Patent Publication Number: US-11039816-B2

Title: Needle biopsy device with exchangeable needle and integrated needle protection

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation of U.S. Ser. No. 13/297,766, filed Nov. 16, 2011, which is a continuation-in-part of U.S. Ser. No. 13/029,593 filed Feb. 17, 2011, which claims priority to U.S. Ser. No. 61/305,304, filed Feb. 17, 2010, and U.S. Ser. No. 61/305,396 filed Feb. 17, 2010. U.S. Ser. No. 13/297,766 is also; a continuation-in-part of U.S. Ser. No. 12/607,636, filed Oct. 28, 2009 (now U.S. Pat. No. 8,068,210), which claims priority to U.S. Ser. No. 61/117,966, filed Nov. 26, 2008, and U.S. Ser. No. 61/152,741, filed Feb. 16, 2009. U.S. Ser. No. 13/297,766 is also; a continuation-in-part of U.S. Ser. No. 12/243,367, filed Oct. 1, 2008 (now U.S. Pat. No. 9,186,128). The entire contents of each of the above-mentioned applications are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to the biopsy devices, and more particularly, needle biopsy devices for collecting tissue, fluid, and cell samples in conjunction with procedures such as endoscopic ultrasound or endoscopic bronchial ultrasound. 
     BACKGROUND INFORMATION 
     Endoscopic ultrasounds have been used for more than twenty five years within the field of medicine. These procedures allow clinicians to scan, locate and identify individual layers of the gastrointestinal (GI) tract and determine the location of individual mucosal and submucosal layers. As a result, appropriate therapeutic modes of treatment for malignancies and various abnormalities may be determined. 
     Endoscopic Ultrasound-Guided Fine-Needle Aspiration (“EUS—FNA”) and Endobronchial Ultrasound-Guided Fine-Needle Aspiration (“EBUS—FNA”) are currently standard modes of treatment in the field of GI Endoscopy and Bronchoscopy with high yields of sensitivity and specificity in the management of indications/diseases such as esophageal cancer, pancreatic cancer, liver mass, non-small cell lung cancer, pancreatic mass, endobronchial mass, and intra-abdominal lymph nodes. 
     A typical endoscopic ultrasound procedure consist of several steps. First, a clinician sedates a patient and inserts a probe via esophagogastroduodenoscopy into the patient&#39;s stomach and duodenum. Second, an endoscope is passed through the patient&#39;s mouth and advanced to the level of the duodenum. Third, from various positions between the esophagus and duodenum, organs or masses outside the gastrointestinal tract are imaged to determine abnormalities. If any abnormalities that are present, the organs and/or masses can be biopsied through the process of “fine needle aspiration” (FNA). 
     Endoscopic ultrasounds and endoscopic bronchial ultrasounds through fine needle aspiration are presently the standard modes of diagnosis and/or treatment in the field of gastrointestinal endoscopy and bronchoscopy. These procedures traditionally result in high yields of sensitivity and specificity in the management of indications of diseases such as esophageal cancer, pancreatic cancer, liver mass, non-small cell lung cancer, pancreatic mass, endobronchial mass, and intra-abdominal lymph nodes. 
     An endoscopic ultrasound through fine needle aspiration requires a device that is attached to the luer port or working channel of a typical echoendoscope. Prior art devices utilize a series of push and pull handles to control the axial movement of the catheter shaft of the device and the depth of needle penetration. These devices, however, suffer from several drawbacks. 
     One primary drawback of current FNA devices, concerns the lack of “Needle Safe Preventative” design features which protect the end user from inadvertent needle penetration and the transfer of blood-borne pathogens from patient subject to attending medical staff (Ref: The Needle-stick Safety and Prevention Act (HR 5178)—OSHA Regulation). 
     One of the primary issues still facing the medial device industry concerns the propensity for “Needle Stick”. The Occupational Health and Safety Administration (OSHA) has warned that most needle destruction devices (NDDs) are “not compliant” with the Bloodborne Pathogens Standard, which are defined as “ . . . controls (e.g., sharps disposal containers, self-sheathing needles, safer medical devices, such as sharps with engineered sharps injury protection and needleless systems) that isolate or remove the bloodborne pathogens hazard from the workplace.” To comply with the OSHA standard, an employer must use engineering and work practice controls that will “eliminate or minimize employee exposure” (OSHA Sec. 1910.1030(d)(2)(i)). OSHA&#39;s compliance directive explains that under this requirement “the employer must use engineering and work practice controls that eliminate occupational exposure or reduce it to the lowest feasible extent” (OSHA CPL 2-2.69 § XIII, D.2.). The employer&#39;s exposure control plan is to describe the method the employer will use to meet the regulatory requirement. The plan must be reviewed and updated at least annually to reflect changes in technology that will eliminate or reduce exposure (Sec. 1910.1030(c)(1)(iv)). 
     In the case of currently available FNA medical devices for both EUS and EBUS, once the sample has been aspirated from the desired anatomical location, the FNA catheter is removed from the echoendoscope and handed to the cytopathologist for sample extraction/preparation. The user is instructed to “re-sheath” the needle (i.e. retract the needle into the catheter sheath) prior to detachment from the echoendoscope. 
     However, in many instances, this does not occur. As such, the needle sharp of the device is exposed during removal and transfer of the FNA device among medical staff in the EUS/EBUS suite with increased risk of “needle sticking” and blood borne pathogen contamination/exposure to same. 
     Therefore, a need exists for an improved device for use in endoscopic ultrasound procedures which address the lack of adherence to OSHA HR 5178, of current EUS and EBUS Fine Needle Aspiration devices. 
     Additionally, prior FNA devices in the art are not designed to individually accommodate needles of various diameters. Prior art fine needle aspiration device design used in the field of endoscopic ultrasound sample acquisition, are designed such that the sampling needle is fully integrated into the handle drive mechanism of the device. Specifically, in the case of prior art devices, the full system needle biopsy device (handle and integrated needle) must be removed from an endoscope during a procedure if a clinician chooses to utilize needles of different sizes. In this instance, the sample aspirate is removed from the needle of the device with an en-suite cytopathologist. The removal and prepping of the aspirated sample is time consuming and results in significant wait-time for the clinician between needle biopsy system passes and sampling. 
     Another drawback of current FNA devices known in the art is that if the same needle biopsy system (as in the case of the prior art) is used throughout a procedure for sampling at numerous anatomical locations, the durability of both the needle and the stylette components of the device frequently become compromised (i.e. the needle and/or stylette components may take a “shape-set”, kink or fracture). This results in a prolonging of the procedure for the clinician, hospital staff and prolonged periods of sedation for the patient with a reduction in overall procedural efficiency. 
