Patent Publication Number: US-10758213-B2

Title: Exchangeable core biopsy needle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of Ser. No. 14/595,392, filed Jan. 13, 2015, entitled, “EXCHANGEABLE CORE BIOPSY NEEDLE,” which is incorporated by reference in its entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure generally relates to biopsy devices, and, more particularly, to a biopsy needle configured for collecting tissue, fluid, and/or cell samples in conjunction with minimally-invasive procedures, such as endoscopic biopsy procedures. 
     BACKGROUND 
     In the practice of medical diagnostics, it is often necessary to perform a biopsy to remove a sample of a patient&#39;s tissue or fluid for pathological study. For example, biopsies can be useful in diagnosing various forms of cancer and other diseases affecting a localized area of tissue. Biopsy procedures may be used to take tissue and/or fluid samples from muscles, bones and organs, such as the liver or lungs. In some instances, a biopsy sample may be obtained by invasive surgical procedures. However, minimally invasive biopsy procedures are often preferred, such as fine needle aspiration and fine needle biopsy because such procedures are less traumatic to the patient. 
     Both fine needle aspiration (FNA) and fine needle biopsy (FNB) procedures generally include the use of a biopsy needle for collecting the target sample.  FIGS. 1 and 2  are provided to illustrate one embodiment of a biopsy needle  100  currently available for use in biopsy procedures. As shown, the needle  100  includes a shaft  102  portion extending from a proximal end (not shown) to a distal cutting end  104  of the needle  100 . The distal cutting end  104  includes a beveled leading end  106  resulting in a relatively sharp tip portion  110  used for puncturing the tissue to be sampled. The distal cutting end  104  of the needle  100  may be configured to cut and/or scrape target tissue to collect cells, tissue, or fragments. To sample the target area, the biopsy needle  100  may be guided to the tissue to be sampled through an instrument positioned in a patient. The instrument may be used with an endoscope, conduit and/or medical device insertion instrument. As shown, the needle  100  may be positioned within a sheath  108  of an endoscopic device, for example, such that the biopsy needle  100  may be retracted and extended from the sheath  108 . 
     Upon contacting the tissue to be sampled (via the distal cutting end  104 ), the tissue sample may be collected within a lumen  112  of the shaft  102 . In some devices, the needle  100  may extend from the sheath  108  and into the target tissue via a spring mechanism (not shown), such that the spring applies a force to the needle  100  and subsequently forces the distal cutting end  104  into the target tissue. Upon making contact with the target tissue, the distal cutting end  104  may separate a portion of the tissue from the surrounding tissue and collect the separated tissue within the lumen  112 , which may result in a “core” sample (e.g., a number of intact adjacent cells held together in similar form to their native location). Additionally, or alternatively, suction may be applied to the proximal end of the needle  100  so as to aspirate the sample (e.g., cells, tissue, etc.) through the distal cutting end  104  of the needle  100  and into the lumen  112 . 
     Generally, the goal of FNA and/or FNB is to acquire sufficient tissue to allow a diagnosis to be made. Currently, different needle tip configurations are used to collect different sample types (e.g., intact multi-cell samples useful for histology, cells and fragments useful for cytology, etc.). However, many existing biopsy needles are inefficient when collecting samples. For example, some needles use only about half or less of their inner diameter of the lumen to obtain tissue. Further, some current needle tip designs generally result in tearing of target tissue, which may result in a less than ideal core sample and unnecessary trauma to the surrounding tissue, which may cause further complications to the patient (e.g., internal bleeding, bruising, etc.) requiring further treatment. 
     Some devices that obtain a full cylinder or “full core” of tissue have difficulty in withdrawing tissue and/or in maintaining the physical state of the tissue so as to provide an accurate assessment of tissue condition. For example, some needles rely on scoring and/or mashing techniques during tissue collection, which may result in a damaged tissue sample. Depending on the diagnostics, physical characteristics of tissue, such as placement or orientation of cells or tissue, may be as important or more important than the chemical or biological characteristics (e.g. presence of malignant cells or by-products). 
     Furthermore, current needle tip designs may be insufficient for biopsy of certain types of tissue. For example, some lesions are particularly fibrous (e.g., pancreatic lesions) and are difficult to penetrate and obtain a suitable biopsy therefrom. Some bevel designs, such as the standard beveled cutting end of needle  100 , may initially pierce a portion of the target lesion, but may then deflect off of or drift from the target lesion due to the inadequate tip design and/or inability to fully penetrate the lesion, which results in a poor tissue sample, and may even lead to damage to surrounding tissues or vital organs. Additionally, current bevel designs may merely shear off a portion of the target tissue and fail to collect some, or even all, of the sampled tissue within the lumen of the needle due to inadequate tip design. 
     SUMMARY 
     The present disclosure provides a biopsy needle configured to maximize tissue sampling yield and further ensure collection of a cohesive unit of sampled tissue, thereby overcoming the drawbacks of current biopsy needles, which either provide an insufficient amount of a sample for analysis and/or damage a sample during the collection process. The biopsy needle of the present disclosure is able to overcome the drawbacks of current needles by providing a distinct distal cutting end configured to collect a full core of tissue sample and keep the full core intact. More specifically, the distal end includes at least a first tip portion and a second tip portion that radially oppose one another on either side of the needle body. The first tip portion is longer than the second tip portion, resulting in an increase in the surface area of one or more cutting edged extending between the first and second tip portions on either side of the needle body, particularly when compared to the cutting surface of a beveled leading distal end of a conventional biopsy needle (e.g., see the needle of  FIGS. 1 and 2 ). Additionally, because the first tip portion generally extends further than the second tip portion, the first tip portion is configured to initially pierce the tissue to be sampled with little or no resistance and further guide the sample tissue into the lumen of the biopsy needle. As the tissue is guided toward the lumen, second tip portion is further configured to capture and lead additional tissue towards the lumen to be excised by the cutting edge upon contact therewith. By increasing the effective cutting surface area and having the staggered configuration of first and second tip portions, the biopsy needle of the present disclosure is able to guide tissue into the lumen in a controlled manner and maximize the amount of tissue harvested, particularly upon aspiration. 
     In certain aspects, the present disclosure provides a biopsy needle that generally includes an elongate tubular body having a longitudinal axis and has a lumen extending therethrough from a proximal open end to a distal open end of the body. The distal end includes first and second tip portions extending therefrom. The first tip portion generally extends further from the distal end than the second tip portion, resembling a staggered configuration, where the first tip portion leads and the second tip portion follows. Accordingly, during a tissue collecting procedure, the first tip portion is configured to contact and engage the tissue to be sampled prior to the second tip portion. In some embodiments, the first and second tip portions are on opposing sides of the body. In some embodiments, the first and second tip portions are spaced apart in the range of 175 to 180 degrees along a circumference of the body. 
