Patent Publication Number: US-9408592-B2

Title: Biopsy device with aperture orientation and improved tip

Description:
FIELD OF THE INVENTION 
     Thee present invention relates generally to tissue removing devices such as biopsy devices and the methods of using such devices. More specifically, it is directed to an improved device and method for accessing and removing pathologically suspect tissue from within a patient&#39;s body. 
     BACKGROUND OF THE INVENTION 
     In diagnosing and treating certain medical conditions, such as potentially cancerous tumors, it is usually desirable to perform a biopsy, in which a specimen of the suspicious tissue is removed for pathological examination and analysis. In many instances, the suspicious tissue is located in a subcutaneous site, such as inside a human breast. To minimize surgical intrusion into the patient&#39;s body, it is desirable to be able to insert a small instrument into the patient&#39;s body to access the targeted site and to extract the biopsy specimen therefrom. 
     Electrosurgical techniques have been used in a variety of biopsy procedures. In electrosurgery, high frequency electrical energy is typically applied to patient tissue through an active electrode, the electrical circuit being completed by a return electrode in contact with the patent&#39;s tissue. Electrical energy flowing through the tissue from the active electrode is effective to ablate tissue near the active electrode, forming an opening in the tissue and so allowing insertion of the instrument into a patient&#39;s body. A return electrode may be placed on the exterior of the patient&#39;s body or may be incorporated into the device itself. The return electrode is typically attached to the patient at a point remote from where the primary or active electrode contacts the tissue. However, in the case of a bipolar electrode for example, the return electrode may be disposed near to the active electrode. An electrosurgical biopsy instrument is disclosed and claimed in U.S. patent application Ser. No. 09/159,467 for “Electrosurgical Biopsy Device and Method,” now U.S. Pat. No. 6,261,241, assigned to the assignee of the present application, and which is hereby incorporated by reference in its entirety. A variety of needle like tip designs have been developed to aid in the accessing of intracorporeal sites for biopsy and other procedures. Electrosurgical techniques have also been used in a variety of biopsy procedures to gain access to an intracorporeal site. See for example U.S. Pat. No. 6,261,241, assigned to the assignee of the present application, and which is hereby incorporated by reference in its entirety. 
     The prior needle like tips do not always allow proper placement of the biopsy or other surgical device. Moreover, while the electrosurgical biopsy devices have been found to be effective in many instances, they are not suitable for use in conjunction with magnetic resonance imaging. 
     While these electrosurgical biopsy devices have been found to be effective in many instances, they may not always be suitable for use in conjunction with magnetic resonance imaging. 
     SUMMARY OF THE INVENTION 
     This invention is directed to devices for accessing and severing tissue from a target site within a patient and methods for utilizing such devices. The devices embodying features of the invention provide access to a targeted tissue site within a patient and provide for the selection, separation and capture of a tissue specimen from supporting tissue at the targeted site. 
     A tissue accessing and severing device and system having features of the invention generally include an elongated, preferably disposable probe component having a plurality of operative elements and a driver component configured to receive the elongated probe component and drive the various operative elements of the probe component. 
     The elongated probe component has a distal shaft portion with a tissue penetrating distal tip, a tubular section proximal to the distal tip, an inner lumen extending within the tubular section and an open, tissue receiving aperture in the tubular section which provides access to tissue at the targeted site. The probe component includes an elongated tissue-cutting member, which is preferably at least in part cylindrically shaped. The tissue cutting member is provided with at least one tissue cutting edge which is configured to sever tissue extending into the interior of the tubular section through the aperture thereof. The cutting edge on the tissue cutting member may be configured for longitudinal cutting movement and may include oscillating rotational motion and/or reciprocating longitudinal motion to sever specimen tissue extending through the aperture from supporting tissue at the targeted site. The cutting surfaces or edges are radially spaced from a longitudinal axis of the probe component and are generally transversely oriented with respect to the longitudinal axis. The tissue cutter is preferably slidably disposed within the inner lumen of the tubular section, although it may be disposed about the tubular section. The probe component may also have a handle which releasably engages the driver component. 