     In this instance, the clinician must remove the needle biopsy system from the endoscope; open a second new device of different needle size; re-insert the new device into the endoscope and re-confirm position of the endoscope and needle relative to the intended sampling site, before acquiring the sample. In many instances, the device may be un-useable after successive needle passes. In this instance, no alternative exists for the clinician but to utilize a new device for the remainder of the procedure. 
     A further drawback of prior art fine needle biopsy devices used in endoscopic and endobronchial ultrasound procedures concerns the lack of flexibility provided to the clinician during a procedure. 
     Current EUS-FNA needle biopsy systems are commercially available in needle sizes of 19, 22 and 25 gauge, with integrated handle and needle embodiments. In many instances the endoscopist or pulmonologist may desire to utilize a different size needle during a procedure. For example, a clinician may begin an endoscopic ultrasound or endobronchial ultrasound procedure with: (1) a device having a needle biopsy system with a diameter of 19 AWG; (2) aspirate the sample; (3) remove the needle biopsy system from the endoscope; (4) attach and lock a new needle biopsy device (for example, 22AWG size) to the endoscope and continue the procedure. This results in a loss of procedural efficiency for the clinician, patient and hospital and also increases procedural costs through the utilization of a second, new needle biopsy device. 
     Therefore, a need exists for an improved device for use in endoscopic ultrasound and endobronchial procedures which increases procedural efficiency, reduces procedural costs and improves procedural economics. 
     SUMMARY OF THE INVENTION 
     The invention provides a device for needle biopsy that includes a novel for a delivery handle system for interchangeably delivering needles of various sizes to a biopsy site. The delivery handle system has an adjustable length, a longitudinal axis defining a lumen extending therethrough, and includes a proximal handle member, a middle handle member and a distal handle member. The proximal handle member is slideably disposed over at least a portion of the middle handle member, the middle handle member is slideably disposed over at least a portion of the distal handle member. The proximal handle member includes an inner hub housing component having an internally cylindrical shape configured to interchangeably receive a needle subassembly that can be inserted into and withdrawn from the proximal handle member. 
     The needle subassembly for insertion into and withdrawal from the delivery handle system includes an aspiration needle of a plurality of different sizes, each needle having a proximal end portion and a distal end portion. Preferably, the aspiration needle ranges in size from a 15 AWG to a 28 AWG aspiration needle (e.g., 19 AWG, 22 AWG or 25AWG). A needle luer and a needle hub are coupled to the proximal end portion of the needle, the needle hub being configured for coupling with the inner hub housing component of the proximal handle member. The needle subassembly further includes a needle protector subassembly configured for coupling to the distal end portion of the needle. The needle protector subassembly includes a needle protection hub having a lumen extending therethrough configured for receiving the distal end portion of the needle, a deformable O-ring axially disposed within the lumen of the needle protection hub, and a tubular sheath defining a lumen extending from a distal end of the needle protection hub. The lumen of the tubular sheath is in communication with the lumen of the needle protection hub for receiving the needle when inserted into the needle protection hub. In one embodiment of the invention, the tubular sheath distally extending from the needle protector subassembly includes an internally tapering distal end. 
     In a preferred embodiment, the aspiration needle of the needle subassembly includes a collet surrounding the distal end portion of the needle. The collet has a diameter larger than the diameter of the deformable O-ring of the needle protection hub, such that the collet traverses the deformable O-ring when the needle is inserted into or withdrawn from the lumen of the needle protection hub, thereby locking the needle protector subassembly onto the distal end portion of the needle during insertion and withdrawal of the needle subassembly from the delivery handle system. The collet preferably chamfered at the proximal and distal ends to provide a smooth interface with the needle protector subassembly during needle exchange. 
     The aspiration needle of the needle subassembly also preferably includes a distal tip having four distinct angular bevel grinds, including a primary angle relative to the needle shaft, a secondary angle relative to the needle shaft, and a back-cut angle relative to the secondary angle for providing a smooth needle passage during needle insertion and withdrawal during a biopsy procedure. 
     The lumen extending through the delivery handle system includes an inner hypotube component at least partially disposed within the proximal handle member and an outer hypotube component disposed at least partially within the middle handle member. The inner hypotube is coupled to the outer hypotube and configured to longitudinally slide within the outer hypotube when the proximal handle member is distally advanced or proximally retracted over the middle handle member. The lumen further includes a tubular catheter sheath coupled to a distal end of the outer hypotube. The inner hypotube, outer hypotube and catheter sheath are in constant communication with each other. 
     Preferably, the catheter sheath includes a helically braided reinforcement structure and has an outer diameter ranging from 0.05 inches to 0.140 inches, and an inner diameter ranging from 0.05 inches to 0.120 inches. In certain embodiments, the catheter sheath includes a tapered distal tip having an outer and inner diameter that is smaller than the outer and inner diameters of the remaining length of the catheter sheath. In certain embodiments, the inner diameter of the distal tip ranges from 0.020 inches to 0.060 inches. 
     The delivery handle system of the invention further includes an inner handle member disposed within an inner portion of the middle handle member. The inner handle member is coupled to a proximal portion of the catheter sheath and a distal portion of the outer hypotube, such that the catheter sheath is distally extended into the distal handle member when the middle handle member is distally advanced over the distal handle member. 
     The delivery handle system of the invention further includes a first locking mechanism configured to prevent the proximal handle member from longitudinally sliding over the middle handle member, and a second locking mechanism configured to prevent the middle handle member from longitudinally sliding over the distal handle member. The first locking mechanism includes a first ring slideably disposed around at least a portion of the middle handle member. A screw is threaded within the first ring for locking the first ring in a fixed position along the middle handle member. The second locking mechanism includes a threaded insert disposed along a distal portion of the middle handle member. The threaded insert is coupled to a screw for tightening the threaded insert to lock middle handle member in a fixed position along the distal handle member. 
     The proximal handle member of the delivery handle system of the invention includes an inner retention collar disposed at a distal end of the inner hub housing component. The inner retention collar is configured to receive the needle protection hub coupled to the needle. At least a portion of the retention collar is recessed, and the deformable O-ring component is disposed within the recessed portion for securing the needle protection hub within the retention collar upon insertion of the needle subassembly into the proximal handle member. 
     In certain embodiments, the O-ring of the retention collar has a diameter smaller than a diameter of the needle protection hub, such that the needle protection hub traverses the deformable retention collar O-ring when the needle subassembly is inserted into or withdrawn from the proximal handle member thereby locking the needle protector subassembly onto the proximal handle portion during insertion and withdrawal of the needle subassembly from delivery handle system. 