     The first tip portion is formed from a first set of distinct angular bevel grinds oblique to the longitudinal axis of the body and the second tip portion is formed from a second set of distinct angular bevel grinds oblique to the longitudinal axis of the body. The first set of angular bevel grinds includes first bevel grind on one side of the body and a second bevel grind on an opposing side of the body. The first and second bevel grinds converge with one another to define a first forward cutting edge of a penetrating tip of the first tip portion. In some embodiments, the first forward cutting edge is substantially perpendicular to the longitudinal axis of the body. 
     The first and second bevel grinds define first and second angles, respectively, relative to an outer surface of the body. In some embodiments, the first and second angles are in the range of 5 to 25 degrees. In some embodiments, the first and second angles are the same. The first set of angular bevel grinds further includes a back-cut bevel grind defining a substantially planar surface adjacent to the penetrating tip and defining a back-cut angle relative to an outer surface of the body and oblique to the outer surface of the body and the first and second bevel grinds. In some embodiments, the back-cut angle is 30 degrees. 
     The second set of angular bevel grinds includes a third bevel grind on one side of the body and a fourth bevel grind on an opposing side of the body. The third and fourth bevel grinds converge with one another to define a second forward cutting edge of a penetrating tip of the second tip portion. In some embodiments, the second forward cutting edge defines an oblique angle relative to the outer surface of the body, wherein the angle is in the range of 10 to 45 degrees. The third and fourth bevel grinds define third and fourth angles, respectively, relative to an outer surface of the body. In some embodiments, the third and fourth angles are in the range of 15 to 60 degrees. In some embodiments, the third and fourth angles are the same. 
     In some embodiments, the first set of bevel grinds includes a first bevel grind converging with a second bevel grind to form a penetrating tip of the first tip portion and the second set of bevel grinds includes a third bevel grind converging with a fourth bevel grind to form a penetrating tip of the second tip portion, wherein the first and third bevel grinds are one half of the body and intersect one another along a first intersection line and the second and fourth bevel grinds are on the other half of the body and intersect one another along a second intersection line. In some embodiments, the distal end includes at least four cutting edges formed between the first and second tip portions. A first cutting edge extends from the first intersection line to the penetrating tip of the first tip portion, a second cutting edge extends from the first intersection line to the penetrating tip of the second tip portion, a third cutting edge extends from the second intersection line to the penetrating tip of the first tip portion, and a fourth cutting edge extends from the second intersection line to the penetrating tip of the second tip portion. Each of the four cutting edges is configured to excise tissue upon contact therewith. 
     In some embodiments, the body may include a section having enhanced echogenicity or acoustic reflection. In some embodiments, the needle may further include a collet surrounding a portion of the body and having a diameter sufficient to prevent the body from entirely passing through a distal end of a sheath of a biopsy device. 
     In another aspect, the present disclosure includes a device for needle biopsy. The device includes an adjustable delivery handle system including a delivery handle, at least a portion of which includes an inner lumen configured to receive one of a plurality of exchangeable needle subassemblies. The adjustable delivery handle system further includes a sheath coupled to a distal end of the handle and having a lumen in fluid communication with the inner lumen of the delivery handle. The device further includes a needle subassembly removably disposed within the inner lumen of the delivery handle and lumen of the sheath, the needle subassembly including an exchangeable biopsy needle. The biopsy needle generally includes an elongate tubular body having a longitudinal axis and has lumen extending therethrough from a proximal open end to a distal open end of the body. The distal end includes first and second tip portions extending therefrom. The first tip portion generally extends further from the distal end than the second tip portion, resembling a staggered configuration, where the first tip portion leads and the second tip portion follows. Accordingly, during a tissue collecting procedure, the first tip portion is configured to contact and engage the tissue to be sampled prior to the second tip portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a biopsy needle known in the art. 
         FIG. 2  is a cross-sectional view of the biopsy needle of  FIG. 1 . 
         FIG. 3  is a perspective view of a portion of a biopsy needle consistent with the present disclosure. 
         FIG. 4  is a perspective view of a portion of a biopsy needle consistent with the present disclosure. 
         FIG. 5  is an enlarged side profile view of the distal end of the biopsy needle of  FIGS. 3 and 4 . 
         FIG. 6  is a bottom view of the distal end of the biopsy needle of  FIGS. 3 and 4 . 
         FIG. 7  is an enlarged side profile view of an alternative embodiment of a distal end of a biopsy needle consistent with the present disclosure. 
         FIG. 8  is an enlarged side profile view, partly in section, of a distal end of another embodiment of a biopsy needle consistent with the present disclosure. 
         FIG. 9  is an enlarged side profile view of the distal end of the biopsy needle of  FIG. 8  in greater detail. 
         FIG. 10  is a bottom view of the distal end of the biopsy needle of  FIG. 8 . 
         FIG. 11  is a top view of the distal end of the biopsy needle of  FIG. 8 . 
         FIG. 12  is a front view of the distal end of the biopsy needle of  FIG. 8 . 
         FIG. 13  is a perspective view of a biopsy device including an adjustable delivery handle and sheath for receipt of and use with an exchangeable biopsy needle consistent with the present disclosure. 
         FIG. 14  is a drawing of the needle sub-assembly of the device of  FIG. 13 . 
         FIG. 15  is a cross sectional drawing of the needle protector embodiment of the needle sub-assembly of  FIG. 14 . 
         FIG. 16  is a cross sectional drawing of the needle hub at the proximal end of the biopsy needle sub-assembly of  FIG. 14 . 
         FIG. 17  is a perspective view of a biopsy needle consistent with the present disclosure. 
         FIG. 18A  is a side view, partly in section, of storage of the biopsy needle of  FIG. 17  within the sheath of  FIG. 13 . 
         FIG. 18B  is a side view, partly in section, of extension of the biopsy needle of  FIG. 17  from the sheath of  FIG. 13 . 
         FIG. 19A  is a side view, partly in section, of storage of the biopsy needle of  FIG. 8  within the sheath of  FIG. 13  showing the stylet shaft within the biopsy needle. 
         FIG. 19B  is a side view, partly in section, of extension of the biopsy needle and stylet shaft from the sheath. 
         FIG. 19C  is a side view, partly in section, of withdrawal of the stylet shaft from within at least the distal end of the biopsy needle to expose the first and second tip portions for sample tissue collection. 
         FIG. 20  is a perspective view illustrating the initiation of sample tissue collection with a biopsy needle consistent with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     By way of overview, the present disclosure is generally directed to a biopsy needle configured for collecting tissue, fluid, and/or cell samples in conjunction with minimally-invasive procedures, such as endoscopic biopsy procedures. As described in greater detail herein, a biopsy needle consistent with the present disclosure may be used in Endoscopic Ultrasound (EUS) and Endobronchial Ultrasound (EBUS) procedures, particularly EUS Fine Needle Aspiration (FNA), EUS Fine Needle Biopsy (FNB), EUS Coring, and EBUS procedures for the purpose of harvesting tissue specimen from a targeted site. It should be noted, however, that the biopsy needle may be used in other minimally-invasive procedures, and is not limited to EUS and/or EBUS procedures. 
