Patent Publication Number: US-2023148845-A1

Title: Vivo visualization system

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of prior U.S. Application Ser. No. 10/914,411, filed Aug. 9, 2004. This application also claims the benefit of U.S. Provisional Application No. 60/555,356, filed Mar. 23, 2004, and U.S. Provisional Application No. 60/656,801, filed Feb. 25, 2005. All of the aforementioned applications are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the present invention generally relate to medical devices. Several embodiments are generally directed to medical catheters with steering and/or optical capabilities. Other embodiments are generally related to medical systems, such as in-vivo visualization systems, that are suitable for viewing and/or performing diagnostic and therapeutic modalities within the human body, such as in the biliary tree. 
     BACKGROUND OF THE INVENTION 
     A challenge in the exploration and treatment of internal areas of the human anatomy has been adequately visualizing the area of concern. Visualization can be especially troublesome in minimally invasive procedures in which small diameter, elongate instruments, such as catheters or endoscopes, are navigated through natural passageways of a patient to an area of concern either in the passageway or in an organ reachable through the passageway. 
     Ureteroscopy is one form of procedure that is performed to diagnosis and treat urinary tract diseases and ureteral strictures. In conventional ureteroscopy, a ureteroscope is inserted retrograde through the urinary tract such that diagnosis and treatment of urinary tract abnormalities occur under direct visualization. Ureteroscopes are typically 7-10Fr. in diameter and include a sheath that encapsulates a fiber optic element, an illumination element and a working channel. The working channel allows for the passage of working devices, such as guidewires, stone retrieval baskets and lasers. Some ureteroscopes also incorporate a steering mechanism, which allows the distal tip of the scope to be deflected by the user in one or more planes. Steering is typically achieved via manipulation at the handle end of the scope, ex-vivo. 
     Problems, however, exist in the use of prior art ureteroscopes. For example, after each successive urological procedure, the scope must be cleaned and sterilized before the next use, which delays successive procedures unless multiple scopes are purchased. Furthermore, current ureteroscopes are non-disposable and require extensive, expensive maintenance. Sterilization delays and costs associated with purchasing and/or repairing scopes have escalated costs for ureteroscopic procedures and other medical procedures that utilize similarly configured scopes. 
     Detailed information regarding other parts of the anatomy can be discerned from direct viewing of the anatomy provided through one or more of the elongate instruments used in other various medical procedures, such as colonoscopy, upper endoscopy, bronchoscopy, thoracoscopy, laparoscopy, and hysteroscopy. For use in these procedures, various types of endoscopes configured for use in various passageways of the body, such as the esophagus, rectum or bronchus, can be equipped with direct viewing capability through the use of optical fibers extending through the length of the scope, or with digital sensors, such as CCD or CMOS. However, because endoscopes also provide a working channel through which other medical instruments must pass, optional lighting bundles and components to provide steering capability at its distal end, the scope is typically of a relatively large diameter, e.g., 5 mm or greater. This large diameter limits the use of the endoscope to relatively large body lumens and prohibits their use in smaller ducts and organs that branch from a large body lumen, such as the biliary tree. 
     Typically when examining small passageway such as the bile duct or pancreatic duct, the endoscope is used to get close to a smaller passageway or region of concern and another instrument, such as a catheter, is then extended through the working channel of the endoscope and into the smaller passageway. Although the endoscope provides direct visualization of the large body passageway and entrance to adjoining ducts and lumens, after the smaller catheter has been extended from the endoscope into the smaller duct or lumen, direct visualization has heretofore been limited, and the physician usually relies on radiographical means to visualize the area of concern or probes blindly. 
     SUMMARY OF THE INVENTION 
     In accordance with aspects of the present invention, a medical visualization system is provided. The system includes an endoscope having an endoscope insertion tube extending distally from an endoscope handle. The endoscope handle has an access port for accessing an interior lumen of the insertion tube. The endoscope includes an imaging device for viewing objects located at the distal end of the insertion tube. The system also includes a catheter assembly comprising a catheter extending distally from a catheter handle. The catheter handle is selectively mounted to the endoscope and has an access port for accessing an interior lumen of the catheter, wherein the catheter may be inserted into the endoscope access port and routed through a portion of the insertion tube interior lumen. The system further includes an optical assembly comprising an image transmission cable having distal and proximal ends, wherein the image transmission cable is configured for insertion into the catheter access port and routable through a portion of the catheter interior lumen. The optical assembly is capable of obtaining images located at the distal end of the catheter and transmitting the images to the proximal end of the cable. 
     In accordance with another aspect of the present invention, a medical visualization system is provided. The system includes a disposable catheter having a proximal end and a distal end. The catheter defines one or more interior lumens that extend from the distal end to the proximal end. The system further includes a control handle including an actuation device that effects distal end catheter deflection. The control handle is functionally connected to the proximal end of the catheter. The system further includes a reusable optical assembly that includes an optical handle and an optical cable extending therefrom. The optical cable is routable through a portion of the interior catheter lumen from a position exterior to the catheter. 
     In accordance with another aspect of the present invention, a catheter handle is provided. The catheter handle is suitable for steering a catheter shaft having a proximal region and a distal region and at least one steering wire having a distal end region secured at or near the distal end region of the catheter shaft and a proximal end. The catheter handle includes a catheter housing having the proximal end of the catheter shaft attached thereto and a steering controller carried by the catheter housing and having the proximal end of the at least one steering wire connected thereto. The steering controller is movable from a first position to a second position. The steering controller is capable of applying tension to the at least one steering wire when the steering controller moves from the first position to the second position. The catheter handle further includes a lock mechanism for retaining the steering controller in the second position to prevent movement thereof. The lock mechanism includes a lever movable between an unlocked position and a locked position. The lever is associated with the steering controller such that movement of the lever to the locked position restricts movement of the steering controller. 
     In accordance with aspects of the present invention, a method of bifurcating the interior lumens of a catheter for connection to one or more fittings is provided. The method includes obtaining a connector having a central passageway and first and second branch passageway connected thereto, obtaining a catheter having first and second interior lumens extending longitudinally therethrough, and forming first and second openings in the outer surface of the catheter at selected, spaced locations for accessing the first and second interior lumens. The location of the first and second openings correspond to the intersections of the first and second branch passageways with the center passageway of the connector, respectively. The method further includes routing the catheter into the central passageway until the first and second openings communicate with the first and second branch passageways, respectively. 
     In accordance with another aspect of the present invention, a method of examining a patient in-vivo is provided. The method includes providing an endoscope with an insertion tube having at least one channel. The endoscope has viewing capabilities at the distal end of the insertion tube. The method also includes providing a catheter having at least one channel, providing an imaging device having an image transmission cable, and advancing the insertion tube into a passageway of a patient under direct visualization by the insertion tube. The method further includes advancing the catheter through the insertion tube to a position at or near the distal end of the insertion tube; and advancing the image transmission cable through the catheter channel to a position at of near the distal end of the catheter. 
     In accordance with another aspect of the present invention, a method is provided for cannulating the papilla of a patient. The method includes providing an optical device having viewing capabilities, providing an endoscope with viewing capabilities and at least one channel, and providing a catheter having at least one channel. The method also includes placing the distal end of the endoscope into the duodenum of a patient and adjacent to the papilla and inserting the catheter into the channel of the endoscope and routing the catheter to the distal end of the endoscope. The method further includes advancing the optical device through the catheter channel to the distal end of the catheter; and advancing the catheter and optical device from the endoscope and through the papilla under visual inspection of the endoscope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG.  1    is an assembly view of an optical catheter system according to one embodiment of the invention; 
         FIG.  2    is a perspective end view of the distal tip of the catheter illustrated in  FIG.  1   ; 
         FIG.  3    is perspective end view of the distal tip of the catheter illustrated in  FIG.  1   , where the sheath of the catheter has been removed to expose the elongated, internal body of the catheter; 
         FIG.  4    is a cross-sectional view of the elongated body of the catheter illustrated in  FIG.  3   , taken along the line  4 - 4  in  FIG.  3   ; 
         FIG.  5    is a cross-sectional view of an alternative embodiment of a catheter of the system illustrated in  FIG.  1   , where the cross-section is taken along a longitudinal axis of the catheter; 
         FIG.  6    is an assembly view of an optical catheter system according to another embodiment of the invention; 
         FIG.  7    is an assembly view of an optical catheter system according to a further embodiment of the invention; 
         FIG.  8    is a perspective view of one embodiment of a handle of the optical catheter system illustrated in  FIG.  7   ; 
         FIG.  9    is an assembly view of an optical catheter system according to another embodiment of the invention; 
         FIG.  10    is an assembly view of an optical catheter system according to a further embodiment of the invention; 
         FIG.  11    is an assembly view of an optical catheter system according to an additional embodiment of the invention; 
         FIG.  12 A  is a partial longitudinal cross section view of another embodiment of a catheter formed in accordance with aspects of the present invention; 
         FIG.  12 B  is a partial longitudinal cross section view of another embodiment of a catheter formed in accordance with aspects of the present invention; 
         FIG.  13 A  is a partial longitudinal cross section view of another embodiment of a catheter formed in accordance with aspects of the present invention; 
         FIG.  13 B  is a partial longitudinal cross section view of another embodiment of a catheter formed in accordance with aspects of the present invention; 
         FIG.  14 A  is a partial view of one suitable embodiment of a catheter body constructed in accordance with aspects of the present invention; 
         FIG.  14 B  is a partial view of one suitable embodiment of a catheter formed by taking the catheter body of  FIG.  14 A  and encasing said catheter body with a reinforcement sheath; 
         FIG.  14 C  is a partial view of one suitable embodiment of a catheter formed by taking the catheter of  FIG.  14 B  and encasing said catheter with an outer sleeve; 
         FIG.  15    is a cross sectional view of the catheter taken along lines  9 - 9  in  FIG.  14 B ; 
         FIG.  16    is a partial view of the distal end of another embodiment of a catheter that is suitable for used in the system illustrated in  FIG.  1   ; 
         FIG.  17    is a partial view of the distal end of another embodiment of a catheter that is suitable for used in the system illustrated in  FIG.  1   ; 
         FIG.  18    is a partial view of the distal end of another embodiment of a catheter that is suitable for used in the system illustrated in  FIG.  1   ; 
         FIG.  19 A  is a perspective view of one suitable embodiment of a catheter assembly suitable for use in an optical catheter assembly; 
         FIG.  19 B  is a top view of the catheter assembly shown in  FIG.  19 A ; 
         FIG.  19 C  is a perspective cross section view of the catheter assembly shown in  FIG.  19 A ; 
         FIG.  19 D  is a top cross section view of the catheter assembly shown in  FIG.  19 A ; 
         FIG.  20    is a planar view of one suitable embodiment of an optical assembly suitable for use in an optical catheter assembly; 
         FIG.  21    is a partial bottom view of the catheter assembly shown in  FIG.  19 A   
         FIG.  22    is a cross sectional view of the imaging device cable of  FIG.  20     FIG.  23 A  is a side view of the optical handle of  FIG.  20   ; 
         FIG.  23 B  is a side view of the optical handle of  FIG.  20    showing the detachable nature of its components; 
         FIG.  24    is a perspective view of another catheter handle formed in accordance with aspects of the present invention; 
         FIG.  25    is a top view of another catheter handle formed in accordance with aspects of the present invention; 
         FIG.  26    is a top view of another catheter handle formed in accordance with aspects of the present invention; 
         FIGS.  27 A- 27 B  are partial perspective views of a distal portion of one embodiment of a catheter formed in accordance with aspects of the present invention, several portions of  FIG.  27    is shown in cross-section; 
         FIG.  28    is a perspective view of one embodiment of a catheter distal end cap formed in accordance with aspects of the present invention; 
         FIG.  29    is a perspective view of another suitable embodiment of a catheter assembly suitable for use in an optical catheter assembly; 
         FIG.  30    is a cross-sectional view of another embodiment of a catheter that is suitable for use with the catheter assembly shown in  FIG.  19 A ; 
         FIG.  31    is a front elevational view of one representative embodiment of an in-vivo visualization system constructed in accordance with aspects of the present invention; 
         FIG.  32    is a lateral cross sectional view of an insertion tube of an endoscope shown in  FIG.  31   ; 
         FIG.  33    is a perspective view of one embodiment of a catheter assembly constructed in accordance with aspects of the present invention; 
         FIG.  34    is a perspective view of the catheter assembly shown in  FIG.  33    with one housing half removed; 
         FIGS.  35 A- 35 C  are cross sectional views of suitable embodiments of a catheter constructed in accordance with aspects of the present invention; 
         FIG.  36 A  is a partial view of one suitable embodiment of a catheter body constructed in accordance with aspects of the present invention; 
         FIG.  36 B  is a partial view of one suitable embodiment of a catheter formed by taking the catheter body of  FIG.  36 A  and encasing said catheter body with a reinforcement sheath; 
         FIG.  36 C  is a partial view of one suitable embodiment of a catheter formed by taking the catheter of  FIG.  36 B  and encasing said catheter with an outer sleeve; 
         FIG.  37    is a cross sectional view of the catheter taken along lines  39 - 39  in  FIG.  38 B ; 
         FIGS.  38 A- 38 C  are cross sectional views of suitable embodiments of a catheter constructed in accordance with aspects of the present invention; 
         FIGS.  39 A- 39 C  are cross sectional views of suitable embodiments of a catheter constructed in accordance with aspects of the present invention; 
         FIG.  40    is a partial perspective view of a catheter handle with the control knobs removed to illustrate a lock lever; 
         FIG.  41    is a partial cross sectional view of a catheter handle showing a suitable embodiment of an irrigation port connected to irrigation lumens of the catheter; 
         FIG.  42    is a partial cross section view of the catheter handle showing the steering mechanism and the optional locking mechanism; 
         FIG.  43 A  is a front exploded perspective view of components of the locking mechanism of  FIG.  42   ; 
         FIG.  43 B  is a rear exploded perspective view of components of the locking mechanism of  FIG.  42   ; 
         FIG.  44    is a partial perspective view of the catheter handle of  FIG.  41    illustrating a suitable embodiment of an endoscope attachment device; 
         FIG.  45    is a cross sectional view of one embodiment of a Y connector formed in accordance with the present invention when assembled with a catheter; 
         FIG.  46 A  is an end view of a distal end of another embodiment of a catheter formed in accordance with the present invention; 
         FIG.  46 B  is a partial side elevational view of the distal end of the catheter shown in  FIG.  46 A ; 
         FIG.  47    is an end view of another embodiment of a catheter formed in accordance with the present invention; and 
         FIG.  48    is an end view of another embodiment of a catheter formed in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments of the present invention will now be described with reference to the drawings where like numerals correspond to like elements. Embodiments of the present invention are directed to systems of the type broadly applicable to numerous medical applications in which it is desirable to insert one or more steerable or non-steerable imaging devices, catheters or similar devices into a body lumen or passageway. Specifically, several embodiments of the present invention are generally directed to medical visualization systems that comprise combinations of disposable and reusable components, such as catheters, functional handles, hubs, optical devices, etc. 
