  
         [0053]    The target region may be affected by a disease or ailment such as Barrett&#39;s Esophagus and may additionally contain a photosensitizing agent or precursor such as that described in U.S. Pat. Nos. 5,955,490, 5,422,093, 5,234,940, 5,211,938, 5,097,262 and in James C. Kennedy et al.,  Photodynamic Therapy  ( PDT )  and Photodiagnosis  ( PD )  Using Endogenous Photosensitization Induced by  5- Aminolevulinic Acid  ( ALA ):  Mechanisms and Clinical Results,  14 J. CLINICAL LASER MEDICINE &amp; SURGERY 289-304 (1996), each of which is incorporated herein by reference in its entirety.  
         [0054]    After the balloon  104  is inflated, the physician may pull on the endoscope  50  while holding the proximal fitting  20  thereby withdrawing the endoscope  50  relative to the viewing window  40 ; the endoscope being proximally withdrawn to a second position, thereby defining a treatment region between the distal end of the endoscope  50  and the proximal end of the viewing window  40  (FIG. 11B).  
         [0055]    Referring now also to FIG. 11C, after the endoscope  50  is withdrawn, light emitting fiber  60  may be extended through the bores of apparatus  40 , such that it projects into the treatment region between the distal end of the endoscope  50  and the proximal end of the viewing window  40 . When the fiber  60  is extended, the physician may irradiate the target region with light. The light, which may take the form of laser emissions, passes through the inner sheath  32  and the balloon  104  of the outer sheath/balloon  34  and is absorbed by portions biologic cavity in which it is inserted, including the target region. The light delivered by the fiber may be in the infrared, visible, and/or ultraviolet regions of the spectrum, although if the intended treatment utilizes a photosensitizer, the wavelengths of light will be specific to those capable of activating said photosensitizer. The fiber that delivers the light may be configured in a variety of geometries including cylindrical, spherical and spot projection, with the preferred embodiment being cylindrical.  
         [0056]    After the target region has been effectively treated, the combination of the endoscope  50 , inner sheath  32 , and outer sheath  34  may be removed in a manner similar to that by which the combination was inserted. Specifically, the light emitting fiber  60  may be withdrawn back into the endoscope  50 , and the endoscope  50  is pushed back to the first position at which its distal end is proximate to the distal end of the inner sheath  32 , while the balloon  104  remains inflated. Subsequently, the balloon  104  may be deflated. After deflating the balloon  104 , the combination of the endoscope  50 , inner sheath  32 , and outer sheath  34  may be removed from the biologic cavity, such as an esophagus. Alternatively, apparatus  10  may be left in place to facilitate effecting other treatments or procedures, in which case endoscope  50  may be withdrawn, and if necessary or desirable, balloon  104  inflated to maintain its relative position in the cavity while endoscope  50  is being withdrawn.  
         [0057]    According to an aspect of the present invention, seal  80  may take the form of a locking or passive seal.  
         [0058]    According to an aspect of the present invention, air/water/suction line  12  could be split into an air/water line and a suction line. The air/water line would continue to use the hood feature on the distal window for displacing the spray of fluid. The suction line may be provided with a separate bore through the distal window  40  that was not hooded, to allow direct suction for example. An additional suction port could be positioned proximal to the balloon to remove fluid build up during treatment. According to an aspect of the present invention, air/water/suction line  12  could be removed altogether, which could allow for the removal of the outer sheath and the necessary bonding sites on the proximal fitting  20  and distal window  40 . In such a case, balloon  104  may be adhered proximally and distally to the inner sheath  32 . The inner sheath  32  may be allowed to communicate with the balloon  104 .  
         [0059]    According to an aspect of the present invention, air/water/suction line  12  could be removed altogether, which could allow for the removal of the inner sheath and the necessary bonding sites on the proximal fitting  20  and distal window  40 . In such a case, balloon  104  may be adhered proximally and distally to the outer sheath. The outer sheath may be allowed to communicate with the balloon  104 .  
         [0060]    According to an aspect of the present invention, the inflation/deflation line could be removed and an air and suction feature inherent to endoscope  50  used to inflate and deflate the sheath respectively.  
         [0061]    According to an aspect of the present invention, markings may be provided so as to be viewable using endoscope  50 . According to an aspect of the present invention, reference points for determining a distance that the endoscope is withdrawn for treatment may take the form of markings at the distal end of the air/water/suction line  12  within the region of the balloon  104 , inner sheath  32  or outer sheath  34 , for example. This would allow the user to directly view how far back endoscope  50  is moved.  
         [0062]    According to an aspect of the present invention, it may be desirable to at least partially inflate balloon  104  to improve viewing through window  40 .  
         [0063]    Although the aforementioned describes preferred embodiments of the invention, the invention is not so restricted. It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed preferred embodiments of the present invention without departing from the scope or spirit of the invention. For example, although the invention was described as being used in a esophagus, it could be used in any biological cavity sized to receive an endoscope (e.g., bladder, colon, etc.). In addition, although the invention was described as treating Barrett&#39;s Esophagus, it could be used to treat or diagnose other diseases or ailments such as colon or bladder cancer.  
         [0064]    According to an aspect of the present invention, fiber  60  may be replaced by, or supplemented with, another medical treatment device or apparatus. By way of nonlimiting example, one or more ultrasound applicators could be sheathed by apparatus  10  so as to permit treatment, or the application of a procedure, to tissue via a cavity in which apparatus  10  has been inserted.  
         [0065]    Accordingly, it should be understood that the apparatus and method described herein are illustrative only and are not limiting upon the scope of the invention, which is indicated by the following claims. Accordingly, alternatives which would be clear to one of ordinary skill in the art upon reading the teachings herein disclosed, are hereby within the scope of this invention.