     The proximal handle member further includes a locking mechanism for releasably locking the needle hub within the inner hub housing component of the proximal handle member. The locking mechanism includes a depressible latch component securely coupled to the proximal handle member. The latch includes a deflectable hinge coupled to a barb component, that is coupled to the inner hub housing component and disposed within an interior portion of the proximal handle member. 
     The needle hub of the needle subassembly includes an internal land ring for interacting with the deflectable hinge and barb component of the locking mechanism. The internal land ring traverses the deflectable hinge of the latch component when the needle subassembly is inserted into the lumen of the proximal handle member, thereby causing the deflectable hinge to deflect against the barb component during insertion. The deflectable hinge returns to a home position once the internal land ring has cleared the deflectable hinge to prevent the needle hub from moving backwards. The needle subassembly is released from the inner hub housing component of the proximal handle member by depressing the latching component to cause the deflectable hinge to deflect against the barb component to allow the internal land ring to clear the deflectable hinge and barb. 
     In certain embodiments, the inner hub housing component of the proximal handle member includes a plurality of depressions spaced around an internal circumference of the hub housing component and the needle hub comprises a plurality of protrusions. The plurality of depressions are configured to receive the plurality of protrusions to prevent the needle hub from rotating relative to the hub housing component. Alternatively, the inner hub housing component includes a smooth internal circumference and the needle hub comprises a smooth outer surface to allow the needle hub rotate relative to the hub housing component. 
     In certain embodiments, the delivery handle system of the invention includes a luer holder coupled to a distal end of the distal handle member for coupling the distal handle member to a working channel port of an endoscope. In such embodiments, the luer holder includes a luer lock for locking the distal handle member in a fixed position relative to the working channel of the endoscope to prevent the delivery handle system from rotating about the working channel. 
     These and other aspects of the invention are described in further detail in the figures, description, and claims that follow. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In the following description, various embodiments of the present invention are described with reference to the following drawings that illustrate exemplary embodiments of the invention. Together with the description, the drawings serve to explain the principles of the invention. In the drawings, like structures are referred to by like numerals throughout the several views. Note that the illustrations in the figures are representative only, and are not drawn to scale, the emphasis having instead been generally placed upon illustrating the principles of the invention and the disclosed embodiments. 
         FIG. 1  is an assembly drawing depicting the present invention incorporating the delivery system handle, catheter sheath and aspiration needle for the intended field of use. 
         FIG. 2  is a drawing of the aspiration needle sub-assembly of the present invention. 
         FIG. 3  is a cross sectional drawing of the needle protector embodiment of the present invention shown in  FIG. 2 . 
         FIG. 4  is a cross sectional drawing of the proximal end of the aspiration needle sub-assembly shown in  FIG. 2   
         FIG. 4A  is a drawing of an alternate preferred embodiment of the proximal end of the aspiration needle sub-assembly with strain relief; 
         FIG. 4B  is a cross sectional drawing of the proximal end of the aspiration needle sub-assembly with strain relief. 
         FIGS. 5A through 5D  depict various enlarged views of a thumb latch component included in the proximal portion of the delivery system handle of the invention. 
         FIG. 5  is a cross sectional drawing of the delivery system handle of the present invention. 
         FIG. 6  is an enlarged view of encircled Portion A shown in  FIG. 5 , and depicts a cross sectional drawing of the needle locking mechanism of the delivery system handle of the present invention. 
         FIG. 7  is an enlarged view of encircled Portion B shown in  FIG. 5 , and depicts cross sectional drawing of the needle extension length adjustment mechanism of the delivery system handle of the present invention. 
         FIG. 8  is an enlarged view of encircled Portion C shown in  FIG. 5 , and depicts a cross sectional drawing of the catheter sheath extension length adjustment mechanism of the delivery system handle of the present invention. 
         FIG. 9  is an enlarged view of encircled Portion D shown in  FIG. 5 , and depicts a cross sectional drawing of the distal end of the assembled delivery system handle of the present invention, incorporating the mechanism for attachment to the endoscope. 
         FIGS. 10A through 10O  depict exemplary embodiments of an echogenically enhanced region at the distal end of an aspiration needle for use in the devices of the invention. 
         FIG. 10  is a drawing of the distal end of the needle with mounted needle collet. 
         FIG. 11  is a drawing of the extreme distal end of the needle. 
         FIG. 12  is a drawing of the bevel detail of the needle of the present invention, incorporating primary angle, secondary angle, tertiary and back-cut angle elements. 
         FIG. 13  is a cross sectional drawing of the bevel detail of the needle of the present invention, illustrating the tertiary angle of the grind detail. 
         FIG. 14  is a cross sectional drawing of the proximal end of the needle protector hub sub-assembly. 
         FIG. 15  is a drawing of the intended functionality of the needle protector assembly. 
         FIG. 16  is a drawing of the intended functionality of the needle protector and aspiration needle assemblies during needle exchange and more specifically, during needle insertion. 
         FIG. 17  is a drawing of the intended functionality of the needle protector and aspiration needle assemblies during needle exchange and more specifically, during needle insertion and locking in the device handle. 
         FIG. 18  is a drawing of the locking functionality of the needle protector and aspiration needle sub-assemblies in the hub housing components of the device handle. 
         FIG. 19  is a cross-sectional drawing of locking functionality between the needle hub, thumb latch and hub housing components. 
         FIG. 20  is a drawing of the hub needle hub and hub housing with interlocking capability to ensure non-rotation. 
         FIG. 21  is an alternate embodiment of the present invention, to facilitate rotation between needle hub and hub housing components. 
         FIG. 22  is a drawing of the intended functionality of the present invention to withdraw the aspiration needle sub-assembly from the delivery system handle during needle exchange. 
         FIG. 23  is a drawing of the intended functionality of the needle collet during needle exchange and more specifically, during needle extraction from the device handle. 
         FIG. 24  is a drawing of the intended functionality of the needle collet during needle exchange and more specifically, during needle extraction from the device handle. 
         FIG. 25  is a drawing of the needle protector sub-assembly secured to the end of the aspiration needle, and the intended functionality of the needle sheath of the present invention. 
         FIG. 26  is a drawing of the distal end of the aspiration needle sub-assembly housed in the catheter sheath of the delivery system of the present invention. 
         FIG. 27  is a drawing of the distal end of the aspiration needle sub-assembly extending from the catheter sheath of the delivery system of the present invention. 
         FIG. 28  is a drawing of the intended functionality of the present invention, and more specifically of the intended functionality of the catheter sheath of the present invention. 