     Other embodiments of the present invention are generally directed to features and aspects of an in-vivo visualization system that comprises a catheter having a working channel through which a catheter having viewing capabilities is routed. As will be described in detail below, the catheter may obtain viewing capabilities by being constructed as a vision catheter or by having a fiberscope or other viewing device selectively routed through one of its channels. The catheter is preferably of the steerable type so that the distal end of the catheter may be steered from its proximal end as it is advanced within the body. A suitable use for the in-vivo visualization system includes but is not limited to diagnosis and/or treatment of the duodenum, and particularly the biliary tree. 
     Several embodiments of the present invention include medical devices, such as catheters, that incorporate endoscopic features, such as illumination and visualization capabilities, for endoscopically viewing anatomical structures within the body. As such, embodiments of the present invention can be used for a variety of different diagnostic and interventional procedures. Although exemplary embodiments of the present invention will be described hereinafter with reference to duodenoscopes, it will be appreciated that aspects of the present invention have wide application, and may be suitable for use with other endoscopes (e.g., ureteroscopes) or medical devices, such as catheters (e.g., guide catheters, electrode catheters, angioplasty catheters, etc.). Accordingly, the following descriptions and illustrations herein should be considered illustrative in nature, and thus, not limiting the scope of the present invention. Additionally, the catheter with vision capabilities may be utilized alone, as well as in conjunction with a conventional endoscope. 
       FIG.  1    illustrates an optical catheter system  8  in accordance with one embodiment of the present invention. The primary components of the system  8  include a sterile, single-use, disposable catheter  10 , a sterile, single-use, disposable hub  20 , and a reusable handle  30 . In the illustrated embodiment, the hub  20  is integral, i.e., permanently part of, the disposable catheter  10  such that they together define a sterile, single-use, disposable catheter assembly. For example, the hub  20  may be joined to the catheter  10  with injection molding or adhesive bonding. The catheter assembly defined by the hub  20  and catheter  10  is preferably packaged in a sterile container or package (not illustrated) prior to use by a physician. In an alternative embodiment, the hub  20  is integral, i.e., permanently part of, the handle  30 . In a further embodiment, the hub  20  is not integral with the catheter  10  or the handle  30 , but connects to these items with connectors, such as male and female threaded connectors, quick lock connectors, bayonet connectors, snap connectors, or other known connectors. 
     As is illustrated in  FIGS.  2 - 4   , the catheter  10  includes an elongated, preferably cylindrical, body  38  that extends the entire length of the catheter  10 . In one embodiment, the catheter body  38  has an outer diameter between approximately 5 and 12 French, and preferably between approximately 7 and 10 French. The catheter body  38  may be constructed from any suitable material, such as Pebax® (polyether block amides), nylon, polytetrafluoroethylene (PTFE), polyethylene, polyurethane, fluorinated ethylene propylene (FEP), thermoplastic elastomers and the like, or combinations thereof. The body  38  may be formed of a single material using known techniques in the art, such as extrusion, or multiple materials by joining multiple extruded sections by heat bonding, adhesive bonding, lamination or other known techniques (e.g., juxtaposed Nitinol tubes wrapped with an adhesive bonding. 
     In some applications, e.g. urological, it is desirable that the catheter  10  have a varying degree of stiffness from the distal (e.g., renal pelvis) end  18  towards the proximal (e.g., bladder) end  16 . The proximal end  16  should be stiff enough for the device to advance in the tract to the desired location (e.g., in the urinary tract to the renal pelvis/kidney area). The distal end  18  should be soft enough to provide a reduction in trauma during insertion but rigid enough to provide adequate support during the procedure and prevent collapse or kinking. According to an embodiment of the present invention for urological application, the distal portion of the catheter (approximately 1-2 inches where the flexing occurs) is made more flexible (i.e., less stiff) than the remainder of the catheter to allow for steerability of the catheter in vivo. Several techniques for constructing a catheter having a more flexible distal portion than the remainder of the catheter will be described in more detail below. 
     In the embodiment shown in  FIG.  1   , the catheter  10  includes a proximal portion  42  that extends the majority of the catheter  10  and a distal portion  44 . The catheter  10  preferably varies in stiffness between the proximal portion  42  and the distal portion  44 . More preferably, the proximal portion  42  is stiffer than the distal portion  44 . This allows the catheter  10  to be easily advanced without compressing and with minimal twisting while providing deflection capabilities to the distal portion  42  for deflecting the distal end  18 . In one embodiment, the proximal portion  42  has a durometer value between 35 and 85 shore D, preferable 60-80 shore D, and the distal portion  44  has a durometer value between 5 and 55 shore D, preferable 25-40 shore D. 
     As is illustrated in  FIGS.  2  and  3   , the catheter  10  may optionally include an inner sheath  56  and/or an outer sleeve  58  that encase the length of the elongated body  38  or portions thereof. In one embodiment, the sheath  56  is a woven or layered structure, such as a braided design of fine wire or polymeric elements woven or coiled together along the longitudinal axis of the catheter with conventional catheter braiding (e.g., 2 wires having a diameter ranging from 0.001 to 0.010 inches wound in a 2-over, 2-under helical fashion from the proximal to distal end of the catheter  10 ). This allows the catheter  10  to be advanced to the desired anatomical site by increasing the column strength of the assembly while also increasing the torsional rigidity of the catheter. Conventional coiled polymer or braid wire may also be used for this component with coil wire dimensions ranging in width from 0.002 to 0.120 inches and thickness from 0.002 to 0.10 inches. Braided ribbon wire (e.g., 0.002×0.005 inches; 0.003×0.012 inches) may also be used for the sheath  56 . 
     The outer sleeve  58  may comprise of any number of polymer jackets that are laminated over the first sheath  56 . Suitable materials for the sleeve  58  include, but without limitation, polyethylene, such as polyethylene having a molecular weight in the range of 50,000 to 100,000; nylon, such as nylon 12, nylon 4-6, and nylon 6-6; Pebax (polyether block amides); polyurethane; polytetrafluoroethylene (PTFE), particularly fluorinated ethylene propylene (FEP) copolymers; and polyethylene impregnated with PTFE. The outer sleeve  58  may be used to vary the stiffness of the catheter, if desired, or to provide improved torque transfer and/or other desirable catheter properties. Additionally, the sleeve  58  may be used as one convenient method for securing a more flexible deflection section to the proximal section, as will be described in detail below. In one embodiment, as will be described in more detail below, the outer sleeve  58  is coextruded, coated, or otherwise attached once the sheath  56  is applied, to lock the sheath  56  in place and secure it to the catheter body  38 , thereby forming a composite catheter. 
     In several embodiments, the external surface of the catheter, for example, the outer sleeve  58 , can have a hydrophilic coating or a silicone coating to ease the passage of the device in vivo. Such a hydrophilic coating can be, for example, but without limitation, N-Vinyl Pyrrolidone, Poly Vinyl Alcohol, and Poly Vinyl Pyrrolidone. The hydrophilic coating can be accomplished by coating the device with a primer, such as Bayhydrol 110 (an anionic dispersion of an aliphatic polyester urethane resin in water/n-methyl-2pyrrolidone) and then bonding a primary layer over the primer. The primary layer can be, without limitation, an acrylamide or a polyurethane-based acrylamide. Alliphatic polyether and polyester polyurethanes also can be used as lubricous coatings. 
     In a further embodiment, the distal portion  44  of the catheter  10  may contain a preset curve detail that allows a physician to easily access various locations (e.g., the renal pelvis) with minimal manipulation via passive deflection (i.e., without ex-vivo steering mechanism actuation). In one embodiment, the durometer of the sleeve  58  varies from 35 Shore D to 85 Shore D (preferably in the region of 70-80D) at the proximal end  16  to 20 Shore D to 55 Shore D (preferably in the region of 30-43D) at the distal end  18 . Curves of various shapes and geometries may be preset to the distal portion  44  of the catheter  10  as desired. For example, these curves may be pre-baked into the sleeve  58  at an elevated temperature below the melting point of the polymer. This pre-baked curve can vary between 10 and 270 degrees from vertical, depending upon the specific application of the system  8 . To insert the catheter  10 , the curve should be such that when a dilator or stiff guidewire is inserted into a working channel of the catheter  10  (described below), the curve is straight, while once the dilator or guidewire is removed, the distal portion  44  reverts to the pre-baked curve providing access to a desired location. In one embodiment, the distal portion  44  of the sleeve  58  has a radiopaque marker band  46  mounted thereon to provide confirmation of the location of the distal end  18  via fluoroscopy. 
     Referring now to  FIGS.  2 - 4   , the elongated body  38  of the catheter  10  defines a working channel  60  that extends the entire length of the catheter and allows for the passage of various treatment or diagnostic devices, such as guide wires, stone retrieval baskets, lasers, biopsy forceps etc. The working channel  60  preferably has a diameter sufficient to accept up to a 4 French working device, such as a retrieval basket device or biopsy forceps. The elongated body  38  of the catheter  10  may also include additional channels  62 , for use, e.g., as irrigation/insufflation channels or additional working channels for one or more of the instruments mentioned above. The channels  62  each extend the entire length of the catheter  10  and, like the working channel  60 , allow the passage of devices, liquids and/or gases to and from the treatment area. The channels  62  each have a diameter similar to or smaller than main working channel  60 . In one embodiment, the channels  62  each have a diameter of about 0.020 inches. The catheter may also include a channel  64  that extends the entire length of the catheter through which a fiberscope, fiber optic cables or other small diameter imaging devices (e.g., 0.25 mm-1.5 mm diameter) can be routed to the distal end of the catheter  10 . It will be appreciated that one or more of the channels  62  may be eliminated or dimensioned to accommodate the necessary diameter needed for the working channel  60  and optic lumen. 
     As is illustrated in  FIGS.  2 - 4   , the catheter  10  also includes a pair of control or steering wires  68  that cause a distal portion  44  of the catheter  10  to deflect in one or more directions as indicated by the dashed lines in  FIG.  1   . The steering wires  68  are located on opposite sides of the catheter  10  and slide within grooves  70  in opposite sides of the elongated body  38 . In other embodiments, the steering wires  68  may reside in the sheath  56  or outer sleeve  58 . In yet another embodiment, the steering wires  68  may be routed through dedicated steering wire lumens in the catheter. The steering wires  68  extend from the distal end  18  of the catheter  10  to the opposing, proximal end  16  of the catheter  10 , and then through the hub  20 . The steering wires  68  may be attached to the distal end  18  of the catheter  10  in a conventional manner, such as adhesive bonding, heat bonding, crimping, laser welding, resistance welding, soldering or other known techniques, at anchor points such that movement of the wires causes the distal end to deflect in a controllable manner. In one embodiment, the steering wires  68  are attached via welding or adhesive bonding to a fluoroscopy marker band  46  (see  FIG.  1   ) fixedly attached to the distal end. In one embodiment, the band may be held in place via adhesive and/or an outer sleeve, as will be described in more detail below. The steering wires  68  preferably have sufficient tensile strength and modulus of elasticity that they do not deform (elongate) during curved deflection. In one embodiment, the steering wires are made from 304 stainless steel with an 0.008 inch diameter and have a tensile strength of approximately 325 KPSI. The steering wires  68  can be housed in a PTFE thin-walled extrusion (not shown) to aid in lubricity and prevent the catheter  10  from binding up during deflections, if desired. 
     In the illustrated embodiment shown in  FIG.  1   , the steering wires  68  terminate in a wire connector  70 , which may also be part of the hub  20 . The wire connector  70  is a mechanical device that provides a detachable, preferably quick-fit, connection between the steering wires of the catheter  10  and the controller  74  or handle steering wires (not illustrated) associated with the handle  30 . Various types of detachable mechanical connectors, such as joints and linking elements, are capable of forming a connection that allows active deflection of the wires  68  via the controller  74  of the handle  30 . In the illustrated embodiment, the catheter  10  includes two steering wires  68  that controllably steer the catheter distal end  18  within one plane. In alternative embodiments, the catheter  10  includes additional wires that allow a user to steer the distal end  18  in multiple planes. In a further embodiment, the catheter  10  only includes one control wire that allows the user to steer the distal end  18  in one direction. In another embodiment, such as described below, the steering wires  68  are not part of the catheter  10 . In such an embodiment, the catheter can be advanced over a guidewire (not shown) pre-placed in the region of interest. 
     Referring now to  FIG.  5   , there is shown a cross-sectional view of an alternative embodiment of a catheter  510  suitable for use with the optical catheter system  8 . The catheter  510  illustrated in  FIG.  5    also includes additional features and inherent functions, as described further below. Unlike the catheter  10 , the catheter  510  has one large lumen  512  as opposed to multiple lumens. This is referred to as a “loose tube” configuration. The steering wires  568  run along the inner diameter of the catheter  510  to the distal end and are located within channels defined by an internal sleeve or liner  547 . The liner  547  has a low co-efficient of friction to facilitate the passage of working devices through the catheter during surgery. The liner  547  has a wall thickness from 0.0005 to 0.010 inches and is preferably formed from nitinol tubing, a polymer containing a degree of fluoroethylene such as, but not limited to, FEP, PTFE or PTFE impregnated thermoplastic elastomers like Pebax or is formed from a polymer having fluoroethylene combined with thermoplastic materials such as polyamides, polyurethane, polyethylene and block co-polymers thereof. The optical assembly, any working devices, and any irrigation tubes pass through the lumen  512  and connect with the hub as described above and below. In an alternative embodiment, the elongated body  538  of  FIGS.  2 - 4    passes through the lumen  512 , where the elongated body  538  routes any working devices, the optical assembly, and any irrigation tubes as described above. 