     In one aspect, a biopsy needle consistent with the present disclosure includes an elongate tubular body having a longitudinal axis and a lumen extending therethrough from a proximal open end to a distal open end of the body. The distal end includes at least a first tip portion and a second tip portion that radially oppose one another on either side of the needle body. The first tip portion is longer than the second tip portion, resulting in an increase in the surface area of a cutting edge extending between the first and second tip portions, particularly when compared to the cutting surface of a beveled leading distal end of a conventional biopsy needle (e.g., see the needle of  FIGS. 1 and 2 ). 
     Because the first tip portion is longer than the second tip portion, the first tip portion is configured to initially pierce the tissue to be sampled with little or no resistance and further guide the sample tissue into the lumen of the biopsy needle. As the tissue is guided toward the lumen, the second tip portion captures and leads additional tissue towards the lumen. During this process the tissue is excised by the cutting edge, creating a contiguous core biopsy sample. By increasing the effective cutting surface area and having the staggered configuration of first and second tip portions, the biopsy needle of the present disclosure is able to guide tissue into the lumen in a controlled manner and maximize the amount of tissue harvested, particularly upon aspiration. 
     The distinct distal cutting end of a biopsy needle consistent with the present disclosure is configured to collect a full core of tissue sample while keeping the full core intact. Accordingly, a biopsy needle consistent with the present disclosure is configured to maximize tissue sampling yield and further ensure collection of a cohesive unit of sampled tissue so as to provide a more complete sample for testing, which may improve the accuracy and/or timing of diagnosis. 
       FIGS. 3 and 4  show a distal portion a biopsy needle  200  consistent with the present disclosure. As shown, the needle  200  generally includes an elongate tubular body  202  having a lumen  203  extending through the body  202  from a proximal open end (not shown) to a distal open end  204 . The distal end  204  is configured for collection and harvesting of a sample, including, but not limited to, tissue, fluid, and/or cell samples. In particular, the distal end  204  is beveled in a distinct configuration so as to enhance the ability of the needle  200  to penetrate and collect tissue during sample acquisition. 
     The distal end  204  includes a first tip portion  206  and a second tip portion  210  extending therefrom, wherein the first and second tip portions  206 ,  210  are formed on opposing sides of the needle body  202 , such that the tip portions radially oppose one another. The first and second tip portions  206 ,  210  each include a point  208 ,  212 , respectively. The points  208 ,  212  are configured to penetrate a tissue sample, with relatively little or no resistance during tissue sampling procedure and further configured to direct tissue towards the lumen  203  of the body  202 . 
     The first tip portion  206  is generally formed from at least a first bevel grind  214  (shown on one side of the needle body  202 ) and the second tip portion  210  is formed from at least a second bevel grind  216 , wherein the first and second bevel grinds  214 ,  216  are different from one another. The differing bevel grinds  214 ,  216  result in different lengths of the first and second tip portions  206 ,  210 . For example, the first tip portion  206  has a length L 1  and the second tip portion  210  has a length L 2 . The lengths L 1  and L 2  are each measured from an apex of an arcuate cutting edge shared between the first and second tip portions  206 ,  210  (shown in  FIG. 6 ) and the corresponding points  208 ,  212 . In the illustrated embodiment, L 1  is greater than L 2 , such that the first tip portion  206  is essentially longer and extends further from apex than the second tip portion  210 , such that the first and second tip portions  206 ,  210  are in a staggered configuration. As such, the first tip portion  206  is configured to contact and engage tissue to be sampled prior to contact and engagement of tissue by the second tip portion  210 , which provides associated benefits, as will be described in greater detail herein. In some embodiments, at least one of the first and second tip portions  206 ,  210  includes a back-cut grind  218 ,  220  adjacent the respective point  208 ,  212 . Among other benefits, the back-cut grind  218 ,  220  is configured to provide a smooth needle passage during needle insertion and withdrawal during a biopsy procedure, described in greater detail herein. 
     The distal end  204  further includes at least one curvilinear, or arcuate, cutting edge  222  extending between the first tip portion  206  and the second tip portion  210 . The cutting edge  222  is generally formed by the first and second bevel grinds  214 ,  216  of the first and second tip portions  206 ,  210 . During a tissue collection procedure, the cutting edge  222  is configured to excise tissue upon contact therewith and further allow the excised tissue sample to translate into the lumen  203  and contact the internal surface  224  of the lumen  203  for harvesting. 
       FIG. 5  is an enlarged side profile view of the distal end  204  of the biopsy needle  200 . As shown, the cutting edge  222  generally extends entirely from the point  208  of the first tip portion  206  to the point  212  of the second tip portion  210 . However, it should be noted that in other embodiments, the cutting edge  222  may only partially extend between distinct portions of the first and second tip portions  206 ,  210 . In one embodiment, at least one of the first and second tip portions  206 ,  210  includes a back-cut grind. In another embodiment, i.e., as shown in the figures, both the first and second tip portions  206 ,  210  include a back-cut grind  218 ,  220 , respectively. Each back-cut grind  218 ,  220  includes a back-cut angle oblique to an outer surface of the needle body  202 . For example, back-cut grind  218  has a back-cut angle A and back-cut grind  220  has a back-cut angle B, wherein angles A and B are in the range of 15 degrees to 70 degrees, but more preferably in the range of 25 degrees to 45 degrees. In one embodiment, the back cut angles A and B are 30 degrees. 
     The inclusion of at least back-cut grind  218  on the first tip portion  206  may ensure the smooth passage of the needle down a sheath, or other enclosure of a delivery device, during needle movement and/or exchange. For example, the biopsy needle  200  of the present disclosure may be used in conjunction with a delivery device, such as an endoscopic device for delivering the needle  200  to the target site for tissue collection. The endoscopic device may generally include a sheath, or other enclosure, for provide the needle  200  with access to a target site for tissue collection. As such, during a needle exchange, for example, it is important that the needle  200  can be passed through an internal diameter of a sheath of the delivery device without catching on an internal wall of the sheath. As the needle advances, the heel of the back-cut grind  218  may come in contact with the internal diameter of the sheath and reduce the friction between the distal end  204  of the needle  200 , particularly the point  208  of the first tip portion  206 , and the sheath. In this way, the needle  200  can be smoothly tracked through the sheath to exit the end of the sheath. This feature also makes it easy to remove a needle and re-insert a new needle while the rest of a delivery device remains within a patient during a procedure. 