     In one embodiment of the invention, the cutting member has an inner lumen preferably extending to the proximal end thereof for tissue specimen removal. While mechanical withdrawal of the tissue specimen may be employed, it is preferred to provide a vacuum within the cutting member from the proximal end of the cutting member. The proximal end of the cutting member may be configured to be in fluid communication with a vacuum source to aspirate the severed tissue specimen through the inner lumen of the cutting member to a tissue collection station. A higher fluid pressure may be maintained in the inner lumen of the cutting member distal to the tissue specimen to aid in transporting the specimen proximally through the inner lumen. In this manner, the mechanical withdrawal and/or the vacuum on the proximal end of the specimen and a higher pressure on the distal end of the specimen can move the specimen through the inner lumen of the cutting member to a tissue collection station. 
     In at least one embodiment, the handle of the probe component is secured, preferably releasably secured, to the driver housing provided to operably connect the various operative elements of the probe with operative elements of the driver component. The tissue cutting member is operatively connected to at least one driver to provide the desired cutting motion. The proximal end of the tubular section is rotatably secured within the handle housing so that the orientation thereof with respect to the longitudinal axis and therefore the orientation of the tissue receiving aperture within the tubular section, can be selected. The orientation of the aperture may be selected manually such as described in copending application Ser. No. 10/642,406, filed Aug. 15, 2003 or it may be preset or selected electronically by a control module which also controls the operation of the cutting member and electrical power. The aperture orientation setting may be selected before or after the distal portion of the probe component is inserted into the patient. 
     The tissue penetrating distal tip embodying features of the invention has a proximal base secured to the distal end of the probe shaft of the biopsy device, and a sharp distal point distal to the proximal base. The tissue penetrating distal tip has a first concave surface extending from the base to the sharp distal point. The distal tip also has a second concave surface, which intersects the first concave surface forming therewith a first curved cutting edge that leads to the sharp distal point. The distal tip also has a third concave surface which intersects the first concave surface forming therewith a second curved cutting edge leading to the sharp distal point and also intersects the second concave surface forming therewith a third curved cutting edge that leads to the sharp distal point. The concave surfaces preferably have center lines which extend from the proximal base of the distal tip to the sharp distal point. In a presently preferred embodiment the concave surfaces are of the same area. However, they may have different areas. 
     The driver component has at least two and preferably three driver units for operating the probe component secured to the driver component. Specifically, the driver component has a first driver unit for rotating the tubular section of the probe component, a second driver unit for moving the cutting member along a longitudinal axis of the cutting member and optionally a third driving unit for rotating or oscillating the cutting member about the longitudinal axis. The first driver unit rotates the tubular section of the probe component, preferably in discrete steps, so that the location of the tissue receiving aperture in the distal extremity of the tubular section can be selected prior to or during the procedure. The discrete rotational steps of the tubular section are preferably in 30° or multiples thereof so that the rotational movement will follow 12 hour clock markings. Preferably, the second and third driver units are operable together so that the cutting member may rotate or oscillate about a longitudinal axis as the cutter member is moved longitudinally. This allows a rotation or an oscillation of the cutter during the cutting process which can aid in cutting tissue. 
     The driver component may have one or more light sources in a distal portion thereof to illuminate the accessing site during the procedure. 
     A method of cutting and collecting a tissue specimen with a tissue collection device embodying features of the invention includes advancing such a device at least partially into tissue at a desired site within the patient&#39;s body with the tissue penetrating distal tip of the outer cannula disposed distal to the tissue specimen to be separated from the target site. A vacuum is established within the inner lumen of the tubular section to draw tissue through the aperture therein into the inner lumen of the tubular section. The cutting member, which is slidable disposed within the inner lumen of the tubular section, may then be moved longitudinally to cut a tissue specimen from supporting tissue at the target site by the longitudinal motion, which preferably includes oscillating rotational movement and/or reciprocating longitudinal movement. The vacuum established within the inner lumen of the tubular section may be applied through the inner lumen of the tissue cutting member when the tissue cutting member is disposed within the tubular section. The applied vacuum within the inner lumen of the tissue cutting member, may also be utilized to pull or aspirate the separated tissue sample proximally. In addition, or alternatively, a higher fluid pressure may be maintained in a distal part of the inner lumen of the tubular section, distal to the specimen, to push the tissue specimen proximally, Alternatively, the tissue specimen may be mechanically withdrawn. Fluid pressure may include pressure from a liquid delivered into the interior of the device, such as a physiological saline solution, and may include a gas, such as pressurized carbon dioxide, nitrogen or air, delivered into the interior of the device. Access to ambient air can also maintain a sufficiently high pressure differential to move the specimen through the inner lumen of the cutting member. Anesthetic may be injected to the target site through the outer cannula or the inner lumen of the cutting member. Upon removal from the patient, the tissue specimen may then be subjected to pathological examination. After acquisition of a tissue specimen or specimens, the tissue separation system may be repositioned for further tissue separation and collection or it may be withdrawn from the patient. 