     The catheter  10  may be constructed in many different ways to achieve the desired result of a catheter having varying stiffness along its length, a few of which will now be described in more detail.  FIG.  12 A  is a longitudinal cross-section view of one embodiment of a catheter  1210  constructed in accordance with aspects of the present invention. As best shown in  FIG.  12 A , the catheter  1210  comprises a catheter body  1238  that is constructed with discrete proximal, deflection, and distal tip sections  1282 ,  1284 ,  1288 . In this embodiment, the proximal section  1282  is stiffer than the deflection section  1284 . Each section may be constructed in any suitable manner, such as extrusion or milling, with any suitable materials, such as polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), thermoplastic elastomers, chosen for the desired application. The sections  1282 ,  1284 , and  1288  are then coupled together to form an integral body by encasing the length of the body  1238  or portions thereof with an outer sleeve  1258 . The deflection section may contain one or both of section elements  1284  and  1288  to impart the required deflection at the distal end to the system. The outer sleeve  1258  may comprise one of any number of polymer jackets that are laminated, co-extruded, heat shrunk, adhesive bonded, or otherwise attached over the catheter body  1238 . Suitable materials for the sleeve  1258  include, but are not limited to, polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), and thermoplastic elastomers to name a few. It will be appreciated that the sections  1282 ,  1284 , and  1288  may also be heat bonded or adhesive bonded prior to outer sleeve attachment. 
     The catheter  1210  may optionally include an inner reinforcement sheath  1256 , for example, a metallic braid, disposed between sections  1282 ,  1284 , and  1288  of the elongated body  1238  and the outer sleeve  1258 , as best shown in  FIG.  12 B . The reinforcement sheath  1256  encases the length of the catheter body  1238  or portions thereof. In one embodiment, the reinforcement sheath extends from the proximal end of the catheter body to proximal an optional radio opaque band (not shown) at the distal tip section. The reinforcement sheath increases the kink resistance of the deflecting section  1284  to ensure that internal lumens remain patent during bending. 
       FIG.  13 A  is a longitudinal cross section view of another embodiment of a catheter  1310  constructed in accordance with aspects of the present invention. As best shown in  FIG.  13 A , the catheter  1310  defines a proximal section  1382 , a deflection section  1384 , and a distal tip section  1388 . The catheter  1310  comprises a catheter body  1338  and an outer sleeve  1358 . The catheter body  1338  is a unitary core that is formed, preferably by extrusion, with one suitable material, such as nylon, Pebax®, PTFE, etc. In one embodiment, the body  1338  is a PTFE extrusion. When assembled, the outer sleeve  1358  encases the length of the elongated body  1338  or portions thereof. The outer sleeve  1358  comprises a number of polymer jackets  1358 A,  1358 B, and  1358 C that are laminated, co-extruded, heat shrunk, adhesive bonded, or otherwise attached over sections  1382 ,  1384 , and  1388  respectively, of the catheter body  1338 . The stiffness value of each jacket is specifically selected to achieve the desired results, and may vary upon different catheter applications. 
     In one embodiment, the jacket  1358 A, which corresponds to the proximal section  1382 , is constructed of a material having a greater stiffness value than the jacket  1358 B, which corresponds to the deflection section  1384 . Suitable materials for the sleeve  1358  include, but are not limited to, polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), to name a few. If PTFE is chosen for the body  1338 , it may be necessary to etch or otherwise prepare its outer surface to promote suitable adhesion of the outer sleeve  1358 . 
     The catheter  1310  may optionally include an inner reinforcement sheath  1356 , for example, a metallic braid, disposed between the elongated body  1338  and the outer sleeve  1358 , as best shown in  FIG.  13 B . The reinforcement sheath encases the length of the elongated body  1338  or portions thereof. In one embodiment, the reinforcement sheath extends from the proximal end of the catheter body to proximal an optional radio opaque band (not shown) at the distal tip section. The reinforcement sheath increases the kink resistance of the deflecting section to ensure that internal lumens remain patent during bending. 
       FIGS.  14 A- 14 C and  15    illustrate another embodiment of a catheter  1410  constructed in accordance with aspects of the present invention. As best shown in  FIG.  14 A , the catheter includes a catheter body  1438  having a proximal section  1482 , a deflecting section  1484 , and a distal tip section  1488 . In one embodiment, the proximal section  1482  is constructed of a material that is stiffer than the deflecting section  1484 . The proximal section  1482  and the deflecting section  1484  may be extrusions constructed from any suitable material, such as polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), and thermoplastic elastomers, to name a few. In one preferred embodiment for urological application, the proximal section is a multi-lumen, PTFE extrusion approximately 200 to 220 cm in length, and the deflecting section  1484  is a multi-lumen, Pebax® extrusion approximately 2 to 10 cm in length. The deflection section  1484  may be coupled to the proximal section  1482  via suitable adhesive or joined by other techniques. The distal tip section  1488  may be coupled to the distal end of the deflection section  1484  via suitable adhesive. The distal tip section  1488  may be constructed of any suitable material, such as stainless steel or engineering plastics, including but not limited to polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), and thermoplastic elastomers. The catheter body  1438  may also include a radio opaque marker band  1446  that encircles a portion of the distal tip section  1488 . 
     The catheter  1410  (see  FIG.  14 B ) also includes a reinforcement sheath  1456  that extends from the proximal end of the catheter to or immediately proximal of the radio opaque marker band  1446 . The sheath  1456  may be a woven or layered structure, such as a braided design of fine wire or polymeric elements (0.001 inches to 0.010 inches in diameter) woven or coiled together along the longitudinal axis of the catheter with conventional catheter braiding techniques. This allows the catheter to be advanced to the desired anatomical site by increasing the column strength of the assembly while also increasing the torsional rigidity of the catheter. The reinforced catheter body shown in  FIG.  14 B  is then encased by an outer sleeve  1458  comprising of one or more sleeve sections  1458 A,  1458 B, and  1458 C, having the same or different stiffness values, as best shown in  FIG.  14 C , to form the catheter  1410 . 
     Returning to  FIG.  14 A , the catheter also includes a plurality of steering wires  1468  that extend through grooves or slots formed in the catheter body from the proximal end of the catheter past the deflecting section  1484 . In one embodiment, the steering wires  1468  terminate at the radio opaque marker band  1446  to which the steering wires  1468  are joined by adhesive bonding, laser welding, resistance welding, soldering or other known techniques. 
     In several embodiments, it is preferable for the steering wires to be encased with a laminate structure  1496  for allowing the steering wires  1468  to move freely within or along the catheter body, and thus, make the mechanics of actuation as smooth as possible. As best shown in  FIG.  15   , the laminate structure  1496  is formed by outer jacket  1497  constructed of a thermoplastic polymer, such as polyurethane, Pebax®, thermoplastic elastomer etc. which encases an inner reinforcement member  1498 , such as a metallic braid (e.g., stainless steel braid having, for example, a 0.0015″×0.006″ helically wound). Inside the reinforcement member  1498 , is a layer  1499  of a friction reducing material, such as PTFE or FEP tubing, over which the aforementioned layers are formed. The laminate structure  1496  begins at the proximal section  1482  and extends to just proximate the radio opaque marker band  1446 , as best shown in  FIG.  14 A . 
     As was described above, in several embodiments of the catheter, it is desirable for the deflection section or distal portion to be configured to deflect more easily than the proximal section or portion. In one embodiment, the deflection section or distal portion has a durometer value less than the proximal section. In other embodiments, the flexibility may be varied gradually (e.g., increasingly) throughout the length of a catheter tube from its proximal end to its distal end. In other embodiments, the deflection section may be an articulating joint. For example, the deflection section may include a plurality of segments that allow the distal section to deflect in one or more directions. For examples of articulation joints that may be practiced with the present invention, please see co-pending U.S. patent application Ser. Nos. 10/406,149, 10/811,781, and 10/956,007, the disclosures of which are hereby incorporated by reference. 
     Other mechanical joints or configurations may be utilized that allow the distal portion of the catheter to flex or bend in one or more directions more easily. Turning now to  FIG.  16   , there is shown one embodiment of a catheter  1610  formed in accordance with aspects of the present invention.  FIG.  16    shows a partial view of the distal portion  1646  of a catheter  1610  constructed from a metal or plastic tube with slots  1694  cut 180 degrees and spaced an even distance apart to form a deflecting section. The slots will allow the catheter  1610  to deflect in two directions or in a single plane at the distal end  1618 . The proximal section of the tube is not slotted and may be used as the non-deflecting portion of the catheter. If preferred, the slotted section may be used in embodiments discussed above. The slotted section can be useful when the catheter profile is not symmetrical or is irregular. It will be appreciated that the slots  1694  can be V-shaped, semi-circle, wave or any preferred configuration. 
       FIG.  17    illustrates another embodiment of a catheter  1710  having a deflectable distal portion. In this embodiment, the catheter is constructed from a very flexible plastic extrusion with multiple lumens. The two main lumens, the working channel  1760  and the optical assembly channel  1762 , are reinforced with coils  1796  to minimize out-of plane deflection. As shown in  FIG.  17   , the center of both lumens and both coils lie on the Y-axis to provide less resistance against deflection in the x-plane. When the steering wires (not shown) are pulled along the direction of the steering wire slots, the catheter will tend to bend about the y-axis or in the x plane. The coils  1796  also prevent the lumen from kinking as the catheter deflection radius becomes tighter. The catheter  1710  may further include an outer braid and outer layer, as described in detail above. 
       FIG.  18    illustrates yet another embodiment of a catheter  1810  having a flexible distal portion  1846 . In this embodiment, the multiple lumen extrusion is preferred to be flexible. Slots  1894  are cut on both sides of the extrusion to assist and bias the catheter  1810  in the preferred direction of deflection. As was described above, coils  1896  may be used to support the main lumens, if preferred, but are not required. The coil or coils can be useful if the slot cuts are deep to penetrate the main lumens. The coils could be used to line the lumens such that the devices do not inadvertently get caught against the slots. The catheter may further include a braided sheath and outer sleeve, as described above. 
     Returning now to  FIGS.  1 - 4   , the elongated body  38  of the catheter  10  includes a lumen  64  that holds an optical assembly  40  or portions thereof, as described briefly above. The optical assembly  40  is defined, e.g., by a cylindrical, elongated tubular member  24  and optic bundles  32 ,  34 . The optical assembly  40  permits a user of the system  8  to view objects at or near the distal end  18  of the catheter  10 . In the illustrated embodiment, the distal end  18  of the catheter includes a clear lens or window  22  that sealingly encloses the distal end of the lumen  64  to protect the optic bundles  32 ,  34  inside the lumen  16 . The member  24  defines multiple lumens  26  that each contain one fiber optic bundle  32 ,  34 . The first fiber optic bundle  32  illuminates the area or objects to be viewed, while the second fiber optic bundle  34  communicates the illuminated image to an eyepiece or ocular lens device  36  located at the handle  30  through which a user can view the images communicated via the fiber optic bundle. The handle  30  can also be configured to connect to a camera or imaging system such that users can save images and view them on a display. The fiber optic bundles  32 ,  34  each comprise one or more fiber optics cables, preferably multiple fiber optical cables, but may also include lenses, rods, mirrors, hollow or solid light guides, etc. The bundles  32 ,  34  are attached to the lens  22  with a clear adhesive, bond, or other connection, but can also abut the lens or be located adjacent the lens without any attachment. In an alternative embodiment, the lens  22  is not attached to the distal end  18  of the catheter, but is instead attached directly to the elongated member  24  and fiber optic bundles  32 ,  34 . 
     As will be appreciated, the optical components of the catheter  10  may take many other forms and configurations. For example, the lumen  64  can include one fiber optic bundle for communicating images and one or more single illumination fibers that are not fixed relative to each other by the elongated member  24 . That is, the fibers can be freely located in the lumen  64 . Additionally, the elongated member  24  can have more or less lumens  26  that contain more or less fibers and/or bundles for illuminating and/or communicating images. For example, in an alternative embodiment, a single fiber replaces one or both of the bundles  32 ,  34 . Furthermore, the elongated body  38  need not include the lumen  64 . For example, one or more optical fibers or bundles of fibers can be molded in the elongated body  38 . Alternatively, the elongated body  38  may include two lumens  64  for receiving separate fiber optic bundles  32  and  34 , respectively. Possible alternative known configurations for the optical assembly  40  are described in U.S. Pat. Nos. 4,782,819; 4,899,732; 5,456,245; 5,569,161; and 5,938,588, the entire disclosures of which are hereby incorporated by reference. 
     In the illustrated embodiment, the tubular optical assembly  40  is part of the disposable catheter assembly defined by the catheter  10  and hub  20 . Hence, the tubular optical assembly  40  and its fiber optic bundles  32 ,  34  extend from the distal end  18  of the catheter  10  to the opposing, proximal end  16  of the catheter  10 , and then through the hub  20 . As is illustrated in  FIG.  1   , the hub  20  includes a fiber optic connector  72  in which the fiber optic bundles  32 ,  34  terminate. The fiber optic connector  72  is a mechanical device that provides a detachable optical connection between the fiber of the optical assembly  40  and the fiber or lens system of the handle  30 . Thus, the optical assembly  40  extends continuously through the disposable catheter  10  and hub  20 , without interruption, to the fiber optic connector  72 . In one embodiment, the fiber optic connector  72  is a detachable, simple point-to-point connection or splice. In other embodiments, the connector  72  is a more complex design having multi-port or other types of optical connections. For example, the connector  72  can be configured to redistribute (combine or split) optical signals, such as with an active or passive fiber optic couplers, e.g., splitters, optical combiners, X couplers, star couplers, or tree couplers. The fiber optic connecter  72  can also include a micro lens, graded-refractive-index (GRIN) rods, beam splitters, and/or optical mixers, and may twist, fuse, and taper together the fiber optic bundles  32 ,  34 . In other embodiments, such as those described below, the optical assembly  40  is not part of the disposable catheter  10 . 