         FIG. 29  is a drawing of the construction of the catheter sheath component of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention provides a device for needle biopsy for collecting tissue, fluid, and cell samples in conjunction with procedures such as an endoscopic ultrasound (EUS) or endoscopic bronchial ultrasound (EBUS). 
     An exemplary embodiment of the proposed device assembly is illustrated in  FIG. 1 . The device design consists of a handle mechanism (delivery system handle  10 ) and aspiration needle sub-assembly  15 . The delivery system handle  10  includes a proximal handle member  10   a , a middle handle member  10   b , and a distal handle member  10   c . The proximal, middle and distal handle members each include an inner lumen and are coupled together to define a longitudinal axis such that the inner lumens are in constant communication and extends throughout the length of the coupled handle members. Proximal handle member  10   a  is slideably disposed over at least a portion of the middle handle member  10   b , and middle handle member  10   b  is slideably disposed over at least a portion of distal handle member  10   c . The proximal handle member  10   a  includes proximal handle grip  10   a   1  a distal handle grip  10   a   2 . The delivery handle system  10  further includes an inner handle member  10   d  disposed within the inner lumen of the middle handle member  10   b  (shown in  FIGS. 5 and 7 ). The delivery system handle  10  also incorporates a catheter sheath  14  component coupled to the distal end of the distal handle member  10   c . This component provides a conduit between the delivery system handle  10  and the target sampling site during the exchange of aspiration needles. The device design is modular in that the needle sub-assembly  15  can be detached from the proximal handle  10   a  of the device for each individual “pass” or aspirated sample taken by the endoscopist at the site of the lesion or abnormality. 
     The delivery system handle  10  incorporates two length adjustment features actuated via adjustment of two thumbscrew locking mechanisms. A threaded proximal thumbscrew  12  and locking ring  33  are moveably disposed around the middle handle member  10   b ; the proximal thumbscrew  12  is loosened to loosen locking ring  33 , locking ring  33  is moved distally along the middle handle member  10   b  and tightened in the desired position along middle handle member  10   b  via proximal thumbscrew  12  to allow the user to establish a set depth of needle penetration beyond the end of the catheter sheath  14 . A threaded distal thumbscrew  13  is transversely disposed at the distal portion of the middle handle member  10   b ; the distal thumbscrew  13  is loosened to move the middle handle member  10   b  distally and/or proximally and tightened to allow the user to establish a set depth of catheter sheath  14  extension beyond the end of the endoscope. 
     The needle sub-assembly  15  consists of the needle shaft  21 (which can range in length from 500 mm up to 2500 mm, but which more preferably ranges in length between 1640 mm to 1680 mm) and is beveled at the distal needle end to enhance tissue penetration during sample acquisition; needle hub  17 ; needle luer  18 ; needle collet  19 ; needle protector sub-assembly  9 ; stylette hub  20  and stylette shaft  22 . The needle component itself can be manufactured from a number of metallic based (Stainless steel or alloys thereof; Nitinol or Alloys thereof etc . . . ) or Polymeric Based materials including, but not limited to Poly-ether-ether ketone, Polyamide, Poyethersulfone, Polyurethane, Ether block amide copolymers, Polyacetal, Polytetrafluoroethylene and/or derivatives thereof). 
       FIG. 2  illustrates the aspiration needle sub-assembly  15  of the present invention. This sub-assembly is inserted into and removed from the lumen of the delivery system handle  10  in acquiring tissue samples. The sub-assembly  15  consists of a stylette hub  20  and stylette shaft  22  components which are securely locked on the needle luer  18  of the aspiration needle via conventional internal luer threads (as is know to persons skilled in the art). The stylette hub  20  may be attached to the stylette shaft  22  via a number of processing techniques such as adhesive bonding or insert injection molding. The female luer of the aspiration needle incorporates a mating luer thread detail, onto which the stylette hub  20  may be tightened. The needle luer  18  element of the present invention may be attached to the proximal end of the needle shaft via a number of processing techniques such as adhesive bonding or insert injection molding. 
     The aspiration needle sub-assembly  15  also incorporates a needle collet  19  (previously described as “needle protrusion(s) and shown in FIGS. 3 and 10 of Applicant&#39;s co-pending application (U.S. Ser. No. 12/243,367, published as US2010/0081965). The function of this needle collet  19  is to (1) provide a means to center the needle shaft component in the catheter sheath of the delivery system during needle exchange (2) provide a mechanism or securing and locking the needle protector sub-assembly to the distal end of the aspiration needle once the needle has been unlocked and withdrawn from the delivery system handle. The needle collet  19  of the present invention may be attached to the distal end of the needle shaft  21  via a number of processing techniques such as adhesive bonding, laser welding, resistance welding, or insert injection molding. The needle collet  19  may be fabricated from metals materials such as stainless steel, nickel titanium or alloys thereof or polymer materials such as, but not limited to, Polyacetal, polyamide, poly-ether-block-amide, polystyrene, Acrylonitrile butadiene styrene or derivatives thereof. The needle collet  19  is located at a set point distance from the extreme distal end of the beveled needle. The distance from the extreme distal end of the needle bevel to the proximal collet position on the needle may be within the range of 6 cm to 12 cm but is more preferably in the range of 7 cm to 9 cm and ore preferably is located 8 cm from the end of the needle. This ensures that when the needle is extended to it&#39;s maximum extension distance relative to the distal end of the catheter sheath (i.e. 8 cm), the collet  19  does not exit the end of catheter sheath  14 . 
       FIGS. 3 and 14  illustrate the needle protection sub-assembly  9  design embodiment of the current invention, in the locked position at the distal end of the needle. The needle protection sub-assembly  9  consists of two needle protector (NP) hub halves (collectively  23 ), which are adhesively bonded to each other, on the proximal end of the needle protector (NP) sheath component  24 . Alternately, these NP hub halves  23  may be snap fit together or may be insert injection molded over the NP sheath  24  to provide a secure bond/attachment between these components in the assembly. The needle protection sub-assembly  9  also incorporates a needle protector (NP) hub O-Ring component  25 . This component resides in a recessed cut-out in the center of the assembled NP hub halves  23 . This NP hub O-Ring  25 , in conjunction with the needle collet  19  which is securely attached to the distal end of the needle shaft  21  of the sub-assembly  9 , provides a mechanism for locking the NP sub-assembly  9  onto the end of the needle. In this way, the bevel of the needle is protected, covered and shielded once the needle has been removed from the delivery system handle. It is desired that the NP sheath  24  of the present invention be manufactured from a translucent polymer such as, but not limited to polyurethane, polyamide and derivatives thereof. 