     The tubular section of the probe provides the support for the probe to enable precise location of the accessing port to the desired location at the target site with its radial orientations being preset before the device is introduced into the patient or selected after the tubular section is disposed within the patient. The cutting member quickly and cleanly severs the tissue specimen drawn into the interior of the tubular section though the aperture by the action of the vacuum or otherwise. Upon removal of the tissue specimen, the tissue receiving aperture may be radially repositioned about the longitudinal axis of the tubular section of the probe component so that a plurality of specimens may be taken from the target site. The orientation of the tissue receiving aperture during the procedure may follow a preselected pattern or may be selected by the physician for other selected tissue specimens. 
     A tissue acquisition system assembly embodying features of the invention may include a device for delivery of one or more marker bodies through a tubular member of a biopsy device such as the tubular cutting member. Such a marker delivery device includes an elongated shaft having an inner lumen and a discharge opening in a distal portion of the elongated shaft, at least one marker body which is disposed within the inner lumen of the elongated shaft, a pusher element which is slidably disposed within the delivery device and which is configured to urge at least one marker body out the discharge opening in the distal portion of the elongated shaft. The marker delivery device has a distally flared guide member which is slidably disposed on the elongated shaft to guide the distal portion of the elongated shaft into a proximal end of the tubular member of a biopsy device. This invention is directed to a tissue penetrating probe tip, particularly for biopsy devices. These devices provide access to a targeted tissue site and provide for the separation and capture of a tissue specimen from supporting tissue at the targeted site. 
     These and other advantages of the invention will become more apparent from the following detailed description of the invention and the accompanying exemplary drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of the elongated tissue biopsy system embodying features of the invention. 
         FIG. 2  is a perspective view of the embodiment shown in  FIG. 1  in an assembled condition without a housing cover for the probe component. 
         FIG. 3  is a side elevational view of the tissue biopsy device shown in the  FIG. 2 . 
         FIG. 4A  is a longitudinal cross-section of the probe shown in  FIG. 3  taken along the lines  4 - 4  with the tissue cutting element in a withdrawn position. 
         FIG. 4B  is a longitudinal cross-section of the probe shown in  FIG. 3  taken along the lines  4 - 4  with the tissue cutting element in a forward or closed position. 
         FIG. 5  is a transverse cross-sectional view of the probe shown in  FIG. 4B  taken along the lines  5 - 5 . 
         FIG. 6  is a perspective view of the underside of the probe shown in  FIG. 1 . 
         FIG. 7  is an enlarged perspective view of the distal end of the driver unit shown in  FIG. 1 . 
         FIG. 8  is an enlarged perspective view of the distal end of the probe housing illustrating a marker element which depicts the orientation of the aperture in the tubular section of the biopsy device. 
         FIG. 9  is a perspective view of the underside of the driver shown in  FIG. 1 . 
         FIG. 10  is an elevational view of a tissue penetrating tip embodying features of the invention. 
         FIG. 11  is a perspective view of the underside of the tip shown in  FIG. 10 . 
         FIG. 12  is a longitudinal, center line cross-sectional view of the penetrating tip shown in  FIG. 10 . 
         FIG. 13  is a longitudinal cross-sectional view of the penetrating tip shown in  FIG. 12  taken along the lines  13 - 13 . 