     Referring again to  FIG.  1   , the handle  30  is generally an endoscopic handle that connects to the connectors  70 ,  72  of the hub  20  such that a user of the system can view images communicated by the fibers of the catheter  10  and such that a user can controllably steer or deflect the distal end  18  of the catheter. The handle  30  includes one or more shafts  78  that connect to and interact with the fiber optic connector  72  and the wire connector  70 . The handle  30  also includes a controller or actuator  74  by which a user can steer the distal end  18  of the catheter  10 . In the illustrated embodiment, the handle  30  generally includes a pair of steering wires (not illustrated), each of which is associated with one of the steering wires  68  of the catheter  10 . The wires of the handle  30  are connected to the controller  74  at one end and are connected at the other end to the wires  68  via the connector  70 . To steer the catheter  10 , a user actuates the controller  74 , which causes the wires  68  to deflect, which in turn forces the distal end  18  of the catheter to deflect as illustrated in  FIG.  1   . In the illustrated embodiment, the controller  74  is a user-operated mechanical slide or rotatable lever that is adapted to pull and release the wires  68  connected to the handle  30  by the connector  70 . In an alternative embodiment, the controller  74  may take other forms, such as a rocker arm or rotating knob, adapted to pull and release the wires. In another alternative embodiment in which the catheter  10  has two or more pairs of steering wires, the handle  30  includes additional actuators and corresponding controls to drive the additional pairs of steering wires. In one embodiment, the handle  30  includes a locking mechanism, such that when a curve is activated by the controller  74 , the curve may be locked in place. The use of wires to steer a tip of a catheter is well-known. Suitable examples are set forth in U.S. Pat. Nos. 4,899,723; 5,273,535; 5,624,397; 5,938,588, 6,544,215, and International Publication No. WO 01/78825 A2, the entire disclosures of which are hereby incorporated by reference. 
     As is described above, the handle  30  includes steering wires and fiber optics that connect to the steering wires  68  and fiber optic bundles  32 ,  34  of the catheter  10  via the connectors  70 ,  72 . As will be appreciated, the handle  30  may be battery powered or connect to a power supply. The handle  30  also includes a light source, or connects to a light source, that illuminates the fiber bundle  32 . In addition, the handle  30  has an eyepiece  80  for a user to view an image transmitted by the image bundle  34  from the distal end  18 . 
     Referring again to  FIG.  1   , the hub  20  also includes connectors or ports  50  that each communicate with one of the lumens  62  of the catheter  10 , as well as a connector or port  52  that communicates with the working channel  60 . The connectors  50 ,  52  are preferably integral with the hub  20  and thus are disposable with the hub  20  and catheter  10 . In the illustrated embodiment, connector  72  is separate from the connector  70  and connects to two separate portions, shafts, or projections of the handle  30 . In an alternative embodiment, the connectors  70  and  72  are combined into a single connector that interfaces with a single portion of the handle  30 , such that the optics handle and actuator for steering are disconnectable as a unit and reusable. 
     In a further embodiment of a system  608  in which the connectors  670  and  672  are separate connectors, such as is illustrated in  FIG.  6   , the optical catheter system  608  includes a first handle  630 A that steers the catheter  610  and a second handle or component  630 B having the eyepiece  680  through which the user can view images communicated by the catheter optics. In this embodiment, the first handle  630 A connects to the connector  670  and the second handle  630 B connects to the connector  672  to couple and decouple from the fiber bundle in the catheter  610 . The handle  630 A may be disposable, while the handle  630 B is reusable. The handle  630 B includes a sleeve  682 , such as an extrusion over the fiber optic/illumination fiber component of the handle, to protect fiber sterility and prevent damage during the procedure due to the miniature nature of the fiber. 
     As will be appreciated from the foregoing, the optical catheter system  8  (See  FIG.  1   ) in accordance with one embodiment of the present invention includes a sterile, single-use, disposable optical catheter  10 , a sterile, single-use, disposable hub  20 , and a reusable handle  30  for viewing images and steering the catheter. Because the catheter  10  and hub  20  are disposed of after a procedure, delays and costs associated with cleaning, sterilizing, and maintaining conventional scopes are avoided. 
     Set forth below is a description of an exemplary clinical application of the optical catheter system  8  according to the invention. The sterile single-use catheter  10  and hub  20  are removed from a factory package and then connected to the reusable handle  30  via the connectors  70  and  72 . A guidewire is advanced into the urinary tract and the catheter  10  with or without a dilator is inserted over the guidewire. The guidewire may be withdrawn. The catheter  10  is then steered with the controller  74  to deflect the distal end  18  to the desired location in the kidney. The connectors/ports  50  and  52  are then associated with various working device and irrigation lines, as needed, and the desired treatment and/or diagnosis are performed. The catheter  10  is then withdrawn and discarded. 
     In an alternative embodiment of the optical catheter system  708  illustrated in  FIG.  7   , the optical assembly  740  is not attached to the distal end  718  of the catheter and instead extends from the distal end  718 , through the hub  720 , and into the handle  730  without interruption. Additionally, the steering wires  768  extend from the distal end  718 , through the hub  720 , and into the handle  730  without interruption. When fully inserted into the catheter  710 , the steering wires  768  each attach to the distal end  718  of the catheter  710  such that movement of the wires causes the distal end  718  to deflect in a controllable manner. The steering wires  768  attach to the distal end  718  of the catheter with a detachable connection (not shown), such as a snap or quick lock connection, that permits the steering wires to be easily detached from the distal end  718  after use of the catheter such that the wires can be withdrawn from the catheter. In this embodiment, the system  708  does not include the optical and wire connectors, and the wires  768  and optical assembly  740  are not disposable. That is, the wires  768  and optical assembly  740  are part of the reusable handle  730 . Hence, in this embodiment, the lumens and channels of the elongated body receive the elongated wires  768  and elongated optical assembly  740  of the reusable handle  730   b . The catheter  710  and hub  720  are still disposable. 
       FIG.  8    illustrates an alternative embodiment of a handle  830  suitable for use with an optical catheter system  8 . The handle  830  includes an optical portion  686  and a snap-on, slide-on, or clip-on steering portion  688 . The optical portion  686  is the same as that of the handle  30  (see  FIG.  1   ), but does not include the features for steering the catheter  10 . The steering portion  688  is the same as that of the handle  30  (see  FIG.  1   ), but does not include the optical features of the handle  30 . The steering portion  688  may be disposable or reusable. The optical portion  680  is reusable. 
     In a further embodiment of the optical catheter system  908  illustrated in  FIG.  9   , the connectors  970  and  972  are not part of the hub  920 , but are respectively attached to the optical assembly  940  and the steering wires  968 . The fibers of the optical assembly  940  are not attached to the distal end  918  of the catheter  910  and, when inserted into catheter, extend from the distal end  918 , through the hub  920 , and terminate at the connector  972 , which is integral with the optical assembly. The reusable handle  930  is configured to connect directly to the connector  972  of the optical assembly and functions as described above. When fully inserted into the catheter  910 , the steering wires  968  each attach to the distal end  918  of the catheter  910  such that movement of the wires causes the distal end  918  to deflect in a controllable manner. The steering wires  968  attach to the distal end  918  of the catheter with a detachable connection, such as a snap or quick lock connection, that permits the steering wires to be easily detached from the distal end  918  after use of the catheter such that the wires can be withdrawn from the catheter. When inserted into the catheter  910 , the wires  968  extend from the distal end  918 , through the hub  920 , and terminate at the connector  970 , which is integral with the wires. Hence, the wires  968  and the connector  970  form a control wire assembly. The handle  930  is configured to connect directly to the connector  970  of the steering wire assembly and function as described above. In this embodiment, the optical assembly  940  (and its connector  972 ) and the wires  968  (and their connector  970 ) are both disposable. The optical assembly  940  and its connector  972 , and the wires  968  and their connector  970  may be sterilely packaged separately or in combination with the catheter  910 . 
       FIG.  10    illustrates an additional embodiment of an optical catheter system  1008  of the present invention. In this embodiment, the handle  1030  for steering the catheter  1010  is integral with the hub  1020  and catheter  1010 , and are together packaged as a single-use, sterile, disposable assembly. The optical handle  1030 B and its optical assembly  1040  are reusable. Hence, the optical assembly  1040  is received by the hub  1020  and catheter  1010  for use, and then removed therefrom after the procedure has been performed. The steering wires of the handle  1030 A are attached to the distal end  1018  of the catheter  1010  and extend from the distal end  1018 , through the hub  1020 , and into the handle  1030 A without interruption. In this embodiment, the system  1008  does not include the optical fiber and steering wire connectors, and the optical assembly  1040  is part of, i.e., integral with, the reusable handle  1030 B. 
       FIG.  11    illustrates an additional embodiment of an optical catheter system  1108  of the present invention. In this embodiment, the handle  1030 A for steering the catheter  1110  is integral with the hub  1020  and catheter  1110 , and are together packaged as a single-use, sterile, disposable assembly. The optical handle  1030 B is reusable and is connectable to the disposable optical assembly  1140  via a connector  1172 . Hence, the optical assembly  1140  is disposable with the integral assembly defined by the handle  1130 A, the hub  1120 , and catheter  1110 , and may also be packaged with these items. The optical assembly  1140  is received by the hub  1120  and catheter  1110  for use, removed therefrom after the procedure has been performed, and then discarded with the handle  1130 A, the hub  1120 , and catheter  1110 . The optical handle  1130 B is reused. The steering wires of the handle  1130 A are attached to the distal end  1118  of the catheter and extend from the distal end  1118 , through the hub  1120 , and into the handle  1130 A without interruption. In this embodiment, the system  1108  does not include the steering wire connector, and the optical assembly  1140  is not integral with the reusable handle  1130 B. 
       FIGS.  19 A- 19 D and  20    illustrate another embodiment of an optical catheter system constructed in accordance with the present invention. As best shown in  FIGS.  19  and  20   , the optical catheter system includes a sterile, single-use, disposable catheter assembly  1912  (See  FIGS.  19 A- 19 D ) and a reusable optical system  2040  (See  FIG.  20   ). The catheter assembly  1912  includes a handle  1930 A and a catheter  1910 . The optical system  2040  includes an optical handle  2030 B connected to an optical cable  2042 . The optical handle  2030 B, in one embodiment, may comprise an image viewing device, such as an ocular  2080 , and a coupler  2084 . 
     As best shown in  FIG.  19   , the catheter  1910  is functionally connected to the catheter handle  1930 B. The catheter  1910  may be any suitable catheter for use in vivo, such as any one of the catheters described in detail herein. The handle  1930 A includes a handle housing  1932  to which a steering mechanism  1974 , optional lock mechanism  1976 , and one or more ports  1958 ,  1960  are operatively connected. In one embodiment, the handle housing  1932  comprises an upper, proximal section  1934  and a lower, distal hub  1936 . In the embodiment shown in  FIG.  19 A , the distal hub  1936  of the handle housing is Y-shaped. The Y-shaped hub  1936  includes a distal stem section  1938  to which the proximal end  1912  of the catheter  1910  is functionally connected. The Y-shaped hub  1936  further includes first and second branch sections  1940  and  1942 , the first branch section  1940  is connected to the distal end of the housing upper section  1934  while the second branch section  1942  includes an opening through which an interior channel of the catheter, such as the working channel, may be accessed. The first branch section  1940  may be connected to the upper section  1934  in such a manner as to permit free or limited rotation of the Y-shaped hub  1936  with respect to the housing upper section  1934  about a longitudinal axis of the handle  1930 A. In one embodiment, this may be accomplished by a circular flange (not shown) formed at the proximal end of the first branch section and being captured in a cooperating slot (not shown) formed by the distal end of the housing upper section. 
     In one embodiment, handle housing sections are formed by housing halves  1934 A and  1934 B and  1936 A and  1936 B joined by appropriate removable fasteners, such as screws, or non removable fastening techniques, such as heat bonding, ultrasonic welding or adhesive bonding. As best shown in  FIG.  19 A , the housing halves (only  1936 B is shown) of the Y-shaped hub  1936  define respective passageways  1948  and  1950  for communicating with the remainder of the handle housing  1934  and exterior the handle, respectively. The handle  1930 A further includes a bifurcation  1954 . The bifurcation  1954  is preferably insert molded to connect the proximal end  1916  of the catheter  1910  and its lumens to the working channel port  1958  and optical assembly port  1960 . In embodiments where the bifurcation  1954  is insert molded, the catheter steering wires  1968  are sleeved with a PTFE sleeve or a metal sleeve or similar coiled or braided tube such that molten polymer from the bifurcation process will bond to the sleeve and allow the steering wire within the sleeve to move respectively therein. 
     As was described above, the handle housing  1932  includes one or more ports  1958  and  1960  for providing access to the respective channels of the catheter  1910 . In the embodiment shown, the ports include, but are not limited to, a working channel port  1958  and an optical assembly port  1960 . The ports may be defined by any suitable structure. For example, the working channel port  1958  and the optical assembly port  1960  may be defined by fittings  1962  and  1964 , respectively, such as luer fittings, that may be bonded or otherwise secured to the handle housing  1932  when assembled. In one embodiment, the housing halves may define cooperating structure that securely locks the fittings  1962  and  1964  in place when assembled. The fitting  1962  and  1964  are connected to the appropriate catheter channels via tubing  1966 , as best shown in  FIG.  19 C . In one embodiment, the handle  1930 A also includes a loop hub  1970  interconnected between the optical assembly port  1960  and the tubing  1966 . The loop hub  1970  has an oversized chamber to allow the optical cable of the optical system to be deflected to account for the change (shortening) in catheter length when the distal end of the catheter is deflected by the steering wires  1968 . 
     The catheter handle  1930 A may also include a steering mechanism  1974 , as best shown in  FIGS.  19 A and  19 B . The steering mechanism  1974  of the catheter handle  1930 A controls the deflection of the distal end  1918  of the catheter  1910 . The steering mechanism  1974  may be any known or future developed mechanism that is capable of deflecting the distal end of the catheter by selectively pulling one or more steering wires  1968 . In the embodiment shown in  FIGS.  19 A and  19 B , the steering mechanism  1974  includes an activation lever  1980  for effecting 2-way steering of the catheter distal end in a single plane. By actuating the activation lever  1980  in one direction the distal end will deflect in one direction. Turning the activation lever  1980  in the other direction will deflect the catheter distal end in the opposite direction. It is preferred that the catheter distal end will travel in a single plane when sweeping from one direction to the other. The activation lever  1980  is connected to the distal end  1918  of the catheter  10  via steering wires  1968  (See  FIG.  19 C ), respectively, that extend through the catheter  1910 . While a manually actuated steering mechanism for effecting 2-way steering of the distal end is shown, it will be appreciated that a manually actuated steering mechanism that effects 4-way steering may be practiced with and is therefore considered to be within the scope of the present invention. 