       FIG. 6  is a bottom view of the distal end  204  of the biopsy needle  200  illustrating sets of bevel grinds that form the distal end  204 . As shown, the first and second tip portions  206 ,  210  are formed from first and second sets of distinct angular bevel grinds that enhance tissue penetration and collection. For example, the first tip portion  206  is formed from a first set of distinct angular bevel grinds oblique to the longitudinal axis X of the needle body  202 . The first set of angular bevel grinds comprises at least a first angle Con one side of the body  202  and a second angle C′ on the opposing side of the body  202 , wherein both angles C and C′ are oblique to the longitudinal axis X of the body  202 . In one embodiment, angles C and C′ may be the same. In other embodiments, angles C and C′ may be different. The first and second angles C and C′ are in the range of 5 to 40 degrees. In some embodiments, the first and second angles C and C′ are in the range of 5 to 20 degrees. In one embodiment, the first and second angles C and C′ are 15 degrees. 
     Similarly, the second tip portion  210  is formed from a second set of distinct angular bevel grinds oblique to the longitudinal axis X of the needle body  202 . The second set of angular bevel grinds comprises at least a third angle D on one side of the body  202  and a fourth angle D′ on the opposing side of the body  202 , wherein both angles D and D′ are oblique to the longitudinal axis X of the body  202 . In one embodiment, angles D and D′ may be the same. In other embodiments, angles D and D′ may be different. The third and fourth angles D and D′ are in the range of 15 to 40 degrees. In some embodiments, the third and fourth angles D and D′ are in the range of 20 to 30 degrees. In one embodiment, the third and fourth angles D and D′ are 25 degrees. The first and second sets of angular bevel grinds described herein can be formed on the needle by any known processes, including, but not limited to, CNC needle grinding, laser cutting, and other needle tip forming techniques. Further, upon formation of the bevels, the distal end  204  undergoes treatment to remove all burrs and unwanted sharp edges as a result of the beveling process. 
     In the illustrated embodiment, the first and second sets of angular bevel grinds are different than one another. For example, in one embodiment, the first and second angles C and C′ (forming the first tip portion  206 ) are approximately 15 degrees and the third and fourth angles D and D′ (forming the second tip portion  210 ) are approximately 25 degrees. Accordingly, the first and second angles C and C′ are less than the third and fourth angles D and D′, resulting in the first and second tip portions  206 ,  210  having different associated lengths. For example, the first tip portion  206  has a length L 1  (measured from the point  208  to an apex of the arcuate cutting edge  222 ) and the second tip portion  210  has a length L 2  (measured from the point  212  to an apex of the arcuate cutting edge  222 ), wherein L 1  is greater than L 2 . Accordingly, the first tip portion  206  is longer and extends further from the distal end  204  than the second tip portion  210 , such that the first and second tip portions  206 ,  210  are in a staggered configuration and the first tip portion  206  leads during tissue collection. More specifically, the first tip portion  206  is configured to contact and engage tissue to be sampled prior to contact and engagement of tissue by the second tip portion  210 . The lengths L 1  and L 2  of the first and second tip portions  206 ,  210  are in the range of 0.5 to 5 mm. In some embodiments, the length L 1  is in the range of 2 to 3 mm and the length L 2  is in the range of 0.5 to 1.5 mm. In one embodiment, the first tip portion  206  has a length L 1  of approximately 2.0618 mm and the second tip portion  210  has a length L 2  of approximately 1.3 mm. It should be noted that the first and second sets of angular bevel grinds may be manipulated so as to result in adjustment of lengths L 1  and L 2  of the first and second tip portions, respectively. 
     The distinct configuration of the distal end  204  of the biopsy needle  200  is configured to maximize tissue sampling yield and further ensure collection of a cohesive unit of sampled tissue, thereby overcoming the drawbacks of current biopsy needles (such as needle  100  of  FIGS. 1 and 2 ). For example, by providing a staggered configuration of the first and second tip portions  206 ,  210 , the surface area of the effective cutting edge  222  is increased when compared to beveled leading distal ends of current biopsy needles (e.g., Menghini, Franseen, Quicke, etc.). Additionally, because the first tip portion  206  is longer than the second tip portion  210 , the first tip portion  206  is configured to initially pierce the tissue to be sampled with little or no resistance and further guide the sample tissue into the lumen  203  of the biopsy needle  200 . If the first and second tip portions  206 ,  210  were of equal length, it may prove more difficult to initially puncture of tissue sample, particularly a fibrous tissue. Furthermore, as the tissue is guided toward the lumen  203 , the second tip portion  210  is further configured to capture and lead additional tissue towards the lumen  203  to be excised by the cutting edge  222  upon contact therewith. By increasing the effective cutting surface area and having the staggered configuration of first and second tip portions  206 ,  210 , the biopsy needle  200  of the present disclosure is able to guide tissue into the lumen in a controlled manner and maximize the amount of tissue harvested, particularly upon aspiration. 
     It should be noted that a biopsy needle consistent with the present disclosure is not limited to the number of tip portions (e.g., two tip portions). For example,  FIG. 7  is an enlarged side profile view of an alternative embodiment of a distal end  304  of a biopsy needle  300  having at least four tip portions extending from the distal end. As shown, the needle  300  may include first and second tip portions  306 ,  314  (similar to needle  200 ), and an additional third tip portion  310  and fourth (generally opposite the third  310 ) tip portion formed between the first and second tip portions  306 ,  314 , wherein the first and second tip portions  306 ,  314  radially oppose one another on either side of the needle body  302  and the third and fourth tip portions radially oppose one another on either side of the needle body  302 . As shown, the first tip portion  306  is longer than the third (and fourth) tip portion  310 , which is longer than the second tip portion  314 , such that distal end  304  maintains a staggered configuration. The inclusion of additional tip portions may further increase the surface area of cutting edges  320 ,  324  formed between the tip portions, which may be particularly beneficial when sampling certain types of tissue that may prove to be tough or resistant to cutting (e.g., fibrous tissue). 
       FIGS. 8-12  illustrate another embodiment of a biopsy needle  400  having a distal end  404  beveled in a distinct configuration so as to enhance the ability of the needle  400  to penetrate and collect tissue during sample acquisition. As shown, and described in greater detail herein, the distal end  404  includes at least five angular bevel grinds resulting in the formation of two opposing tip portions arranged in a staggered configuration, such that one of the tip portions is longer than the other, and multiple cutting edges are further defined between the opposing tip portions. As described in greater detail herein, this distinct distal cutting end is designed to overcome the drawbacks of current biopsy needles, which either provide an insufficient amount of a sample for analysis and/or damage a sample during the collection process. 
       FIG. 8  is an enlarged side profile view, partly in section, of the distal end  404  of the biopsy needle  400 .  FIG. 9  is an enlarged side profile view of the distal end  404  in greater detail and  FIG. 10  is a bottom view of the distal end  404 .  FIGS. 11 and 12  are top and front views, respectively, of the distal end  404  of the biopsy needle  400 . As shown, the needle  400  generally includes an elongate tubular body  402  having a lumen  403  extending through the needle body  402  from a proximal open end (not shown) to a distal open end  404 . The distal end  404  is configured for collection and harvesting of a sample, including, but not limited to, tissue, fluid, and/or cell samples. In the illustrated embodiment, the distal end  404  includes a first tip portion  406  and a second tip portion  410  formed on opposing sides of the needle body  402 , such that the tip portions  406 ,  410  generally oppose one another. The first and second tip portions  406 ,  410  each include a penetrating tip  408 ,  412 , respectively, configured to penetrate a tissue sample, with relatively little or no resistance during tissue sampling procedure and further configured to direct tissue towards the lumen  403  of the body  402 . 