     The needle hub  17  embodiment of the aspiration needle sub-assembly as shown in  FIG. 2  and  FIG. 4  of the present invention, provides a mechanism which (1) locks the aspiration needle sub-assembly  15  into the delivery system handle  10  by means of the hub housing  27  and thumb latch  28  components (as will be described later in this disclosure) and (2) provides a means to lock the needle protection sub-assembly  9  embodiment shown in  FIG. 3 , into the delivery system device handle  10 , as will be described later. As shown in  FIG. 4 , the needle hub component  17  is securely attached to the needle luer  18  and needle shaft  21  components of the aspiration needle sub-assembly  15 . The needle hub element  17  of the present invention may be attached to the distal end of the needle luer component  18  via a number of processing techniques such as adhesive bonding or insert injection molding. 
     An alternate preferred embodiment of the proximal end of the aspiration needle sub-assembly  15  is shown in  FIGS. 4A and 4B . This embodiment incorporates a strain relief component  26 , which extends from the distal end of the needle luer component  18 , through the body of the needle hub component  17 , to extend beyond the distal end of the needle hub  17 . This tubular strain relief component  26  is intended to provide a more gradual stiffness transition between the needle hub  17  and needle shaft  21  components, particularly in the case of smaller needle gauge sizes (such as 22A WG and 25A WG). This strain relief component  26  may range in length from 10 mm to 50 mm but is more preferably in the range of 25 mm to 35 mm. The diameter of this strain relief component  26  must be sufficiently small so that it fits through the proximal end of the needle protection sub-assembly  9  (as shown in  FIG. 3 ) and does not impair the ability for the NP sub-assembly  9  to slide back and forth on same. This strain relief component  26  may range in outer diameter from 0.020 inches to 0.060 inches but is more preferably in the range of 0.026 inches to 0.045 inches. This tubular strain relief  26  may be fabricated from metal based materials, such as but not limited to stainless steel, nickel titanium or alloys thereof or polymer materials such as, but not limited to, Polyacetal, polyamide, poly-ether-block-amide, polystyrene, Acrylonitrile butadiene styrene or derivatives thereof. 
       FIG. 5  is a sectional view of the delivery system handle  10  for the present invention, without the aspiration needle sub-assembly  15  loaded therein.  FIG. 6  (Detail A from  FIG. 5 ) illustrates a sectional view of the proximal end  10   a  of the assembled device handle. This proximal portion of the handle (also shown in  FIG. 16  and  FIG. 18 ) contains elements to ensure secure, yet releasable locking of the aspiration needle sub-assembly  15  in the delivery system handle  10 . The hub housing component  27  is secured to the proximal delivery system handle halves  10   a  via adhesive bonding or ultrasonic welding techniques. The thumb latch component  28  is securely locked into the hub housing component  27  via a one-way keying action. Once the thumb latch component  28  is inserted into the hub housing component  27 , the thumb latch  28  cannot be disassembled and may only be moved in the transverse direction to actuate the assembled mechanism. 
       FIGS. 5A, 5B, 5C, and 5D  depict various views of an exemplary embodiment of the thumb latch component  28  of the delivery system handle  10 . The thumb latch component  28  represents a mechanism to releasably lock the needle hub  17  of aspiration needle sub-assembly  15  within the hub housing  27  of the proximal handle member  10   a  of the delivery device. Thumb latch  28  may be, for example, a push-button, that activates the use of a deflectable hinge member  28   a  to provide for a return to the “home” position once external force is not applied to release thumb latch  28 . Hinge member  28   a  can elastically deform to provide for the opening and closing of the “lock” during removal of the aspiration needle sub-assembly  15  from the delivery system handle  10 . In one embodiment, thumb latch  28  incorporates an external coupler housing  28   b  and a push button design mechanism.  FIGS. 5C and 5D  illustrates thumb latch  28  in the CLOSED and OPEN positions during a typical actuation cycle. 
     Referring to  FIGS. 5A and 5B , thumb latch  28  and external coupler housing  28   b  may be manufactured from a range of rigid, non-deformable, thermoplastic or thermoset materials such as, acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), polystyrene or rigid derivatives thereof, polyamide, polyethylene, polyurethane, and polycarbonate. In an embodiment, the materials of manufacture have a durometer in the range of 35-120 Shore D, but more preferably in the range of 80-110 Shore D. 
     Hinge member  28   a  may be manufactured from a range of rigid, thermoplastic or thermoset materials such as, acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), polystyrene or rigid derivatives thereof, polyamide, polyethylene, polyurethane, and polycarbonate. In an embodiment, the materials of manufacture shall be capable of deformation in bending under the application of an applied load, such as is encountered during a typical “Open and Close” cycle for the needle biopsy device without crazing, fatigue or cracking. 
     The proximal portion of the proximal handle member  10   a  of the delivery system handle  10 , incorporates a retention collar  29  and a retention collar O-ring component  30 . The retention collar component  29  resides in a cut out nest in the proximal handle half, and is in communication with inner hub housing component  27 . The retention collar  29  is a cylindrical component, which is internally tapered and recessed to provide an internal, recessed shelf. The retention collar O-ring component  30  resides in this recessed shelf and is secured in position through the assembly of both halves of the delivery system handle halves. The purpose of this retention O-Ring component  30  is to provide a method to lock and maintain the needle protector hub sub-assembly  9  of the aspiration needle sub-assembly  15 , securely in the handle  10  of the delivery system while the tissue sample site is being accessed by the clinician, as described in detail below. The functionality and operation of this retention collar O-Ring component  30  is the same as described in FIGS. 41 and 42 and associated abstract of the specification of Applicant&#39;s co-pending patent application U.S. Ser. No. 12/607,636 (published as US2010/0121218). 
     As shown in  FIG. 6 , the delivery system handle assembly  10  of the present invention incorporates an inner hypotube component  31 . It is the design intent of this component to provide a conduit between the proximal handle member  10   a  of the delivery system, and the outer hypotube component  32  shown in  FIG. 7 . The inner hypotube component  31  may be fabricated from metal based materials, such as but not limited to stainless steel, nickel titanium or alloys thereof or polymer materials such as, but not limited to, Polyacetal, polyamide, poly-ether-block-amide, polystyrene, Acrylonitrile butadiene styrene or derivatives thereof. The inner hypotube  31  is secured to the assembled handle halves of the device via adhesive bonding or insert injection molding techniques. During needle advancement, the proximal handle member  10   a  of the delivery system is distally advanced, in order to advance the distal end of the needle into the desired tissue sampling site. When the proximal handle member  10   a  is distally advanced, the inner hypotube  31  is also advanced in unison in a distal direction. The inner hypotube component  31  is in constant longitudinal communication with the outer hypotube component  32  and is designed to telescope inside the outer hypotube component  32  at all times. This ensures that needle passage during needle exchange into and out of the delivery system, is not impaired. 