     Referring now to  FIGS.  19 A- 19 D , there is shown one embodiment of the steering mechanism  1974  that may be practiced with the present invention. The steering mechanism  1974  includes the activation lever  1980  secured for rotation with a pulley  1982 . The pulley  1982  is rotatably supported by a boss  1984  integrally formed or otherwise positioned to extend into the interior of the handle housing  1932  in a fixed manner from the housing half  1934 B. The pulley  1982  is either integrally formed or keyed for rotation with the activation lever  1980 . The proximal ends of one pair of steering wires  1968  are connected to opposite sides of the pulley  1982  in a conventional manner. In the embodiment shown, the steering wires  1968  are placed into respective slots  1986  and secured thereto by suitable fasteners, such as set-screws  1988 . Each set-screw pinches the steering wires  1968  against the pulley  1982  to secure it in place. When assembled, the pulley  1982  provides control of the distal end  1918  of the catheter  1910  in two directions. In these embodiments, the catheter  1910  is straight in the neutral position. 
     It will be appreciated that the steering mechanism may be configured such that the direction of catheter deflection in both directions is either equal or such that preferential one side deflection is realized (e.g., 180 degree deflection in one direction vs. 90 degree deflection in the other, etc.). For equal directional deflection, the steering wires  1968  are of equal length when the catheter is in the neutral (i.e., straight or unbent) position and are attached to the pulley  1982  at positions located along an axis of the pulley that is perpendicular to the longitudinal axis of the catheter, as best shown in  FIG.  19 D . For unequal angles of deflection, the steering wires are not equivalent in length and the steering wires are attached to the pulley in other positions around the circumference thereof. As will be appreciated, the catheter side related to the side with the greater steering wire displacement will deflect to the greater angle. In embodiments where there is only a single deflection of the shaft required, a single pull wire system may be used. The steering wire maybe attached to the pulley at a position proximal the perpendicular axis of the pulley to maximize the full swing of the pulley. 
     In other embodiments, it is also understood that changes could be made to the design to achieve a mechanical advantage such as to increase the diameter of the pulley for a longer steering wire displacement length. Other configurations that achieve a mechanical advantage may also be used. For example, instead of the steering wires terminating at the pulley, the steering wires may be wrapped around pins positioned on the pulley and then anchored on the handle at points distal the pulley. In this case, the steering wires will displace up to twice its normal distance when compared to the device shown in  FIG.  19 D . This feature may be used for larger diameter catheter deflection where longer steering wire displacement is utilized. 
     As best shown in  FIGS.  19 A- 19 D , the handle  1930 A may further include a lock mechanism  1976  that functions to lock the catheter  1910  in a desired deflection position or apply tension on the pulley  1982  during use. The lock mechanism  1976  includes a tension knob  1988  that is actuatable between a locked position, selectively tensioned positions, and an unlocked position. As best shown in  FIG.  19 C , the tension knob  1988  is threaded onto a thread post  1990  extending from the activation lever  1980 . The thread post  1990  extends through the handle housing to allow the tension knob  1990  to be externally mounted. In use, by tightening the tension knob  1990  on the thread post  1990  against the handle housing  1932  will also bring the activation lever  1980  into contact with the other handle housing half. The user can adjust the tension of the activation lever  1980 , as desired, by rotation of the tension knob  1990 . Further tightening of the tension knob  1990  will prevent rotation of the activation lever  1980 , thereby locking the steering wires  1968  in place, and in turn, locking the deflected position of the catheter  1910 . 
     In accordance with another aspect of the present invention, it may be desirable to adjust the tensioning of the steering wires after the handle  1930 A has been assembled. Turning now to  FIG.  21   , there is shown a handle having a tension adjustment assembly  2188  accessible from exterior the housing through a window  2190 . The tension adjustment assembly includes an adjustment screw  2192  cooperatingly engaged with a stationary nut  2194 . The nut  2194  may be held stationary and non-rotatable, for example, via molded structure in the handle housing. When assembled, the steering wires  1968  are threaded through the longitudinal lumen of the adjustment screw  2192 . The adjustment screw  2192  is designed with teeth on the side of its head portion to allow a user to rotate the screw. Rotation of the screw to advance the adjustment screw  2192  in the direction of arrow A will increase steering wire tension while rotation of the screw for advancing the screw  2192  in the direction of arrow B will decrease tension on the steering wires  1968 . Proper tension will allow quicker response of the steering wire to actuation of the activation lever. 
     As was discussed briefly above, a small diameter viewing device, such as a fiberscope or other imaging device, may be slidably routed through one channel (e.g., optical assembly channel) of the catheter  1910  to the distal end thereof. The viewing device permits the user of the optical catheter assembly to view objects at or near the distal end or tip of the catheter  1910 . Turning now to  FIG.  20   , there is shown one suitable embodiment of a viewing device or optical assembly  2040  formed in accordance with aspects of the present invention. The optical assembly  2040  includes a fiber optic cable  2072  connected to an optical handle  2030 B comprising a coupler  2084  and an ocular or eyepiece  2080 . The fiber optic cable  2072  is defined, for example, by one or more optical fibers or bundles  2032  and  2034  encased by a cylindrical, elongated tubular sleeve  2076 , as best shown in  FIG.  22   . The outer diameter of the fiber optic cable  2072  is preferably between 0.4 mm and 1.2 mm, although other sizes may be used depending on its application and the lumen size of the catheter. The tubular sleeve  2076  of the fiber optic cable  2072  may be constructed of any suitable material, such as nylon, polyurethane, polyether block amides, just to name a few. Additionally, a metallic hyptotube may be used. 
     In the illustrated embodiment, as best shown in  FIGS.  20  and  22   , the fiber optic cable  2072  includes one or more centrally extending coherent imaging fibers or fiber bundles  2034  and one or more circumferentially extending illumination fibers or fiber bundles  2032  (which may not be coherent) that generally surround the one or more imaging fibers of fiber bundles  2034 . The fibers or fiber bundles  2032  and  2034  may be attached to the tubular sleeve  2076  via suitable adhesive. The distal end of the fiber optic cable  2072  includes a distal lens and/or window (not shown) that encloses the distal end to protect the fiber bundles. Alternatively, the optical assembly lumen of the catheter  1910  (See  FIG.  19   ) may include a lens or window positioned at its distal end, as was described in detail above. The distal lens (not shown) also projects the image from the field of view onto the distal end of the image bundle  2034 . The image bundle  2034  then transmits the image from the distal end of cable  2072  to the handle  2030 B. 
     The optical assembly  2040  may have a stop collar or sleeve (not shown) to limit movement of the cable  2072  through the optical assembly channel of the catheter and limit the length by which the cable  2072  can extend beyond the distal end of the catheter  1910 . The inner surface of the imaging channel of the catheter may have color markings or other calibration means to indicate to the user when inserting the cable  2072  that the end of the catheter is approaching or has been reached. 
     The proximal end of the fiber optic cable  2072  is functionally connected to the coupler  2084  of the handle  2030 B. In use, the illumination fibers or fiber bundles  2032  illuminate the area or objects to be viewed, while the imaging fibers or fiber bundles  2034  communicates the illuminated image to an image viewing device, such as an eyepiece or ocular lens device  2080 , connected to the coupler  2084  through which a user can view the images communicated via the imaging fibers or fiber bundles  2034 . The eyepiece  2080  may either be permanently or detachably connected to the coupler  2084  as shown in  FIGS.  23 A and  23 B . In one embodiment, the eyepiece  2080  is detachably connected via a snap fit connector  2098 ; however, other selectively detachable connectors may be used, such as male and female threaded connectors, quick lock connectors, bayonet connectors, to name a few. In this embodiment, the coupler  2084  and cable  2072  can be detached from the eyepiece  2080  after a procedure and discarded, while the eyepiece  2080  may be sterilized and reused. The optical handle  2030 B can also be configured to connect to a camera or imaging system such that users can save images and view them on display. It will be appreciated that the handle  2030 B may include other known components, such as adjustment knobs (not shown), that adjust the relative positioning of the lenses and, thus, adjusts the focus of the image transmitted through them. The coupler  2084  may also includes a light post  2086  that is connected to the proximal end of the illumination fibers or fiber bundle  2032 . The light post  2086  is configured to be releasably connected to a light cable for supplying light from a light source external the optical assembly  2040  to the illumination fibers or fiber bundle  2032 . 
     In one embodiment, the optical assembly may optionally include a contamination sleeve  2090  for protecting fiber sterility and preventing damage during the procedure due to the miniature nature of the fiber, as best shown in  FIG.  20   . The contamination sleeve  2090  when attached to the handle extends from the coupler  2084  distally to a section of the optical cable  2072 . The end of the contamination sleeve  2090  terminates in a distal connector  2092 . The distal connector  2092  is configured to connect to the optical assembly port of the steering handle  1930 A, preferably in a sealable manner. 
       FIG.  24    illustrates another embodiment of a catheter handle  2430  constructed in accordance with aspects of the present invention that is suitable for use with the catheter  1910  described above and shown in  FIG.  19 A . The catheter handle  2430  is substantially similar in construction, materials, and operation as the catheter handle  1930 A described above and shown in  FIGS.  19 A- 19 D , except for the differences that will now be described. As best shown in  FIG.  24   , the distal hub section  2436  of the handle housing  2432  is not formed as a Y-shaped distal hub but instead is formed as a tapering cylindrical body. In this embodiment, both working channel and optical channel ports/luer connectors  2458 - 2460  are located at the proximal end of the handle housing  2432 . The connectors  2458  and  2460  are connected in communication with the respective catheter channels via tubes (not shown). Since the Y-shaped distal hub is not required in this embodiment, the entire handle housing can be formed by two molded housing halves. 
       FIG.  25    illustrates another embodiment of a catheter handle  2530  constructed in accordance with aspects of the present invention that is suitable for use with the catheter  1910  of  FIG.  19 A . The catheter handle  2530  is substantially similar in construction, materials, and operation as the catheter handle described above and shown in  FIGS.  19 A- 19 D , except for the differences that will now be described. The catheter handle  2530  shown in  FIG.  25    includes the coupler  2584  and optical cable (not shown) of the optical assembly  2540 , the coupler  2584  being slid, snapped into, molded, or otherwise mounted onto or within the handle  2530 . The components of the optical assembly  2540  are substantially similar in construction, materials, and operation as the components of the optical assembly described in  FIGS.  20  and  23 A,  23 B . The light post  2588  may be included with the coupler  2584  and may be located in a recessed fitting at the rear of the handle. The working channel port  2558  is shown to be side mounted and distal to the activation lever  2580 . In this embodiment, an ocular (not shown) can be removably attached to the coupler  2584  for direct viewing if a monitor is not available or connected to a monitor if preferred. 
       FIG.  26    illustrates another embodiment of a catheter handle  2630  constructed in accordance with aspects of the present invention that is suitable for use with the catheter  1910  described above and shown in  FIG.  19 A . The catheter handle  2630  is substantially similar in construction, materials, and operation as the catheter handle  1930  described above and shown in  FIGS.  19 A- 19 D , except for the differences that will now be described. As best shown in  FIG.  26   , the proximal portion  2690  of the handle  2630  has been lengthened such that the handle can be gripped at either the distal and proximal portions to manipulate the activation lever  2680  with the thumb or other finger of the user. It is desirable that sufficient distance exist between the working channel port  2658  and the handle activation lever  2680 , so that the user can comfortable hold the handle without blocking access to the working channel port for device feed. The optic assembly hub  2660  is not shown but can be positioned at the proximal handle end or exiting another side port at the Y-connector. It will be appreciated that the distal portion  2692  can be shortened such that the user uses and holds the proximal end only. Further, it will be appreciated that additional ports and hubs can be added, removed or repositioned as desired. 
     In accordance with another aspect of the present invention, it may be desirable to the user to provide a way to detect the orientation of the optical catheter assembly once in vivo. To that end,  FIGS.  27 A and  27 B  illustrate one suitable technique for indicating the orientation of optical catheter assembly when routed to a site within the patient. As best shown in  FIG.  27 A , an indicator, such as a marker  2764 , is placed on the optical cable  2772  of optical assembly  2740  to indicate a relative position, e.g., left side of the optical catheter assembly, when assembled with the catheter to aid the user in orientation and manipulation of the system. For illustration proposes only, the selected marking is shown in  FIG.  27 A  at the distal end of the optic fiber cable  2772  and oriented coplanar with the deflection of the catheter distal end as indicated by arrows A-A. In this embodiment, an insert  2770 , such as a metallic insert, is positioned at the distal end of the catheter optical assembly lumen and may be locked into place when the distal end of the catheter is formed. The insert  2770  is formed with the back end angle cut  2774  oriented to the plane of deflection. The cable sleeve  2776  is also configured to have a matching front end angle cut  2778  so that when meshed, the marker  2764  is oriented to indicate the desired position on the image transmitted to the handle. The meshed cuts  2774 ,  2778  also perform an anti-rotation function, that is, the cable  2772  is not allowed to rotate with respect to the catheter  2710  once meshed, as shown in  FIG.  27 B . The cable  2772  in this embodiment is made slightly longer than the catheter  2710  such that the cable deflects slightly in the loop hub chamber (see  FIG.  19 C ) when mated to create a constant force against the insert  2770 . It will be appreciated that other angles, geometries, keyways, etc. may be used to inhibit rotation of the cable with respect to the catheter and to orient the indicator in the specified location. 
     In operation, when the distal end of the catheter is deflected, the lumen length of the catheter becomes shorter due to the radius of the deflection curve. The insert  2770  prevents the cable  2772  from extending any further beyond the catheter distal end. The cable length is displaced by means of the fiber deflecting in the loop hub. As the catheter is straightened, the viscoelastic properties of the cable  2772  allows it to relax to the center of the loop hub, while still maintaining its position and contact with the insert  2770  at the distal end. 