     The first and second tip portions  406 ,  410  are formed from first and second sets of distinct angular bevel grinds configured to enhance tissue penetration and collection. For example, the first tip portion  406  is formed from a first set of distinct angular bevel grinds oblique to the longitudinal axis X of the needle body  402 . As shown, the first tip portion  406  is formed from a first bevel grind  414   a  on one side of the needle body  402  and a second bevel grind  414   b  on an opposing side of the body, wherein the first and second bevel grinds  414   a ,  414   b  converge with one another to define a forward cutting edge  409  of the penetrating tip  408 . In some embodiments, the forward cutting edge  409  may substantially perpendicular to the longitudinal axis X of the needle body  402 . In other embodiments, the forward cutting edge  409  may be oblique to the longitudinal axis X. 
     As shown, the first and second bevel grinds  414   a ,  414   b  may be substantially similar and thus each defines a similar angle relative to the needle body  402 . Accordingly, for ease of description, only one angle, as defined by the first bevel grind  414   a , is shown and described. For example, the first bevel grind  414   a  defines an angle G relative to an outer surface of the needle body  402 , wherein angle G is acute and in the range of 5 to 40 degrees. In some embodiments, angle G is in the range of 10 to 20 degrees. In one embodiment, angle G is 12 degrees. It should be noted that in some embodiments, the first and second bevel grinds  414   a ,  414   b  may be different (e.g., have different lengths, define different angles, etc.). 
     The first tip portion  406  may further include a back-cut bevel grind  420  forming a substantially planar surface adjacent to the penetrating tip  408 . The back-cut bevel grind  420  generally defines a back-cut angle oblique to an outer surface of the needle body  202  and the first and second bevel grinds  414   a ,  414   b . For example, back-cut bevel grind  420  generally defines a back-cut angle E in the range of 15 degrees to 70 degrees, but more preferably in the range of 25 degrees to 45 degrees. In one embodiment, the back cut angle E is 30 degrees. Similar to the back-cut bevel grinds of needle  200 , the inclusion of the back-cut bevel grind  420  on the first tip portion  406  may ensure the smooth passage of the needle  400  down a sheath, or other enclosure of a delivery device, during needle movement and/or exchange. For example, the biopsy needle  400  of the present disclosure may be used in conjunction with a delivery device, such as an endoscopic device for delivering the needle  400  to the target site for tissue collection. The endoscopic device may generally include a sheath, or other enclosure, for provide the needle  400  with access to a target site for tissue collection. As such, during a needle exchange, for example, it is important that the needle  400  can be passed through an internal diameter of a sheath of the delivery device without catching on an internal wall of the sheath. As the needle advances, the heel of the back-cut bevel grind  420  may come in contact with the internal diameter of the sheath and reduce the friction between the distal end  404  of the needle  400 , particularly the penetrating tip  408  of the first tip portion  406 , and the sheath. In this way, the needle  400  can be smoothly tracked through the sheath to exit the end of the sheath. This feature also makes it easy to remove a needle and re-insert a new needle while the rest of a delivery device remains within a patient during a procedure. 
     The second tip portion  410  is formed from a second set of distinct angular bevel grinds oblique to the longitudinal axis X of the needle body  402 . As shown, the second tip portion  410  is formed from a third bevel grind  416   a  on one side of the needle body  402  and a fourth bevel grind  416   b  on an opposing side of the body, wherein the third and fourth bevel grinds  416   a ,  416   b  converge with one another to define a forward cutting edge  413  of the penetrating tip  412 . In some embodiments, the forward cutting edge  413  may substantially perpendicular to the longitudinal axis X of the needle body  402 . In other embodiments, the forward cutting edge  413  may be oblique to the longitudinal axis X. For example, in the illustrated embodiment, the forward cutting edge  413  defines an oblique angle F relative to the outer surface of the needle body  402 , wherein angle F is acute and in the range of 5 to 80 degrees. In some embodiments, angle F is in the range of 10 to 60 degrees. In one embodiment, angle F is 20 degrees. 
     As shown in  FIG. 9 , the first bevel grind  414   a  and third bevel grind  416   a  are formed on one half of the needle body  402 , such that the first and third bevel grinds  414   a ,  416   a  intersect one another along a first intersection line  418   a . In some embodiments, the first intersection line  418   a  defines an oblique angle relative to the longitudinal axis X of the needle body  402 . Similarly, the second bevel grind  414   b  and fourth bevel grind  416   b  are formed on the other half of the needle body  402 , such that the second and fourth bevel grinds  414   b ,  416   b  intersect one another along a second intersection line  418   b  opposite the first intersection line  418   a . In some embodiments, the second intersection line  418   b  defines an oblique angle relative to the longitudinal axis X of the needle body  402 . As shown, the third and fourth bevel grinds  416   a ,  416   b  may be substantially similar and thus each defines a similar angle relative to the outer surface of the needle body  402 . In some embodiments, each of the third or fourth bevel grinds  416   a ,  416   b  may define an acute angle in the range of 15 to 60 degrees. 
     The distal end  404  of the needle  400  further includes multiple cutting edges as formed by the multiple bevel grinds. As shown in  FIGS. 8-12 , a first cutting edge  422  is defined along one side of the first tip portion  406 , extending from the penetrating tip  408  to the first intersection line  418   a  in a generally arcuate configuration. The first cutting edge  422  is generally formed by the first bevel grind  414   a . A second cutting edge  424  is defined along one side of the second tip portion  410 , extending from the penetrating tip  412  to the first intersection line  418   a  in a generally arcuate configuration. The second cutting edge  424  is generally formed by the second bevel grind  414   a . As shown in  FIG. 12 , a third cutting edge  426  is defined along the other side of the first tip portion  406 , extending from the penetrating tip  408  to the second intersection line  418   b  in a generally arcuate configuration and a fourth cutting edge  428  is defined along the other side of the second tip portion  410 , extending from the penetrating tip  412  to the second intersection line  418   b  in a generally arcuate configuration. During a tissue collection procedure, each of the cutting edges (e.g., forward cutting edges  409  and  413 , and first, second, third, and fourth cutting edges  422 - 428 ) is configured to excise tissue upon contact therewith and further allow the excised tissue sample to translate into the lumen  403  and contact the internal surface  430  of the lumen  403  for harvesting. 