     Referring now to  FIG. 7  (Detail B from  FIG. 5 ), a cross sectional view of the distal end of the proximal handle member  10   a  and the middle handle member  10   b  is illustrated. During a typical EUS FNA procedure, the locking ring component  33  is loosened via proximal thumbscrew  12 , moved distally and set to a pre-established depth by the clinician, dependent upon depth of needle penetration required. Once the locking ring  33  has been moved distally (via the proximal thumbscrew) and locked to the required depth of penetration, the proximal handle member  10   a  of the delivery system is advanced. During advancement, the proximal handle member  10   a  moves in a longitudinal direction over the middle handle member  10   b  and inner handle member assembly  10   d . The inner handle member  10   d  and middle handle member  10   b  components are securely bonded to each via adhesive bonding or ultrasonic welding techniques and remain in a stationary, locked position during needle advancement via proximal handle  10   a  actuation in a distal direction. 
     As shown in  FIG. 7 , the outer hypotube component  32  is also in constant communication with the catheter shaft component  14  of the delivery system. The proximal end of the catheter shaft component  14  is flared in an outward direction. The distal end of the outer hypotube component  32  is inserted into flared end of the catheter shaft  14  and secured thereto via adhesive bonding or insert injection molding techniques. The inner handle member  10   d  is bonded to both the proximal end of the catheter shaft  14 /outer hypotube  32  assembly via adhesive bonding or insert injection molding techniques. In this way, the inner hypotube  31 , outer hypotube  32  and catheter sheath  14  are in constant communication, ensuring for smooth needle passage during needle exchange. This design embodiment, also ensures that the catheter sheath  14  my be advanced through the distal handle member  10   c  as required. 
       FIGS. 8 and 9  illustrate the design assembly embodiments for catheter sheath extension length adjustment in the case of the present invention. Referring to  FIG. 8 , the distal end of the middle handle member  10   b  incorporates a threaded insert  7  and distal thumbscrew  13 . The catheter sheath extension distance beyond the end of the endoscope may be adjusted by loosening the distal thumbscrew  13  and advancing the middle handle member  10   b  in a distal direction over the distal handle member  10   c . The distal handle member  10   c  and middle handle member  10   b  are in constant longitudinal communication with each other. 
     Referring to  FIG. 9 , the distal end of the delivery system handle assembly  10  is illustrated. The distal handle member  10   c  is secured to a recess in the distal luer holder  6  via adhesive bonding or ultrasonic welding techniques. The distal luer holder component  6  is securely attached to the scope luer lock component  5  via adhesive bonding or insert injection molding techniques. The distal handle member  10   c  is designed in such a way that once the device handle is attached to the working channel port of the endoscope, the assembly cannot rotate independently of assembled scope luer lock  5  and distal luer holder  6  components. Once the entire delivery system handle  10  (as shown in  FIG. 1  and cross sectional view  FIG. 5 ) has been locked onto the endoscope via the scope luer lock  5 , the catheter sheath length and needle penetration extension length may be established as previously described. 
       FIG. 10  is an illustration of the distal end of the aspiration needle of the present invention, with needle collet (referred to as “needle protrusions” in Applicant&#39;s co-pending patent application U.S. Ser. No. 12/607,636, published as US2010/0121218) secured on the needle. It is preferable that the length of this needle collet  19  be in the range of 2 mm to 10 mm, but more preferably in the range of 3.5 mm to 5 mm. It is preferable that the outer diameter of the needle collet  19  be in the range of 0.030 inches to 0.080 inches, but more preferably in the range of 0.040 inches to 0.070 inches. This needle collet component  19  (see also  FIG. 14  and  FIG. 26 ) is also chamfered at the proximal and distal ends of same. It is preferable that the chamfer angle of the needle collet be in the range of 15 degrees to 80 degrees, but more preferably in the range of 30 degrees to 60 degrees. This chamfer on both ends of the needle collet  19  is intended to provide smooth locking and unlocking with the needle protector sub-assembly  9  during needle exchanges. 
     As depicted in  FIG. 10 , and  FIGS. 10A through 10O , the distal end of the needle of the present invention incorporates an embodiment to enhance the echogenic signature of the needle. In the case of the present invention, this echogenically enhanced region  34  can be fabricated by, but not limited to roughening the end of the needle over a pre-defined length close to proximal end of the needle bevel  35 . It is preferable that the length of this echogenically enhanced region  34  be in the range of 2 mm to 20 mm, but is more preferably in the range of 10 mm to 15 mm. In the case of the present invention, the echogenic enhanced pattern is imparted to the needle via a micro-blasting process which roughens the surface of the needle over a specific length, improving the visibility of the needle under endoscopic ultrasound. 
     In certain aspects of the invention, the echogenically enhanced region of the needle is achieved through the removal of material from the surface of the needle to provide greater reflectivity and strengthened reflected signal. It is contemplated that the removal of material does not, however, reduce the performance of the needle from a pushability perspective or deter its ability to acquire a desired sample. 
     Referring now to  FIG. 10A , a perspective view of an embodiment of a needle  600  is presented. Needle  600  is comprised of a plurality of depressions  602 . Depressions  602  may be, but are not limited to, circular, concave, cylindrical, helical, oval, rectangular, and square elements that take the form of indentations on the surface of needle  600 . Depressions  602  may be arranged in a helical (spiral) fashion around the circumference of the distal needle end. These indentations may extend to the extreme end of the bevel or may end at a specific distance from the bevel of needle  600 . The length of the distal end of needle  600  containing these depressions may be, for example, from one to twenty centimeters. In another embodiment, the length is between five to ten centimeters. Referring to  FIGS. 10B and 10C , depression  602  have a concave detail  604 . Referring to  FIGS. 10D and 10E , depressions  602  have a square base edge  606 . Referring to  FIGS. 20F and 20G , depressions  602  have a hemispherical base detail  608 . 
     Referring now to  FIG. 10H , a perspective view of another embodiment of a needle  610  is presented. Needle  610  is comprised of elliptical depressions  612  around the circumference of the distal end of needle  610 . Referring to  FIG. 10I , a perspective view of an embodiment of a needle  614  having square depressions  616  is presented. Depressions  616  may extend to the extreme end of the bevel or may end at a specific distance from the bevel of needle  614 . Referring to  FIGS. 10J and 10K , embodiments of needle  614  including spiral depressions  620  and helical depressions  622  are presented. Referring to  FIG. 10L , a depression  624  has a concave detail. Referring to  FIG. 10M , a depression  626  has a square base edge. Referring to  FIG. 10N , a depression  628  has a hemispherical base detail. 