       FIG.  28    illustrates a distal end cap  2896  that may be practiced with one of the catheters described above. A hole  2858  through the cap for the working channel is the same or larger than the working lumen of the catheter body. The distal hole  2560  in the cap for the optic fiber is size slightly smaller than the optical cable, establishing a stop mechanism for preventing the cable from exiting the cap yet providing a ledge for the cable to constantly abut against. The cable in this embodiment is made slightly longer than the catheter. The distal cap  2876  includes tapered sides  2898  to minimize the cross sectional area of the catheter distal end for reducing trauma when advanced in-vivo. 
       FIG.  29    illustrates another embodiment of a catheter assembly  2912  where a balloon  2914  is mounted on the catheter  2910  at or near the distal end  2918  with an accompanying inflation/deflation port  2962  at the proximal end of the handle. It will be appreciated that different types of balloons can be used for occlusion, dilatation, anchoring, or stabilizing yet still allow the working channel to remain patent for other uses. Other embodiments may include side ports for injections or suction. Other features may also be included, including an additional working channel as well as elevators, etc. Complex curve deflection can also be achieved as well as four or multiple way deflections. 
       FIG.  30    illustrates a cross section of another embodiment of a catheter  3010 . In this embodiment, it may be desired due to economies of manufacture and in the interests of reducing the overall outer diameter of the catheter to split the elements of the optical cable. As best shown in  FIG.  30   , there is shown a multi-lumen catheter having separate lumens  3062 A and  3062 B to house the illumination and image fiber bundles  3032  and  3034 , respectively. By separating both optic cable components in this way, a reduced catheter outer diameter may be realized. 
     It will be appreciated that the optical catheter system in the various embodiments described above could be used in other applications, such as a colonoscope, bronchoscope, gastroscope or similar visual device. Additionally, various modifications to the configurations, such as the number and dimension of working/optic channels, the length of the catheter, the materials used in construction, etc., may be made to accommodate the specific application without departing from the spirit of the invention. 
       FIG.  31    illustrates one exemplary embodiment of an in-vivo visualization system  3120  constructed in accordance with the present invention. The visualization system  3120  includes an endoscope  3124 , such as a duodenoscope, to which a steerable catheter assembly  3128  is operatively connected. As will be described in more detail below, the steerable catheter assembly  3128  includes a catheter  3130  and a catheter handle  3132 . The assembly  3128  may further include a viewing device  2040 , such as a fiberscope (See  FIGS.  20  and  23 A- 23 B ), or other small imaging device that is routed through a channel of the catheter  3130  for viewing objects at the distal end thereof. While the illustrative embodiments described below will reference the catheter  3130  and the handle  3132 , other suitable catheters, catheter handles, and combinations thereof may be utilized in the visualization system  3120 , such as those catheters and catheter/optical handles described above with regard to  FIGS.  1 - 30   . 
     In one suitable use, the endoscope  3124  is first navigated down the esophagus of a patient and advanced through the stomach and into the duodenum to the approximate location of the entrance to the common bile duct (also known as the papilla). After positioning the endoscope  3124  adjacent the common bile duct entrance, the catheter  3130  of the catheter assembly  3128  is advanced past the distal end of the endoscope  3124  and into the common bile duct entrance. Alternatively, the catheter  3130  may be routed prior to endoscope insertion. Once inside the common bile duct, the fiberscope allows a physician to view tissue in the bile duct, pancreatic duct and/or intrahepatics for diagnosis and/or treatment. 
     As best shown in  FIG.  31   , one suitable embodiment of an endoscope  3124  includes an endoscope handle  3140  and an insertion tube  3142 . The insertion tube  3142  is an elongated flexible body that extends from the distal end of the endoscope handle  3140 . In one embodiment, the insertion tube  3142  includes an articulation section  3144  disposed at its distal region, and a distal tip  3146 . The insertion tube  3142  is constructed of well known materials, such as polyether block amides (e.g., Pebax®), polyurethane, polytetrafluoroethylene (PTFE), nylon, to name a few. 
     As best shown in the cross sectional view of  FIG.  32   , the insertion tube  3142  defines a working channel  3150  that extends the entire length thereof and allows for the passage of various treatment or diagnostic devices, such as guide wires, biopsy forceps, and the steerable catheter  3130  ( FIG.  31   ). The insertion tube  3142  also includes one or more lumens for the purpose of facilitating the insertion and extraction of fluids, gases, and/or additional medical devices into and out of the body. For example, the insertion tube  3142  may include an irrigation and/or insufflation lumen  3152  and an optional suction lumen  3154 . The insertion tube  3142  further includes one or more lumens for the purpose of providing endoscopic viewing procedures. For example, the insertion tube  3142  includes one or more lumens  3156  that extend the entire length of the catheter and allows for light and optical fiber bundles  3158  and  3160  to be routed to the distal end thereof. Alternatively, the insertion tube  3142  may include one or more LED&#39;s and an image sensor, such as a CCD or CMOS, for capturing images at the distal tip and transmitting them to the endoscope handle  3140 . Finally, the insertion tube  3142  includes at least one pair of steering wires  3162 A and  3162 B, and preferably two pairs of steering wires  3162 A,  3162 B and  3164 A,  3164 B that are connected at the insertion tube&#39;s distal tip and terminate through the proximal end of the insertion tube  3142 . It will be appreciated that the insertion tube  3142  may include other features not shown but well known in the art. 
     Returning to  FIG.  31   , the proximal end of the insertion tube  3142  is functionally connected to the distal end of the endoscope handle  3140 . At the proximal end of the endoscope handle  3140 , there is provided an ocular  3166  through which a user can view the images communicated by the optical fiber bundle  3160  (See  FIG.  32   ), and a light cable  3168  for connecting to an external source of light. While the endoscope shown in  FIG.  31    includes an ocular, the endoscope may be of the electronic type, in which the ocular may be omitted and the images obtained from the distal end of the endoscope are transmitted to a video processor via the light cable  3168  or other suitable transmission means, and displayed by a suitable display device, such as a LED monitor. Light from the light source can be transmitted to the distal end of the insertion tube  3142  via the light fiber bundle  3158 . The endoscope handle  3140  also includes a steering mechanism  3170 , as shown in the form of control knobs, that are connected to the steering wires  3162 A,  3162 B, and  3164 A,  3164 B (see  FIG.  32   ) in a conventional manner for deflecting the distal end of the insertion tube  3142  in one or more directions. The endoscope handle  3140  further includes a biopsy port  3172  connected in communication with the working channel of the insertion tube  3142  for providing access to the working channel of the insertion tube  3142  from a position exterior the endoscope handle  3140 . 
     The in-vivo visualization system  3120  further includes the steerable catheter assembly  3128  which will now be described in more detail. As best shown in  FIGS.  33  and  34   , one suitable embodiment of the catheter assembly  3128  includes a catheter handle  3132  from which the catheter  3130  extends. The catheter  3130  includes an elongated, preferably cylindrical, catheter body  3176  that extends the entire length of the catheter  3130  from the catheter proximal end  3178  to the catheter distal end  3180 . In one embodiment, the catheter body  3176  has an outer diameter between approximately 5 and 12 French, and preferably between approximately 7 and 10 French. The catheter body  3176  may be constructed from any suitable material, such as Pebax® (polyether block amides), nylon, polytetrafluoroethylene (PTFE), polyethylene, polyurethane, fluorinated ethylene propylene (FEP), thermoplastic elastomers and the like, or combinations thereof. The body  3176  may be formed of a single material using known techniques in the art, such as extrusion, or multiple materials by joining multiple extruded sections by heat bonding, adhesive bonding, lamination or other known techniques. According to a preferred embodiment of the present invention, the distal portion of the catheter (approximately 1-2 inches where the flexing occurs) is made more flexible (i.e., less stiff) than the remainder of the catheter. 
     In the embodiment shown in  FIG.  33   , the catheter body  3176  includes a proximal section  3182  that extends the majority of the catheter  3130 , a deflection section  3184 , and a distal tip section  3188 . The catheter  3130  preferably varies in stiffness between the proximal section and the distal tip section. More preferably, the proximal section  3182  is stiffer than the deflection section  3184 . This allows the catheter to be easily advanced without compressing and with minimal twisting while providing deflection capabilities to the deflection section  3184  for deflecting the distal end  3180 . In one embodiment, the proximal section  3182  has a durometer value between 35 and 85 shore D, preferable 60-80 shore D, and the deflection section  3184  has a durometer value between 5 and 55 shore D, preferable 25-40 shore D. 
       FIG.  35 A  is a cross sectional view of one embodiment of the catheter body  3176 . The catheter body  3176  defines a working channel  3192  that extends the length of the catheter and allows for the passage of various treatment or diagnostic devices, such as guide wires, stone retrieval baskets, lasers, biopsy forceps etc. In one embodiment, the working channel  3192  preferably has a diameter sufficient to accept up to a 4-French working device, such as biopsy forceps. The catheter body  3176  may also include a channel  3194  that extends the entire length of the catheter through which a fiberscope, fiber optic cable, optical assembly or other small diameter viewing device (e.g., 0.25 mm-1.5 mm diameter) can be routed to the distal end of the catheter  3130 . The catheter body  3176  may further include additional channels  3196 ,  3198  for use, e.g., as irrigation channels or additional working channels. The channels  3196 ,  3198  each extend the entire length of the catheter and, like the working channel  3192 , allow the passage of devices, liquids and/or gases to and from the treatment area. These channels  3196 ,  3198  each have a diameter similar to or smaller than the main working channel, and may be symmetrically positioned to balance the remaining channels during extrusion. Such positioning of the channels balances out the wall thickness and stiffness in two transverse directions. Finally, the catheter body  3176  may include one or more steering wire lumens  3200  that extend the entire length of the catheter. 
     Referring to  FIGS.  33  and  35 A , the catheter  3130  further includes one or more steering wires  3204  that cause the distal end  3180  of the catheter  3130  to deflect in one or more directions. The steering wires  3204  are routed through a corresponding number of steering wire lumens  3200 , extend from the distal end  3180  of the catheter  3130  to the opposing, proximal end  3182  of the catheter  3130 , and terminate in a suitable manner with the steering mechanism, as will be described in detail below. The steering wires  3204  may be attached to the distal tip section  3188  of the catheter  3130  in a conventional manner, such as adhesive bonding, heat bonding, crimping, laser welding, resistance welding, soldering or other known techniques, at anchor points such that movement of the wires causes the distal end  3180  to deflect in a controllable manner. In one embodiment, the steering wires  3204  are attached via welding or adhesive bonding to a fluoroscopy marker band (not shown) fixedly attached to the distal tip section. In one embodiment, the band may be held in place via adhesive and/or an outer sleeve, as will be described in more detail below. The steering wires  3204  preferably have sufficient tensile strength and modulus of elasticity that they do not deform (elongate) during curved deflection. In one embodiment, the steering wires are made from 304 stainless steel with an 0.008 inch diameter and have a tensile strength of approximately 325 KPSI. The steering wires  3204  can be housed in a PTFE thin-walled extrusion (not shown) to aid in lubricity and prevent the catheter  3130  from binding up during deflections, if desired. 
     In the illustrated embodiment shown in  FIG.  35 A , the catheter  3130  includes two pairs of steering wires  3204  that controllably steer the catheter  3130  in two perpendicular planes. In alternative embodiments, the catheter  3130  includes one pair of steering wires  3204  that allow the user to steer the distal tip in one plane. In one embodiment, two steering wires may be provided and are located on opposite sides of the catheter  3130  and slide within grooves, as opposed to steering wire lumens  3200 , formed in the elongated body  3176  or either the sheath or outer sleeve, if included, as will be described in more detail below. In a further embodiment, the catheter  3130  only includes one steering wire  3204  that allows the user to steer the distal tip in one direction. In another embodiment, the steering wires may be omitted, and thus, the catheter  3130  can be of a non-steerable type. In such an embodiment, the catheter can be advanced over a guidewire (not shown) pre-placed in the bile or pancreatic duct. 
     In one embodiment, the catheter  3130  may also include an outer sleeve  3208  that encases the length of the elongated body  3176 , as shown in cross section in  FIG.  35 B , or sections thereof. The outer sleeve  3208  may comprise one of any number of polymer jackets that are laminated, co-extruded, heat shrunk, adhesive bonded, or otherwise attached over the catheter body  3176 . Suitable materials for the sleeve  3208  include, but are not limited to, polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), thermoplastic elastomers to name a few. The outer sleeve  3208  may be used to vary the stiffness of the catheter, if desired, or to provide improved torque transfer and/or other desirable catheter properties. Additionally, the sleeve  3208  may be used as one convenient method for securing a more flexible deflection section to the proximal section, as will be described in detail below. In several embodiments, the external surface of the sleeve  3208  may have a hydrophilic coating or a silicon coating to ease the passage of the device in-vivo, as was described in detail above with reference to  FIGS.  2 - 4   . 
     In other embodiments, the catheter  3130  may optionally include an inner reinforcement sheath  3210  disposed between the elongated body  3176  and the outer sleeve  3208 . The reinforcement sheath encases the length of the elongated body  3176  or portions thereof, as shown in  FIG.  35 C . The sheath  3210  may be a woven or layered structure, such as a braided design of fine wire or polymeric elements (0.001 inches to 0.010 inches in diameter) woven or coiled together along the longitudinal axis of the catheter with conventional catheter braiding techniques. This allows the catheter to be advanced to the desired anatomical site by increasing the column strength of the assembly while also increasing the torsional rigidity of the catheter. Conventional coiled polymer or braid wire may also be used for this component with coil wire dimensioning ranging in width from 0.002 to 0.120 inches and thicknesses from 0.002 to 0.10 inches. Braided ribbon wire may also be used for the sheath. In one embodiment, as will be described in more detail below, the outer sleeve  3208  is coextruded, coated, or otherwise attached once the reinforcement layer  3210  is applied, to lock the reinforcement layer in place and secure it to the catheter body  3176 , thereby forming a composite catheter. 
     The catheter may be constructed in many different ways to achieve the desired result of a catheter having varying stiffness along its length. For example, the catheter may be constructed in a substantially similar manner to the catheters described above with reference to  FIGS.  12 A- 18   . 