     As shown in  FIGS. 8-10 , the first and second tip portions  406 ,  410  are of different lengths, wherein the first tip portion  406  extends further from the needle body  402  than the second tip portion  410 , such that the first and second tip portions  406 ,  410  are in a staggered configuration. As such, during movement of the needle body  402  in a direction towards a surface of the tissue to be sampled, the first tip portion  406  is configured to contact and engage the tissue prior to contact and engagement of tissue by the second tip portion  410 , which provides associated benefits, as will be described in greater detail herein. 
     As shown in  FIG. 10 , for example, the penetrating tip  408  of the first tip portion  406  extends further from the needle body  402  than the penetrating tip  412  of the second tip portion  410 , such there is a difference in length L 3  between the penetrating tips  408 ,  412 . For example, in one embodiment, the difference in length L 3  is at least 0.021 mm. In another embodiment, the difference in length L 3  is at least 0.028 mm. In another embodiment, the difference in length L 3  is at least 0.051 mm. 
     The first and second tip portions  406 ,  410  are generally formed on opposing sides of the needle body  402 , as shown in  FIGS. 8-12 . For example, as shown in  FIG. 12 , when viewing the needle  400  from a front distal end view, the penetrating tips  408 ,  412  of the first and second tip portions  406 ,  410 , respectively, radially oppose one another. An angle H may be defined between the forward cutting edges  409 ,  413  of the penetrating tips  408 ,  412  when viewed along the longitudinal axis X (view depicted in  FIG. 12 ). In some embodiments, angle H may be in the range of 100 to 180 degrees. In some embodiments, angle H may be in the range of 125 to 180 degrees. In some embodiments, angle H may be in the range of 150 to 180 degrees. In some embodiments, angle H may be in the range of 175 to 180 degrees. In one embodiment, angle H may be 180 degrees. Accordingly, in one embodiment, the first and second tip portions  406 ,  410  may be spaced apart approximately 180 degrees, plus or minus 5 degrees, along a circumference of the needle body  402 . 
     The distinct distal end  404  configuration results in numerous advantages over the conventional needle tip. For example, by forming the first tip portion  406  longer than the second tip portion  410 , an increase in the surface area of cutting edges  422 - 428  extending between the tip portions  406 ,  410  is achieved. By increasing the effective cutting surface areas, the distal end  404  is able to maximize the amount of tissue to be harvested. The staggered configuration further ensures collection of a cohesive unit of sampled tissue. One of the drawbacks of current needle tip designs is that, as tissue is pierced and excised during tissue collection, the excised tissue may curl away from needle tip as it is advanced into the target tissue, resulting in a lost or incomplete sample. The staggered design is configured to overcome such a drawback. In particular, due to the staggered configuration, the leading first tip portion  406  is configured to initially pierce the tissue to be sampled prior to the following second tip portion  410 . Upon advancing the needle  400  further into the tissue, the first tip portion  406  is configured to direct a sample of tissue in a direction towards the lumen  403  of the needle  400 . As the needle  400  is forced further into the target tissue, the second tip portion  410 , which is set back from first tip portion  406 , is configured to catch and grab additional tissue that may have otherwise deflected off of the first tip portion  406  and may have missed the lumen  403  entirely, as is the case with some current needle tip designs. In this manner, a full core sample may be achieved. 
     The different embodiments of the biopsy needle of the present disclosure may be used in conjunction with minimally-invasive procedures, such as endoscopic procedures. For example, a biopsy needle consistent with the present disclosure may be compatible with an endoscopic biopsy device, such as needle biopsy delivery device configured for endoscopic ultrasound or endoscopic bronchial ultrasound procedures. For example, the biopsy needle may be compatible for use with exemplary endoscopic deliver systems and methods discussed in Needle Biopsy Device with Exchangeable Needle and Integrated Needle Protection, U.S. Pub. 2012/0116248, Rapid Exchange FNA Biopsy Device with Diagnostic and Therapeutic Capabilities, U.S. Pub. 2011/0190662, Device for Needle Biopsy with Integrated Needle Protection, U.S. Pub. 2010/0121218, and Needle Biopsy Device, U.S. Pub. 2010/0081965, the contents of each of which are hereby incorporated by reference in their entirety. 
     An exemplary embodiment of an endoscopic delivery device assembly for use with a biopsy needle of the present disclosure is illustrated in  FIG. 13 . The device and specific delivery methods are discussed in more detail in Needle Biopsy Device with Exchangeable Needle and Integrated Needle Protection, U.S. Pub. 2012/0116248, the contents of which are hereby incorporated by reference in their entirety. The device design consists of a handle mechanism (delivery system handle  10 ) and removable 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 system handle  10  further includes an inner handle member  10   d  disposed within the inner lumen of the middle handle member  10   b.    
     The delivery system handle  10  also incorporates a 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 needles, such as the biopsy needle previously described herein. The device design is modular in that the needle sub-assembly  15  can be detached from the proximal handle member  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 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 sheath  14  extension beyond the end of the endoscope accessory channel. 
     The needle sub-assembly  15  consists of at least a biopsy needle consistent with the present disclosure (e.g., needle  200 ). The body  202  of needle  200  can range in length from 200 mm up to 2500 mm. In some embodiments, the needle body  202  can range in length between 500 mm to 2000 mm. In some embodiments, the needle body  202  can range in length between 800 mm to 1800 mm. In some embodiments, the needle body  202  can range in length between 1640 mm to 1680 mm. The needle sub-assembly  15  further includes needle hub  17 , needle luer  18 , needle collet  226 , needle protector sub-assembly  9 , stylet hub  20 , and stylet shaft  22 . 
     As generally understood, the needle  200  itself can be manufactured from a variety of metallic based materials, including, but not limited to, nitinol, cobalt chrome, stainless steel, a metal alloy, combinations thereof, 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. It should be noted that the biopsy needle is not limited to any particular gauge (e.g., outer diameter). For example, depending on the type of sample to be collected, as well as the target site from which the sample is to be collected, the biopsy needle may range from 10-gauge to 30-gauge, and more specifically 15-gauge to 28-gauge, i.e., gauge 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 needles. 
       FIG. 14  is a drawing of the needle sub-assembly  15  of the device of  FIG. 13 . The needle sub-assembly  15  is inserted into and removed from the lumen of the delivery system handle  10  in acquiring tissue samples. The needle sub-assembly  15  consists of stylet hub  20  and stylet shaft  22  components which are securely locked on the needle luer  18  of the needle  200  via conventional internal luer threads, as generally understood by one skilled in the art. The stylet hub  20  may be attached to the stylet shaft  22  via any known processing techniques, including, but not limited to, adhesive bonding or insert injection molding. The female luer of the needle  200  incorporates a mating luer thread detail, onto which the stylet hub  20  may be tightened. The needle luer  18  element of the present disclosure 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 removable needle sub-assembly  15  also incorporates a needle collet  226 . The function of this needle collet  226  is to provide a means to center the needle body  202  in the sheath  14  of the delivery system during needle exchange and provide a mechanism for securing and locking the needle protector sub-assembly to the distal end  204  needle  200  once the needle  200  has been unlocked and withdrawn from the delivery system handle. The needle collet  226  of the present disclosure may be attached to a portion of the needle body  202  near the distal end  204  of the needle  200  by way of any known processing techniques, including, but not limited to, adhesive bonding, laser welding, resistance welding, insert injection molding, and combinations thereof. The needle collet  226  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. 