         FIG. 14  is a longitudinal cross-sectional view of the penetrating tip shown in  FIG. 12  taken along the lines  14 - 14 . 
         FIG. 15  is a longitudinal cross-sectional view of the penetrating tip shown in  FIG. 3  taken along the lines  15 - 15 . 
         FIG. 16  is a bottom view of the penetrating tip shown in  FIG. 10 . 
         FIG. 17  is a transverse cross-sectional view of the penetrating tip shown in  FIG. 16  taken along the lines  17 - 17 . 
         FIG. 18  is a transverse cross-sectional view of the penetrating tip shown in  FIG. 16  taken along the lines  18 - 18 . 
         FIG. 19  is a transverse cross-sectional view of the penetrating tip shown in  FIG. 16  taken along the lines  19 - 19 . 
         FIG. 20  is a transverse cross-sectional view of the penetrating tip shown in  FIG. 16  taken along the lines  20 - 20 . 
         FIG. 21  is a perspective view of the tissue biopsy system shown in  FIG. 1  assembled and mounted on a stereotactic frame. 
         FIG. 22  is an elevational view of a marker delivery device with a flared guide on the distal end of the shaft which facilitates guiding the distal tip of a marker delivery device into the interior of the proximal end of the tissue cutter. 
         FIG. 23  is a longitudinal cross-sectional view of the distal end of the marker delivery device and flared guide disposed within the tissue collection component shown in  FIG. 1 . 
         FIG. 24  is a longitudinal cross sectional view of the proximal end of the marker delivery device with the flared guide at the proximal end of the shaft and with the shaft deployed within the inner lumen of the tissue cutter. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
       FIGS. 1-3  illustrate a biopsy system  10  embodying features of the invention which includes a disposable probe component  11 , a driver component  12  and specimen collector  13 . 
     The probe component  11  generally includes an elongated distal shaft  14  having a tubular section or cannula  15  with a tissue penetrating tip  16  on the distal end thereof and an open, tissue receiving aperture  17 . The probe component  11  also includes a probe housing  18  with a housing cover  19  which is configured to interfit with the driver component  12 . A tissue cutter  20  is slidably disposed within the probe and has a distal cutting surface  21  which severs tissue which extends through the tissue receiving aperture  17 . 
     Details of the probe component  11  are further shown in  FIGS. 4A and 4B . The probe housing  18  has a mechanical system for rotating the housing and the tubular section  15  secured thereto to control the angular position of the tissue receiving aperture  17  and for moving the tissue cutter  20  slidably disposed within the probe component  11 . 
     The mechanical system of the driver component  12  has first driving gear  22  that is configured to engage the probe gear  23  and rotate the probe housing  18  so as to adjust the orientation of aperture  17  in the distal extremity of the tubular section  15 . The probe gear  23  is secured to the rotating connector body  24  by adhesive  25 . The proximal extremity of the tubular section  15  is secured to the rotating connector body  24  by adhesive  26 . An end cap  27  retains the connector body  24  within the probe housing  18 . Rotation of the probe gear  23  rotates the connector body  24  and the attached tubular section  15 . The rotation is preferably controlled so that the tubular section  15  rotates in discrete steps about the longitudinal axis  28  to adjust the angular orientation of the aperture  17  about the longitudinal axis. Preferably these discrete orientations may be provided in increments of 30° which can be readily indicated by arrow  29  at the distal end of the probe housing  18  as shown in  FIG. 8 . 
     The second driving gear  30  is configured to drive the tissue cutter  20  longitudinally. The driving gear  30  engages probe gear  31  which drives cutter traverse nut  32  and cutter screw  33  threadably connected to the cutter traverse nut. The distal end of the cutter screw  33  is provided with a recess  34  which receives the rib  35  of the cutter shuttle  36 . The cutter shuttle  36  is secured to the tissue cutter  20  by adhesive  37 . The probe gear  31  is secured to the cutter traverse nut  32  by adhesive  38 . Rotation of the probe gear  31  adjusts the relative axial position of the cutter screw  33  with respect to the cutter traverse nut  32  which is secured to the cutter shuttle  36 . Longitudinal movement of the tissue cutter  20  follows the longitudinal movement of the cutter shuttle  36  resulting from the movement of cutter screw  33 . The length of the tissue receiving aperture  17 , and as a result the length of the specimen, can be controlled by adjusting the initial longitudinal position of the distal end of the tissue cutter  20  within the aperture, before cutting. 