       FIGS.  36 A- 36 C, and  37    illustrates one suitable embodiment of a catheter  3630  constructed in accordance with aspects of the present invention that may be used with the visualization system described above. As best shown in  FIG.  36 A , the catheter includes a catheter body  3676  having a proximal section  3682 , a deflecting section  3684 , and a distal tip section  3686 . In one embodiment, the proximal section  3682  is constructed of a material that is stiffer than the deflecting section  3684 . The proximal section  3682  and the deflecting section  3684  may be extrusions constructed from any suitable material, such as polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), and thermoplastic elastomers, to name a few. In one preferred embodiment, the proximal section is a multi-lumen, PTFE extrusion approximately 200 to 220 cm in length, and the deflecting section  3684  is a multi-lumen, Pebax® extrusion approximately 2 to 10 cm in length. The deflection section  3684  may be coupled to the proximal section  3682  via suitable adhesive or joined by other techniques. The distal tip section  3686  may be coupled to the distal end of the deflection section  3684  via suitable adhesive. The distal tip section  3686  may be constructed of any suitable material, such as stainless steel or engineering plastics, including but not limited to polyethylene, nylon, Pebax® (polyether block amides), polyurethane, polytetrafluoroethylene (PTFE), and thermoplastic elastomers. The catheter body  3676  may also include a radio opaque marker band  3692  that encircles a portion of the distal tip section  3686 . 
     The catheter  3630  (see  FIG.  36 B ) also includes a reinforcement sheath  3688  that extends from the proximal end of the catheter to or immediately proximal of the radio opaque marker band  3692 . The sheath  3688  may be a woven or layered structure, such as a braided design of fine wire or polymeric elements (0.001 inches to 0.010 inches in diameter) woven or coiled together along the longitudinal axis of the catheter with conventional catheter braiding techniques. This allows the catheter to be advanced to the desired anatomical site by increasing the column strength of the assembly while also increasing the torsional rigidity of the catheter. The reinforced catheter body shown in  FIG.  36 B  is then encased by an outer sleeve  3690  comprising of one or more sleeve sections  3690 A,  3690 B, and  3690 C, having the same or different stiffness values, as best shown in  FIG.  36 C , to form the catheter  3630 . 
     Returning to  FIG.  36 A , the catheter also includes a plurality of steering wires  3694  that extend through channels of the catheter body from the proximal end of the catheter past the deflecting section  3684 . In one embodiment, the steering wires  3694  terminate at the radio opaque marker band  3694  to which the steering wires  3694  are joined by adhesive bonding, laser welding, resistance welding, soldering or other known techniques. In this embodiment, the catheter body includes openings  3695  formed in the outer surface thereof just proximal the radio opaque marker band  3694  via any suitable method, such as skiving. These openings  3695  communicate with the steering wire channels so that the steering wires  3694  may exit the extruded catheter body and connect to the radio opaque marker band  3694 , as shown. 
     In some instances where the catheter body is not extruded or otherwise constructed of PTFE or other friction reducing materials, it may be desirable to encase the steering wires  3694  with a laminate structure  3696  for allowing the steering wires  3694  to move freely within the catheter body, and in particular, the deflecting section  3684 , and thus, make the mechanics of actuation as smooth as possible. As best shown in  FIG.  37   , the laminate structure  3696  is formed by outer jacket  3697  constructed of a thermoplastic polymer, such as polyurethane, Pebax®, thermoplastic elastomer etc. which encases an inner reinforcement member  3698 , such as a metallic braid (e.g., stainless steel braid having, for example, a 0.0015″×0.006″ helically wound). Inside the reinforcement member  3698 , is a layer  3699  of a friction reducing material, such as PTFE or FEP tubing, over which the aforementioned layers are formed. In embodiments where the proximal section  3682  is extruded or otherwise formed with a friction reducing material, the laminate structure  3696  begins at the intersection of the proximal section  3682  and the deflecting section  3684  and extends to just proximate the radio opaque marker band  3694 , as best shown in  FIG.  36 A . 
     In accordance with one embodiment of the present invention, the multi-lumen catheters described herein may be extruded using known materials, such as PTFE, Nylon, Pebax®, to name a few. The catheters may be extruded using mandrels. In several embodiments of the present invention, the mandrels may be constructed from suitable materials, such as stainless steel, stainless steel with PTFE coating, or a phenol plastic, such as Cellcore®. In the embodiment shown in  FIG.  35 A , the multi-lumen catheter  3130  has eight lumens that include a working channel  3192 , a fiberscope or viewing device channel  3194 , and four smaller steering wire lumens  3200  spaced 90 degrees apart. To balance out the wall thicknesses and stiffnesses in the traverse directions during extrusion, left and right lumens  3196 ,  3198  may also be formed using separate mandrels. These lumens  3196 ,  3198  may be used for air/gas irrigation and insufflation. 
     The catheter  3130  shown in  FIG.  35 B  may optionally include an outer sleeve  3208 . The sleeve may be constructed of suitable materials by coextrusion, heatshrinking processes, such as reflow, or spray coating. The outer sleeve  3208  may provide additional rigidity, improved torque transfer, etc. In one embodiment, the outer sleeve may be applied for facilitating the attachment of a flexible distal section, such as a deflection section, that has a lower durometer value than the remaining catheter body. In such an embodiment, one suitable material that may be used includes, but is not limited to, Pebax® (polyether block amide). In other embodiments, the catheter  3130  may include a reinforcement layer  3210  or sheath between the catheter body  3176  and the outer sleeve  3208 , as best shown in  FIG.  35 C . The reinforcement may be any known catheter reinforcement structure, such as wire coil or braid. In such as embodiment, the outer sleeve  3208  is coextruded, coated, or otherwise attached once the reinforcement layer  3210  is applied, to lock the reinforcement layer in place. It will be appreciated that the reinforcement layer  3210  may extend the entire length of the catheter or portions thereof. In one embodiment, the reinforcement layer  3210  extends over the deflection section. It will be appreciated that if the body is extruded from PTFE, its outer surface should be etched or otherwise prepared for appropriate bonding with the outer layer. In accordance with another embodiment, the catheter may be built up using a catheter core  3820 , an optional reinforcement layer  3824 , and an outer sheath or jacket  3826 , as best shown in  FIGS.  38 A- 38 C . The catheter core  3820  is an open-lumen core that is extruded from suitable materials, such as nylon, PTFE, Pebax®, etc., with the use of mandrels. In this embodiment, the mandrels (not shown) are placed and configured to produced a plurality of open-lumens  3892 ,  3894 ,  3896 ,  3898 , and  3899  when extruded. The mandrels may be constructed from metal, Cellcore®, or PTFE. Once the open-lumen core has been extruded, the mandrels are kept in place and the core is either coextruded to add the outer sleeve  3826 , as shown in  FIG.  38 B , or braided and coextruded to add a reinforcement layer  3824  and an outer sleeve  3826 , as shown best in  FIG.  38 C . As was discussed above, the outer sleeve  3826  may function to lock the braid in place and/or to facilitate attachment of a distal section, such as a deflection section, having, for example, a lower stiffness value, if desired. 
     The mandrels (not shown) can then be removed after coextrusion. In one embodiment, the mandrels are constructed of a phenol plastic, such as Cellcore®. To remove these mandrels, the mandrels are pulled from one or both ends. Due to the “necking down” effect inherent to the Cellcore® material, the cross sectional areas of the mandrels decrease when pulled in tension, thereby allowing the mandrels to be removed from the built-up catheter. In one embodiment, this property of Cellcore® may be used to the manufacture&#39;s advantage by using such a material for the steering wire lumen mandrels. However, instead of completely removing the mandrels from the steering wire lumens, tension forces may be applied to the steering wire mandrels, and the mandrels may be drawn to a decreased diameter that will be sufficient to function as the steering wires. Thus, to be used as steering wires, the drawn mandrels are then connected to the distal end of the catheter in a conventional manner. While the latter embodiment was described as being coextruded to form the outer sheath, the outer sheath may be formed on the catheter core by a heat shrink process or spraycoating. 
     It will be appreciated that not all of the lumens in the latter embodiments need to be formed as open-lumens. Thus, as best shown in  FIG.  39 A- 39 C , only the steering wire lumens  3999  are formed as open-lumens. This will create over sized lumens for the steering wires and provided the largest possible lumen diameters for the lumens  3992 ,  3994 ,  3996 , and  3998 . 
     As was described above, in several embodiments of the catheter, it is desirable for the deflection section to be configured to deflect more easily than the proximal section. In one embodiment, the deflection section has a durometer value less than the proximal section. In other embodiments, the flexibility may be varied gradually (e.g., increasingly) throughout the length of a catheter tube from its proximal end to its distal end. In other embodiments, the deflection section may be an articulating joint. For example, the deflection section may include a plurality of segments that allow the distal section to deflect in one or more directions. For examples of articulation joints that may be practiced with the present invention, please see co-pending U.S. patent application Ser. Nos. 10/406,149, 10/811,781, and 10/956,007, the disclosures of which are hereby incorporated by reference. Other methods that my be used were described above with reference to  FIGS.  16 - 18   . 
     Returning to  FIGS.  33  and  34   , the catheter  3130  is functionally connected to the catheter handle  3132 . The handle  3132  includes a handle housing  3220  to which a steering mechanism  3224 , one or more ports  3226 ,  3228 ,  3230 , and an endoscope attachment device  3234  is operatively connected. In one embodiment, the handle housing  3220  is formed by two housing halves  3220 A and  3220 B joined by appropriate removable fasteners, such as screws, or non removable fasteners, such as riveting, snaps, heat bonding or adhesive bonding. In the embodiment shown, the proximal end of the catheter  3130  is routed through a strain relief fitting  3238  secured at the distal end of the handle housing  3220  and terminates at a Y connector  3242 , as best shown in  FIGS.  34  and  45   . The Y connector  3242  may be secured to the handle housing  3220  via any suitable means, such as adhesive bonding. Similarly, the proximal end of the catheter  3130  is securely coupled to the Y connector  3242  via suitable means known in the art, such as adhesive bonding. The Y connector  3242  includes first and second branch fittings  3244  and  3246  that define respective passageways  3248  and  3250  for communicating with the catheter working channel and the catheter imaging device channel, respectively, through openings  3251  and  3252  located on the outer surface of the catheter, as best shown in  FIG.  45   . 
     In embodiments of the present invention, the openings  3251  and  3252  may be formed by skiving the outer surface of the catheter. This process may be done manually using known mechanical techniques, or may be accomplished by laser micro-machining that removes a localized area of material from the outer surface of the catheter to expose one or more catheter channels. When assembled, the proximal ends of the catheter channels are plugged by adhesive or the proximal end of the catheter is capped to prohibit access to the channels. 
     As was described above, the handle housing  3220  includes one or more ports  3226 ,  3228 ,  3230  for providing access the respective channels of the catheter  3130 . In the embodiment shown, the ports include, but are not limited to, a working channel port  3226 , an imaging device port  3228 , and an irrigation/suction port  3230 . The ports may be defined by any suitable structure. For example, the working channel port  3226  and the imaging device port  3228  may be defined by fittings  3254  and  3256 , respectively, that may be bonded or otherwise secured to the handle housing  3220  when assembled. In one embodiment, the housing halves may define cooperating structure that securely locks the fittings  3254  and  3256  in place when assembled. With regard to the irrigation/suction port  3230 , a luer style fitting  3258  is preferably used for defining the port  3230 . The fitting  3258  defines a passageway  3260  for fluidly connecting the port  3230  with the appropriate catheter channels, as best shown in  FIG.  41   . The fitting  3258  works in conjunction with a barrel connector  3264  that ensconces the catheter  3130 . The barrel connector  3264  defines a cavity  3266  that surrounds the perimeter of the catheter  3130  and is fluidly connected to the appropriate catheter channels (irrigation channels) via inlets  3270 . As such, the port  3230  is connected in fluid communication with the irrigation channel via passageway  3260  and cavity  3266 . In one embodiment, the inlets  3270  are formed by skiving the outer surface of the catheter. This process may be done manually using known mechanical techniques, or may be accomplished by laser micro-machining that removes a localized area of material from the outer surface of the catheter to expose one or more catheter channels. The working channel port  3226  and the imaging device port  3228  are connected in communication with the branch fittings  3254  and  3256  of the Y connector, respectively, via appropriate tubing  3272 , and best shown in  FIG.  34   . 
     The catheter handle  3132  also includes a steering mechanism  3224 . The steering mechanism  3224  of the catheter handle  3132  controls deflection of the distal end  3180  of the catheter  3130 . The steering mechanism  3224  may be any known or future developed mechanism that is capable of deflecting the distal end of the catheter by selectively pulling the steering wires. In the embodiment shown in  FIGS.  33  and  34   , the steering mechanism  3224  includes two rotatable knobs for effecting 4-way steering of the catheter distal end in the up/down direction and in the right/left direction. This mechanism  3224  includes an outer knob  3280  to control up/down steering and an inner knob  3284  to control right/left steering. Alternatively, the inner knob  3284  may function to control right/left steering and an outer knob  3280  may function to control up/down steering. The knobs are connected to the distal end of the catheter  3130  via the steering wires  3204 , respectively, that extend through the catheter  3130 . While a manually actuated steering mechanism for effecting 4-way steering of the distal is shown, it will be appreciated that a manually actuated steering mechanism that effects 2-way steering may be practiced with and is therefore considered to be within the scope of the present invention. 
     Referring now to  FIG.  42   , there is shown one embodiment of the steering mechanism  3224  that may be practiced with the present invention. The steering mechanism  3224  includes inner and outer pulleys  3288  and  3290 , and control knobs  3280  and  3284 . The inner pulley  3288  for left and right bending control is mounted via an inner bore  3294  for rotation on a shaft  3296  integrally formed or otherwise positioned to extend into the interior of the handle housing  3220  in a fixed manner from the housing half  3220 A. The inner pulley  3288  is integrally formed or keyed for rotation with one end of an inner rotary shaft  3300 . The opposite end of the inner rotary shaft  3300  extends outside the handle housing  3220  to which the control knob  3280  is attached for co-rotation. In one embodiment, the end  3304  of the inner rotary shaft  3300  is configured to be keyed with a cooperatingly configured control knob opening. The control knob  3280  may then be retained thereon via a threaded fastener. The proximal end of one pair of steering wires  3204  are connected to opposite sides of the inner pulley  3288  in a conventional manner. 