       FIG. 15  illustrates the needle protector sub-assembly  9  design embodiment of the present disclosure in the locked position at the distal end  204  of the needle  200 . The needle protector 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  24 . Alternatively, the 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 protector sub-assembly  9  also incorporates a needle protector (NP) hub O-Ring  25 . The O-Ring component resides in a recessed cut-out in the center of the assembled NP hub halves  23 . The NP hub O-Ring  25 , in conjunction with the needle collet  226 , which is securely attached to a portion of the needle body  202  near the distal end  204  of the needle  200 , provides a mechanism for locking the NP sub-assembly  9  onto the end of the needle  200 . In this way, the distal end  204 , including the first and second tip portions  206 ,  210  previously described herein, is protected, covered and shielded once the needle has been removed from the delivery system handle. For example, upon acquiring a sample from a target site, the needle  200  may be removed so as to gain access to the sampled material for testing and diagnostic procedures. The needle  200  may be continually withdrawn from the delivery system handle  10 , such that the needle collet  226  contacts the NP hub O-ring  25  and further pulls the NP sub-assembly  9  from engagement with needle hub  17 , such that the needle  200  is completely removed from the delivery system handle  10  and the NP sheath  24  encases the distal end  204  of the needle  200  to prevent inadvertent “needle sticking”. Further, an operator may then pull back the NP sub-assembly  9  from the distal end  204  of the needle  200  so as to collect the sampled material stored within the lumen of the needle  200 . Accordingly, the NP sub-assembly  9  is configured to translate along a length of the needle  200  so as to allow access to the distal end  204  of the needle  200  post acquisition and when the needle  200  is entirely removed from the delivery system handle  10 . 
     Referring the  FIG. 16 , the needle hub  17  embodiment of the needle sub-assembly is generally illustrated. The needle hub  17  provides a mechanism configured to lock the removable needle sub-assembly  15  into the delivery system handle  10  by means of the hub housing  27  and thumb latch  28  components and provide a means to lock the needle protector sub-assembly  9  embodiment shown in  FIG. 15 , into the delivery system handle  10 . As shown in  FIG. 16 , the needle hub  17  is securely attached to the needle luer  18  and needle body  202 . The needle hub  17  of the present disclosure may be attached to the distal end of the needle luer  18  via a number of processing techniques such as adhesive bonding or insert injection molding. 
     In some instances, it may be preferable to switch needles during a procedure, while still maintaining access to the target site. The delivery system of  FIG. 13  is configured to allow rapid needle exchanges without requiring the delivery system to be removed from the scope, as described in greater detail in U.S. Pub. 2012/0116248, the contents of which are hereby incorporated by reference in their entirety. Accordingly, the sheath  14  may remain at a target site for an indefinite period of time while allowing the exchange of multiple needles. The rapid needle exchange capabilities provided by the delivery system of the present disclosure may further decrease the amount of time required for a biopsy procedure, which may cut down the amount of anesthesia required during a particular procedure, improving patient safety. Additionally, a new biopsy device is not required for each needle, as may be the case with current biopsy devices and techniques. Accordingly, the delivery system and exchangeable needles of the present disclosure can cut down on costs and by preventing unnecessary waste. 
       FIG. 17  is a perspective view of a portion of the biopsy needle  200  near the distal end  204 . As shown, the needle  200  further includes needle collet  226  coupled to a portion of the needle body  202 . The length of the needle collet  226  may 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  226  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, depending on the gauge of the needle  200 . The needle collet  226  may be chamfered at the proximal and distal ends thereof. In some embodiments, it may be preferable that the chamfer angle of the needle collet  226  be in the range of 15 degrees to 80 degrees, oblique to a longitudinal axis of the needle  200 , but more preferably in the range of 30 degrees to 60 degrees. The chamfer on both ends of the needle collet  226  may provide smooth locking and unlocking with the needle protector sub-assembly  9  during needle exchanges. 
     The needle collet  226  is located at a set point distance from the distal end  204  of the needle  200 . The distance from the distal end  204  of the needle to the proximal collet position on the needle  200  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 more preferably is located 8 cm from the end of the needle  200 . This ensures that when the needle is extended to a maximum extension distance relative to the distal tapered end  14   a  of the sheath (i.e. 8 cm), the needle collet  226  does not exit the end of sheath  14 , as shown in  FIGS. 18A and 18B . 
     In the illustrated embodiment, a region  228  of the needle body  202  adjacent the distal end  204  may incorporate an embodiment to enhance the echogenic signature of the needle  200 . For example, this echogenically enhanced region  228  can be fabricated by, but not limited to, roughening the end of the needle over a pre-defined length adjacent to at least the first and second tip portions of the distal end  204 . The length of the echogenically enhanced region  228  may be in the range of 2 mm to 20 mm, but is more preferably in the range of 10 mm to 15 mm. The echogenic enhanced region  228  may be imparted to the needle body  202  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 other embodiments, the echogenically enhanced region  228  of the needle  200  may be 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. 
     It should be noted that other embodiments of a biopsy needle described herein, including needles  300  and  400 , may also include the needle collet  226  and/or one or more portions having echogenically enhanced regions  228 , as described with reference to needle  200 . 
       FIGS. 18A and 18B  are side views, partly in section, of storage and extension of the biopsy needle  200  of  FIG. 17  within the sheath  14  of the delivery system of  FIG. 13 . Referring to  FIG. 18A , the needle  200  is shown loaded within the sheath  14  with the device handle in the fully retracted position and ready for extension into a target site for sample collection. In this instance, the distal end  204  of the needle  200  lies proximal to the distal tapered end  14   a  of the sheath  14 .  FIG. 18B  illustrates the position of the needle  200  and needle collet  226  relative the sheath  14  when the needle transitions to a fully extended position, as indicated by arrow  230 . In the fully extended position, the needle collet  226  remains housed inside sheath  14 , proximal to the tapered distal tip, thereby preventing the needle  200  from extending past a set distance from the sheath  14 . 
     It is important that the needle  200  can be passed through an internal diameter of a sheath  14  of the delivery device without catching on an internal wall of same, particularly during tissue collection procedures or needle exchanges. As the needle advances, the heel of the back-cut grind  218  on the first tip portion  206 , for example, may come in contact with the internal diameter of the sheath  14  and reduce the friction between the distal end  204  of the needle  200 , particularly the point  208  of the first tip portion  206 , and the sheath  14 . In this way, the needle  200  can be smoothly tracked through the sheath to exit the end of the sheath. 