     Referring now to  FIG. 10O , a diagram of ultrasound waves impinging upon a needle depression at angles of α 1   630  and β 1   632  respectively are presented. In an embodiment, a wave strikes the base of the depression and is reflected upwards at angle of reflection of α 2   634  and β 2   636  respectively, which are equal to the angles of incidence of α 1   630  and β 1   632  respectively. This reflected beam is reflected a second time off the adjacent wall of the depression at an angle of reflection of α 3   638  and β 3   640  respectively, which are equal to the angles of incidence, α 1   630  and β 1   632  respectively and the angles of first reflection α 2   634  and β 2   636  respectively. In this manner, the reflected wave becomes reflected along the same angle of incidence as the initially propagated incident beam back to the transducer of the ultrasound device. In an embodiment, a square edge depression design may provide for more efficient remittance of ultrasound waves during the procedure. 
       FIGS. 11 and 12  are drawings of the distal end of the needle of the current invention. The distal end of the needle  35  of the current invention is beveled to enhance the ability of the needle to penetrate tissue during sample acquisition. The bevel detail  35  of the present invention incorporates four angular bevel grinds, which, in addition to enhancing tissue penetration, also ensure the smooth passage of the needle down the catheter sheath of the delivery system during needle exchange. Referring to  FIG. 12 , the needle bevel grind of the current embodiment incorporates a primary angle (“A”), a secondary angle (“B”), a back-cut angle (“C”) and tertiary angles (“D”), as shown in  FIG. 13 . It is preferable that the primary angle be in the range of 10 degrees to 25 degrees, but more preferably in the range of 12 degrees to 18 degrees. It is preferable that the secondary angle be in the range of 15 degrees to 35 degrees, but more preferably in the range of 22 degrees to 28 degrees. It is preferable that the tertiary angle be in the range of 15 degrees to 35 degrees, but more preferably in the range of 22 degrees to 28 degrees. It is preferable that the back-cut angle be in the range of 15 degrees to 70 degrees, but more preferably in the range of 25 degrees to 45 degrees. 
     During needle exchange, it is important that the aspiration needle (with pre-loaded stylette  2 ) can be passed through the internal diameter of the catheter sheath  14  without catching on the internal wall of same. In order to achieve this, the bevel grind of the current invention incorporates a back-cut grind detail. This back-cut detail acts as a “bumper” during needle passage through the sheath. As the needle advances, the heel of the back-cut comes in contact with the internal diameter of the sheath and reduces the friction between needle end  35  and catheter sheath  14  components. In this way, the needle can be smoothly tracked through the catheter sheath to exit the end of the catheter sheath  14 . 
       FIG. 14  and  FIG. 15  illustrate the method of engagement and disengagement between the aspiration needle sub-assembly  15  with mounted collet  19  and the needle protector (“NP”) sub-assembly  9 . Referring to  FIG. 14 , the NP hub  23  is locked onto the needle collet  19  at the distal end of the needle shaft  21  by inserting the shaft  21  into the NP hub  23 . As the needle/NP protector assembly is inserted into the handle of the delivery system, the needle  21  and needle collet  19  are advanced such that the needle collet  19  traverses the deformable NP Hub O-Ring  25 . The internal diameter of the NP Hub O-Ring  25  in the non-deformed state, is smaller than the outer diameter of the needle collet  19 . Due to the soft durometer and elastic nature of the NP Hub O-Ring  25 , as the needle  21  and attached needle collet  19  are moved distally, the NP O-Ring  25  deforms allowing the collet to traverse the NP O-ring  25  under applied longitudinal force. Once the needle collet  19  has traversed the NP O-ring  25 , the needle  21  with pre-mounted collet  19  are tracked through the catheter sheath  14  to the intended target site. This aspect of the current invention is also illustrated in  FIG. 23 . 
       FIGS. 16, 17 and 18  illustrate the mechanism by which the aspiration needle sub-assembly  15  is locked into the handle  10  of the delivery system. First, the aspiration needle sub-assembly  15  is pre-mounted with needle protection sub-assembly  9 , as previously described. As shown in  FIG. 16 , at the start of a needle insertion cycle, the aspiration needle/protection assembly is inserted into the proximal handle member  10   a  of the delivery system handle  10 . As the needle/protection assembly is advanced, the needle protector hub  23  contacts the retention collar o-ring  30 . Under application of additional force (as illustrated per  FIGS. 14 and 15 ) the needle collet  19  traverses the internal NP Hub O-ring  25  and advances distally down the catheter sheath  14 , as described above. As the needle hub  17  component is advanced into the hub housing component  27  of the proximal handle member  10   a , the distal end of the needle hub  17 , contacts the proximal end of the NP sub-assembly  9 . Continually inserting the needle hub  17 , pushes the NP sub-assembly  9  forward so that the NP hub  23  traverses the deformable retention collar o-ring  30  until it comes to rest. At this juncture, the NP hub  23  and sub-assembly  9  are locked in position within the proximal handle member  10   a  and do not move. Simultaneously, the needle hub  17  deflects the thumb latch component  28 . Once the NP sub-assembly  9  has traversed the retention collar o-ring  30  (as shown in  FIG. 18 ), the needle hub  17  is securely locked into the hub housing  27  by traversing an internal land ring  36  on the needle hub component  17 , as shown in Detail F of  FIG. 19 . 
       FIG. 19  illustrates a sectional view of the aspiration needle locked into the thumb latch  28 /hub housing  27  components of the delivery system handle  10 . As the needle hub  17  is advanced into the hub housing  27  in the handle, the hub  17  contacts the internal taper of the thumb latch  28  at the thumb latch distal end. This causes the thumb latch  28  distal end to move laterally and also causing the deflectable hinge  28   a  of the thumb latch  28  (see  FIG. 22  also) to deform under plastic deformation, against the hub housing barb  37 . Once the needle hub  17  is completely advanced into the hub housing  27 , the distal end portion of the thumb latch  28 , returns to the home position. The interference between the internal land ring  36  on the needle hub  17  and the thumb latch distal end, ensures that the needle hub  17  will not move backwards. 