     The outer pulley  3290  for up and down bending control is rotatably fitted over the inner rotary shaft  3300  for independent rotation with respect to the inner pulley  3288 . The outer pulley  3290  is integrally formed or keyed for rotation with one end of an outer rotary shaft  3310 . The outer rotary shaft  3310  is concentrically arranged in a rotational manner over the inner rotary shaft  3300 . The opposite end of the outer rotary shaft  3310  extends outside the handle housing  3220  to which the control knob  3284  is attached for co-rotation. The rotary shafts  3300 ,  3310  are further supported for rotation within the housing  3220  by a boss  3316  integrally formed or otherwise positioned to extend inwardly into the handle housing  3220  from the housing half  3220 B. It will be appreciated that other structure may be provided that rotatably supports the pulleys  3288 ,  3290  and shafts  3300 ,  3310  within the handle housing  3220 . When assembled, the proximal ends of the second pair of steering wires  3204  are fixedly connected in a conventional manner to the outer pulley  3290 , respectively. 
     In one embodiment, a thrust plate  3320  is positioned between the inner and outer pulleys  3288 ,  3290  for isolating rotary motion therebetween. The thrust plate  3320  is restricted from rotation when assembled within the housing  3220 . 
     The steering mechanism  3224  may further includes a lock mechanism  3340  that functions to lock the catheter  3130  in a desired deflection position during use. The lock mechanism  3340  includes a lever  3344  that is actuatable between a locked position and an unlocked position. In the embodiment shown in  FIG.  40   , detents  3346  are provided, and may be molded into the exterior housing half  3220 B to index the movement between the locked and unlocked positions. A small protuberance (not shown) may be included to signal the user that the lever  3344  has changed positions. 
     Referring now to  FIGS.  42 ,  43 A, and  43 B , the lock mechanism  3340  further includes a lever member  3350  and a pulley member  3354  that are housed within the handle housing  3220  when assembled. The lever member  3350  includes a throughbore  3358  that is size and configured for receiving the outer rotary shaft  3310  in a rotationally supporting manner. The lever member  3350  includes a boss section  3362  that is sized and configured to be rotationally supported by the inwardly extending boss  3316  when assembled. The boss section  3362  is configured at one end  3364  to be keyed for rotation with one end of the lock lever  3344 . The lever member  3350  further includes a flange  3366  integrally formed at the other side of the boss section  3362 . The end face  3368  of the flange  3366  defines a cam profile that annularly extends around the perimeter of the flange  3366 . In the embodiment shown, the cam profile is formed by varying the thickness of the flange. The pulley member  3354  includes a boss section  3370  that is sized and configured for receiving the lever member  3350  therein. The pulley member  3354  includes an inwardly extending flange  3374  that defines a cam profile on the lever member facing surface  3378  of the flange  3374 . Similar to the lever member  3350 , the cam profile of the pulley member  3354  is formed by varying the thickness of the flanges as it annularly extends. The inwardly extending flange  3374  further defines a throughbore  3380  that is sized and configured for receiving the outer rotary shaft  3310  in a rotationally supporting manner. When assembled, the pulley member  33254  is restricted from rotating with respect to the housing  3220  but allowed to linearly translate, as will be described in more detail below. 
     When assembled, the lever member  3350  is inserted within the pulley member  3354 , the cam profiles mate, and the lever  3344  is keyed for rotation to the lever member  3350 . The cam profiles on the lever member  3350  and the pulley member  3354  are specifically configured to transmit a rotary motion of the lever  3344  into translational movement of the pulley member  3354 . Thus, when the lever member  3350  rotates by movement of the lever  3344  from the unlocked position to the locked position, the pulley member  3354  moves away from the lever member  3350  in a linear manner by coaction of the cam profiles. Therefore, the lever member  3350  acts like a cam, and the pulley member  3354  acts like a follower to convert rotary motion of the lever  3344  into linear motion of the pulley member. The linear movement of the pulley member  3354  causes the inner pulley  3288  to frictionally engage the housing  3220  and the thrust plate  3320  while the outer pulley  3290  frictionally engages the thrust plate on one side and the pulley member of the other. The friction present between the engaged surfaces prohibits rotation of the inner and outer pulleys  3288  and  3290 , and thus, locks the distal end of the catheter in a deflected position. 
     To change the deflection of the distal end of the catheter from one position to another, the lock lever  3344  is moved from the locked position to the unlocked position. This, in turn, rotates the lever member  3350  with respect to the pulley member  3354 . Due to the configuration of the cam profiles of the lever and pulley members, the pulley member  3354  is capable of moving toward the lever member  3350 . This alleviates the friction between the engagement surfaces and allows the inner and outer pulleys  3288  and  3290  to rotates by turning the control knobs  3284  and  3280 . 
     In accordance with aspects of the present invention, the catheter assembly  3128  can be mounted directly to the endoscope handle  3140  so that a single user can manipulate both the endoscope  3124  and the catheter assembly  3128  using two hands. In the embodiment shown, the catheter handle  3132  is attached to the endoscope  3124  via the endoscope attachment device, such as the strap  3234 . The strap  3234  can be wrapped around the endoscope handle  3140 , as best shown in  FIG.  31   . The strap  3234  includes a number of notches  3366  into which the head of a housing projection  3368  is selectively inserted to couple the catheter handle to the endoscope, as best shown in  FIG.  44   . The strap  3234  allows the catheter handle  3132  to rotate around the shaft of the endoscope  3124 , if desired. The strap  3234  is positioned such that when used to attach the handle  3132  to the endoscope  3130 , the longitudinal axes of the both handles are substantially aligned, as shown best in  FIG.  31   . Additionally, the strap orientation and the location of the ports on the catheter handle  3132  allow for manipulation of diagnostic or treatment devices and viewing devices through the catheter without interfering with control and use of the endoscope. As a result of directly connecting the catheter assembly  3128  to the endoscope  3124 , as shown in  FIG.  31   , the catheter  3130  creates a loop, known as a service loop, prior to entrance into the biopsy port  3172 . In one embodiment, the catheter may include a proximally located stop sleeve or collar (not shown), which limits the minimum diameter of the service loop and the extension of the catheter  3130  beyond the distal end of the conventional endoscope. Alternatively, a mark or indicia may be placed on the catheter  3130  and used to prevent over insertion of the catheter  3130 . 
     In embodiments of the present invention that form a service loop by directly connected the catheter handle  3132  to the endoscope  3124 , the catheter  3130  is preferably constructed to be suitably longer than conventional catheters to compensate for the service loop. In several of these embodiments, the catheter handle  3132  is preferable mounted below the biopsy port  3172  of the endoscope  3124  and the catheter  3130  is preferably looped upward and into the biopsy port  3172 . In this configuration, the catheter  3130  is accessible and can be gripped by the user just above the biopsy port for catheter insertion, withdrawal, and/or rotation. 
     While the embodiment above shows a handle connected below the biopsy port and longitudinally oriented with respect to the catheter, other configurations are possible. For example, the handle can be attached to the endoscope so that the longitudinal axis of the catheter handle is substantially transverse to the longitudinal axis of the endoscope handle. Additionally, the catheter handle may be mounted proximally or distally of the biopsy port or may be mounted directly on the biopsy port so that the longitudinal axis of the catheter is coaxial with the biopsy port. 
     As was discussed briefly above, a small diameter viewing device, such as a fiberscope or other vision device, may be slidably routed through one channel (e.g., imaging device channel) of the catheter  3130  ( FIG.  33   ) to the distal end thereof. The viewing device permits the user of the catheter assembly to view objects at or near the distal end or tip of the catheter. For a detailed description of one viewing device that may be utilized by the visualization system, please see the optical assembly described above with regard to  FIGS.  20  and  23 A- 23 B . For other examples of imaging devices that may be practiced with embodiments of the present invention, please see the description of the fiber optic cable in co-pending U.S. application Ser. No. 10/914,411, filed Aug. 9, 2004 to which priority as been claimed, and the guidewire scope described in U.S. Published Patent Application Number 2004/0034311 A1, the disclosures of which are hereby incorporated by reference. 
     The imaging device  3370  may have a stop collar or sleeve (not shown) to limit movement of the cable  3372  through the imaging device channel of the endoscope and limit the length by which the cable  3372  can extend beyond the distal tip of the catheter  3130 . The inner surface of the imaging channel of the catheter may have color markings or other calibration means to indicate to the user when inserting the cable  3372  that the end of the catheter is approaching or has been reached. 
     One suitable method of operation of the in-vivo visualization system  3120  will now be described in detail with reference to the aforementioned FIGURES. The insertion tube  3142  of the endoscope  3124  is first navigated down the esophagus of a patient under endoscope visualization. The insertion tube  3142  of the endoscope  3124  is advanced through the stomach and into the duodenum at the bottom of the stomach. The biliary tree comprises the cystic duct from the gall bladder, the hepatic duct from the liver and the pancreatic duct from the pancreas. Each of these ducts joins into the common bile duct. The common bile duct intersects with the duodenum a slight distance below the stomach. The papilla controls the size of the opening at the intersection between the bile duct and duodenum. 
     The papilla must be crossed in order to reach the common bile duct to perform a biliary procedure. The insertion tube  3142  of the endoscope  3124  is navigated under direct visualization so that the exit port of the working channel  3150  is directly across from the papilla or so that the port is slightly below the papilla. After positioning the distal end of the insertion tube  3142  in the proper position, the catheter  3130  with the imaging device  3370  is advanced through the working channel  3150  the endoscope  3124  such that the distal end of the catheter  3130  emerges from the endoscope and cannulates the papilla. The endoscope  3124  provides viewing of the catheter  3130  as it emerges from the endoscope  3124  and is advanced to enter the papilla. After cannulating the papilla, the catheter  3130  may be advanced into the common bile duct. Once advanced into the common bile duct, the fiber optic cable  3372  of the viewing device  3370  located within the catheter  3130  allows a physician to view tissue in the bile duct for diagnosis and/or treatment. 
     Alternatively, once the insertion tube  3142  of the endoscope  3124  is in place next to the papilla, a conventional guidewire and sphinctertome may be advanced together through the endoscope and through the papilla to enter the common bile duct and pancreatic duct. It may be necessary for the physician to use the sphinctertome to enlarge the papilla. The sphinctertome may then be removed from the patient while leaving the conventional guidewire in place. The catheter  3130  and the fiber optic cable  3372  of the viewing device  3370  may then be advanced together over the conventional guidewire through the papilla and into the common bile duct. Once inside the common bile duct, the fiber optic cable  3372  of the viewing device  3370  allows a physician to view tissue in the bile duct for diagnosis and/or treatment. 
     It will be appreciated that the selection of materials and use of insertable and removable optics in the catheter allow for the catheter to be constructed as a single use device. Once the procedure is performed, the optics can be removed and sterilized for reuse while the catheter may be removed from the endoscope and discarded. 
     While the steerable catheter assembly  3128  has been described above for use with an endoscope, it will be appreciated that the catheter assembly may be used with other devices, or may be used as a stand-alone device or in conjunction with the viewing device  3370 . 
       FIGS.  46 A- 46 B  illustrates the distal end of an alternative embodiment of a catheter  4630  formed in accordance with aspects of the present invention. In this embodiment, the catheter  4630  has a multi-lumen design with one or more (shown as three) steering wire lumens  4640  around its perimeter. Steering wires (not shown) extend from the proximal end of the catheter to the distal region of the catheter and terminate in an anchored connection at or near the distal end thereof. Deflection of the distal end of the catheter may be effected by the steering wires in a manner well known in the art. The catheter  4630  includes other lumens, for example, a guide wire lumen  4660 , a working channel lumen  4662 , and a fiberscope or other viewing device lumen  4664 . As shown, the guide wire lumen  4660  is offset from the longitudinal axis of the catheter. 
     In use, the tip of the catheter is advanced beyond the end of the endoscope and is steered in the direction of the papilla. The guide wire is then advanced through the papilla and the catheter is advanced to cannulate the papilla. Once in the biliary tree, and with visualization provided via the fiberscope or other viewing device, the guide wire is advanced again and steered to the target site. The catheter is once more advanced over the guide wire and positioned for use of the accessory instruments at the therapy site while simultaneously viewing such site with the fiberscope. 
     In an alternative embodiment, instead of extruding the catheter body, a catheter  4730  may be constructed with an outer sheath  4758  encasing a bundle  4770  of smaller diameter tubes, as best shown in  FIG.  47   . Each tube of the bundle of tubes may be formed using any known technique, such as extrusion. Each tube extends the length of the catheter and may be used for a specific function, such as steering wire lumens, device working channel, optic channel, fluid or air infusion channel, or section channel, etc. Each tube is preferably separately constructed with materials specifically selected to maximize performance, lubricity, flexibility, and/or other desirable characteristics. When assembled, one or more steering wires  4774  are routed through a corresponding number of steering tubes  4776  of the catheter. The steering wires  4774  may be connected to the distal end of the catheter via adhesive, heat bonding, crimping, or other known techniques. In one embodiment, the steering wires may be attached to a radio opaque marker band  4780  for use in fluoroscopy. 
     Alternatively, as best shown in  FIG.  48   , a catheter  4830  may be formed from a steering sheath  4854 , such as a steering guide catheter of appropriate dimensions, by filling the central longitudinal lumen  4856  with a bundle of tubes. The steering sheath  4854  typically includes an outer sleeve or jacket  4858  with an internal sleeve or liner  4862 . The steering wires  4874  typically run along the inner surface of the catheter to the distal end and are located within channels  4877  defined by the internal sleeve or liner  4862 . The liner preferably has a low coefficient of friction to facilitate the passage of wires, and may be formed from a polymer containing PTFE or PTFE impregnated thermoplastic elastomers, or may be constructed of thermoplastic materials, such as polyamides, polyurethane, polyethylene, and block copolymers thereof. 
     The principles, preferred embodiments, and modes of operation of the present invention have been described in the foregoing description. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes, and equivalents which fall within the spirit and scope of the present invention.