       FIGS. 19A-19C  are side views, partly in section, of the storage of needle  400  within the sheath  14  and extension of the needle  400  from the sheath  14  during a tissue collection procedure. In this embodiment, a stylet shaft  22  is shown positioned within the lumen  403  of the needle  400 . The inclusion of the stylet shaft  22  within the lumen  403  of the needle  400  may be advantageous during both storage of the needle  400  as well as extension of the needle  400 , as will be described in greater detail herein. As shown, the needle  400  may further include a needle collet  432  coupled to a portion of the needle body  402 . The needle collet  432  is similarly configured as needle collet  226 , previously described herein, and further functions in a similar manner. It should be noted that needle body  402  may further include one or more portions having echogenically enhanced regions, as previously described herein. 
     Referring to  FIG. 19A , the needle  400  is shown loaded within the sheath  14  with the device handle in the fully retracted position and ready for extension into a target site for sample collection. In this instance, the distal end  404  of the needle  400  lies proximal to the distal tapered end  14   a  of the sheath  14 . Further, the stylet shaft  22  is positioned within the lumen of the needle body  402 . As generally understood, the stylet  22  may include, but is not limited to, a removable coaxial thin wire configured to be passed within the lumen  403  of the needle body  402 . The stylet  22  may provide rigidity and stability to the needle  400  as well as the sheath  14 , particularly when manipulating the sheath  14  and needle  400  (e.g., maneuvering of the sheath  14  or needle  400  to a desired site for tissue collection). Accordingly, the stylet  22  can be manufactured from a variety of metallic based materials, including, but not limited to, nitinol, cobalt chrome, stainless steel, a metal alloy, combinations thereof, 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. 
     The stylet  22  is configured to further aid in the smooth passage of the needle  400  within the sheath  14 , particularly during extension of the needle  400  from the sheath  14 .  FIG. 19B  illustrates the position of the needle  400 , stylet  22 , and needle collet  432  relative the sheath  14  when the needle  400  transitions to an extended position, as indicated by arrow  434 . In the an extended position, the needle collet  432  remains housed inside sheath  14  and is sized so as to prevent the needle  400  from extending past a set distance from the sheath  14 . Furthermore, when the stylet  22  is in a loaded position, a distal end  21  of the stylet  22  is positioned at least flush with the distal end  404  (e.g., distal end  21  is positioned at or extending past the penetrating tip  408  of the leading first tip portion  406 ) so as to essentially prevent inadvertent catching of the penetrating tip  408  on the distal tapered end  14   a  of the sheath  14  during movement of the distal end  404  of the needle  400  through the distal tapered end  14   a  of the sheath  14 . Additionally, as the needle  400  advances, the heel of the back-cut bevel grind  420  on the leading first tip portion  406 , for example, may come in contact with the internal diameter of the sheath  14  and reduce the friction between the distal end  404  of the needle  400 , particularly the penetrating tip  408  of the leading first tip portion  406 , and the sheath  14 . In this way, the needle  400  can be smoothly tracked through the sheath  14  to exit the distal tapered end  14   a.    
     Furthermore, the stylet may be configured to protect the needle  400  from damage or inadvertent collection of a tissue sample. For example, as shown in  FIG. 19B , once the distal end  404  of the needle  400  is extended from the sheath  14 , the stylet  22  can remain in a loaded position (e.g., distal end  21  of the stylet  22  is positioned at or extending past the penetrating tip  408  of the leading first tip portion  406 ) until the clinician desires to begin tissue collection. In the illustrated embodiment, the distal end  21  of the stylet  22  is shown as having a rounded or blunt tip, so as to prevent puncturing of tissue. Accordingly, when in the loaded position, the stylet  22  prevents puncturing, excision, and subsequent collection of tissue within the needle  400 . As shown in  FIG. 19C , a clinician may subsequently withdraw the stylet  22  from the distal end  404  of the needle  400 , as indicated by arrow  436 , so as to expose the first and second tip portions  406 ,  410  for subsequent tissue collection. The stylet  22  may be moved to the loaded position at any time so as to prevent undesired tissue collection. 
     It should be noted that, in other embodiments, the stylet  22  may be used to initially puncture or penetrate a tissue to be collected. For example, in some embodiments, the distal end  21  of the stylet  22  may have a trocar pointed tip or other tip geometries configured to facilitate the introduction of the needle  400  into a tissue mass. Accordingly, the stylet  22  may be configured to aid the needle  400  in initially penetrating a tissue site, and, upon withdrawal of the stylet  22 , the needle  400  is then configured to collect tissue upon further advancement into the tissue. 
       FIG. 20  is a perspective view illustrating the initiation of sample tissue collection with biopsy needle  200 . It should be noted that biopsy needle  400  is configured to collect sample tissue in a similar manner as biopsy needle  200 , described in greater detail herein. Accordingly, the following description of sample tissue collection is not to be limited to biopsy needle  200 . As shown, the needle  200  may be extended from the sheath  14  when delivered to a target site. An operator (e.g., physician or other trained medical personnel) may then advance the distal end  204  of the needle  200  towards the target tissue  232  to be sampled (with or without the assistance of use of ultrasound techniques). As shown, because the first tip portion  206  extends further than the second tip portion  210 , the point  208  of the first tip portion  206  is configured to make initial contact and engage the tissue  232 , as indicated by arrow  234 . The first tip portion  206  is configured to pierce the tissue  232  and further direct a tissue sample  236  in a direction towards the lumen  203 , as indicated by arrow  238 . As the needle is forced further into the target tissue  232 , the second tip portion  210 , which is set back from the first tip portion  206 , is configured to catch and grab additional tissue that may have otherwise deflected off of the first tip portion  206  and may have missed the lumen  203  entirely, as is the case with some current needle tip designs. For example, as tissue is excised by the cutting edge  222  after initial puncture by the point  208  of the first tip portion  206 , the excised tissue may curl away from the first tip portion  206 . The second tip portion  210  is then configured to catch and collect the deflected excised tissue, as indicated by arrow  240 , and further pierce the target tissue  232 , thereby guiding a tissue sample  236  towards the lumen  203  and to be further excised by the cutting edge  222  upon contact therewith, as indicated by arrow  242 . In this manner, a full core sample may be achieved. In one embodiment, a vacuum may be communicated from the proximal end to the distal end  204  through the lumen  203  so as to provide a suction force to the target tissue  232  and further assist in collection and harvesting of the tissue sample via aspiration. 
     While several embodiments of the present disclosure have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the functions and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the present disclosure. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present disclosure is/are used. 
     Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclosure described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the disclosure may be practiced otherwise than as specifically described and claimed. The present disclosure is directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure. 
     All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms. 
     The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” 
     The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified, unless clearly indicated to the contrary. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications are possible within the scope of the claims. Accordingly, the claims are intended to cover all such equivalents. 
     INCORPORATION BY REFERENCE 
     References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. 
     EQUIVALENTS 
     Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.