     An intended functionality of thumb latch  28  is to prevent the aspiration needle subassembly  15  from being removed from the proximal handle member  10   a  without applying force to release thumb latch  28 . As shown in  FIG. 22 , the aspiration needle may be exchanged or withdrawn from the delivery system handle  10  by depressing the thumb latch component  28  and withdrawing the needle hub  17  from the hub housing  27 . As the thumb latch  28  is depressed, the deflectable hinge  28   a  of the thumb latch  28  contacts the hub housing barb  37 . The thumb latch  28  moves in a lateral direction. This action clears the interference between the internal needle hub land ring  36  and distal end of the thumb latch component  28 . In this way, the aspiration needle can be removed un-impaired from the delivery system handle. Additionally, follow-up samples may be acquired using the same or a virgin aspiration needle sub-assembly. 
       FIG. 20  illustrates the preferred embodiments of the hub housing  27  and needle hub  17  embodiments of the present invention. In this instance, the hub housing component  27  contains depressed female détentes  40  on the inner diameter of the hub housing  27 . These détente features  40  are equispaced around the internal circumference of the hub housing body. It is preferable that the number of détente features be in the range of 2 to 15, but more preferably in the range of 6 to 10. These détente features provide a mechanical lock with corresponding interlocking barb features  41  on the external surface of the needle hub barrel  17 . Once the needle hub  17  is securely locked in the hub housing component  27  in the device handle, the interlocking barbs  41  on the needle hub  17  become seated in the détente features  40  of the hub housing. This mechanical lock prevents the needle hub  17  from rotating relative to the needle hub housing  27  and delivery system handle  10 , during a typical endoscopic ultrasound procedure. Alternatively, the inner surface of the hub housing component  27  can be a smooth inner surface  27   a . Likewise, the external surface of the needle hub  17  is smooth external surface  17   a , to allow the needle hub  17  to rotate relative to the needle hub housing  27  and delivery handle system  10  during an endoscopic ultrasound procedures ( FIG. 21 ). 
     During aspiration needle exchange, and more specifically during needle insertion, the needle collet component  19  disengages from the NP Hub O-ring  25  by traversing the NP Hub O-ring  25  as explained above.  FIGS. 23 and 24  illustrate the engagement of the needle collet  19  with the needle protector sub-assembly  9  upon needle extraction post sample acquisition. As the aspiration needle is continually withdrawn from the delivery system handle  10 , the needle collet  19  contacts the NP hub O-ring  25  as shown in  FIG. 23 . As the aspiration needle is continually withdrawn, the needle collet  19  traverses the NP hub O-ring  25  as shown in  FIG. 24 . As the needle is further withdrawn, the needle protector hub  23  traverses the retention collar O-ring  30  and the needle can be completely removed from the system, with the needle protector sub-assembly  9  encasing the distal bevel of the needle  35  to prevent inadvertent “needle sticking”, as illustrated in  FIG. 25  and Detail G. 
     In the case of the present invention, the needle protector sheath  24  is internally tapered  24   a  at the distal end ( FIG. 25 ). It is preferable that length of this internal taper be in the range of 1 mm to 10 mm but more preferably in the range of 3 mm to 6 mm. It is also preferable that the internal taper angle on the distal end of the needle protector sheath be in the range of 2 degrees to 30 degrees, but more preferably in the range of 5 degrees to 15 degrees. 
       FIG. 26  is an illustration of the distal end  14   a  of the catheter sheath  14  of the delivery system (not shown) with aspiration needle loaded in the device handle, with the device handle in the fully retracted position. In this instance, the distal end of the needle lies proximal to the distal tapered end  14   a  of the catheter sheath  14 .  FIG. 27  illustrates the position of the needle  21  and needle collet  19  relative the catheter sheath  14  when the needle is in it&#39;s fully extended position. In the fully extended position, the needle collet  19  remains housed inside catheter sheath  14 , proximal to the tapered distal tip. 
     In the case of the present invention, the catheter shaft component  14  is manufactured from a thermoplastic polymer such as, but not limited to Polyurethane, Polyamide and derivatives thereof, Ether block amide copolymers, Polyimide, Placental, Polyethylene and derivatives thereof, Poly-tetrafluoroethylene. The preferred embodiment of the catheter shaft  14  (as shown in  FIG. 29 ) is that the catheter shaft  14  incorporates a helically braided reinforcing structure  45  housed between inner  46   a  and outer polymer  46   b  layers, of outer thermoplastic material such as those mentioned above with a lubricious inner liner or core. In the case of the present invention, the helically braided reinforcement  45  is fabricated from stainless steel wire. It is preferable that the diameter of this reinforcing braid wire be in the range of 0.0005 inches to 0.010 inches but more preferably in the range of 0.0015 inches to 0.005 inches It is preferable that the outer diameter of the catheter sheath  14  be in the range of 0.050 inches to 0.140 inches but more preferably in the range of 0.085 inches to 0.0105 inches. It is preferable that the inner diameter of the catheter sheath  14  be in the range of 0.050 inches to 0.120 inches but more preferably in the range of 0.065 inches to 0.085 inches. 
     In the case of the present invention (and as illustrated in  FIGS. 26 and 27 ), it is preferable that the distal end  14   a  of the catheter sheath  14  be tapered to reduce both the outer diameter and the internal diameter of the catheter sheath tip. This taper may be imparted to the distal end of the catheter sheath  14  via swaging or thermal heat forming techniques. It is preferable that the inner diameter of the catheter sheath  14  be tapered at the distal end  14   a  to an internal diameter in the range of 0.020 inches to 0.060 inches but more preferably in the range of 0.040 inches to 0.050 inches. 
     Referring now to  FIG. 28 , An aspect of the present invention which provides the clinician with improved procedural performance over prior art devices, concerns the ability of the tapered catheter sheath  14  of the present invention to keep the aspiration needle of the device centered in the working channel conduit of the endoscope. Due to the increased outer diameter of the catheter sheath  14  of the present invention (in the range of 6.5 French to 8 French) compared to that of the prior art (approximately 5 French to 5.4 French), the catheter sheath reduces the annular clearance between the catheter sheath  14  and the inner diameter of the endoscope working channel. By reducing the annular clearance with the working channel of the endoscope, the angle of exit of the catheter sheath  14  of the present invention is co-axial to working channel. This ensures that as the needle exits the distal end of the catheter sheath, the needle will exit the distal end of the catheter in a more “normal” plane relative to the longitudinal axis of the endoscope. The inclusion of an internal taper on the distal end of the catheter sheath, also ensures that the needle exits the catheter in a more “normal” plane than in the case of prior art devices. 
     Certain embodiments according to the invention have been disclosed. These embodiments are illustrative of, and not limiting on, the invention. Other embodiments, as well as various modifications and combinations of the disclosed embodiments, are possible and within the scope of the disclosure.