     The third driving gear  40  is configured to rotate or oscillate the tissue cutter  20  as the cutter moves along the longitudinal axis  28  to facilitate the cutting action of the cutting surface  21  on the distal end of the cutter. The third driving gear  40  engages probe gear  41  which is secured to cutter oscillation shaft  42  by adhesive  43 . The probe gear  41  may be oscillated back and forth about the longitudinal axis  28  or rotated continuously in a single direction about the longitudinal axis, or both depending upon the desired rotational movement of the tissue cutter. 
     A biased valve assembly  44  is provided in the distal end of the probe housing  18  to ensure sealing when a vacuum is developed within the interior  45  of the tissue cutter  20  while providing an atmospheric vent  46  between the interior surface  47  of the tubular section  15  and the exterior surface  48  of the tissue cutter  20 . The valve assembly  44  includes a spring  49 , valve body  50  and a valve collar  51  which is secured to the proximal end of the tubular section  15  by adhesive  52 . The proximal end of the valve spring  49  rests against the shoulder  53  provided in the exterior of the valve body  50 . A biased cutter shaft seal  54  slidably engages the exterior  48  of the tissue cutter  20 . 
     The tissue specimen collector  13  is secured to the proximal end of the housing of probe component  11  and has an interior  55  in fluid communication with the inner lumen  56  extending within the tissue cutter  20  and has a removable proximal wall  57  of specimen receiving cartridge  58  which gives access to the interior  55  and any tissue specimens which may have been drawn therein. A vacuum is generated within the interior  55  to draw tissue specimens through the inner lumen  45  into the interior  55 . Tubular member  59  has a distal end which is in fluid communication with the interior  55  of the tissue specimen collector  13  and has a proximal end (not shown) which is configured to be connected to a vacuum source. Application of a vacuum within the tubular member  59  aids in pulling tissue into the interior  17  of the tubular section  15  and transfer of the severed tissue specimen through the inner lumen  45  of the tissue cutter  20  to the specimen cartridge  58 . 
     The driver  12  has a housing  60  with an upper concave surface  61  which is configured to receive the lower surface  62  of the probe housing  18 . Three partially exposed driving gears  22 ,  30  and  40  are provided on the proximal end of the driver  12  which are configured to engage the probe gears  23 ,  31  and  41  respectively. The drive  12  is provided with three separately operating drive motors (not shown) which drive the drive gears  22 ,  30  and  40 . The separate drive motors (not shown) are connected to and the operation thereof controlled by a control module, such as described in copending application Ser. No. 10/847,699, filed on May 17, 2004. The control module controls the motors which move the individual drive gears  22 ,  30  and  40 . The gear  22  engages gear  23  in the probe  11  to control the rotation of the probe housing  18  and the location and orientation of the tissue receiving aperture  17 . The drive gear  30  engages probe gear  31  to control the longitudinal position and motion of the tissue cutter  20  along the longitudinal axis  28 . Drive gear  40  engages probe gear  41  to control the oscillation or rotation of the tissue cutter  20  about the longitudinal axis  28 . 
     As shown in  FIG. 7 , the front face of the driver component  12  is provided with light sources  66  and  67  and a manually activatable switch  68  to activate the light sources and enable the physician and other operating personnel to better view the operating site on the patient. Other manual switches, e.g. a foot activated switch, may be employed. Alternatively, the light sources may be automatically activated when the probe component  11  is installed on the driver  12  or other events such as when electrical power is turned on. The driver component  12  may have a battery pack for the light sources  66  and  67 . 
     The tissue penetrating distal tip  16  may have a variety of tip shapes. A particularly suitable distal tip embodying features of the invention is shown in  FIGS. 9-20 . The tissue penetrating distal tip generally includes a base  70 , a sharp distal point  71 , a first concave surface  72 , a second concave surface  73  and a third concave surface  74 . 
     The intersection between the first concave surface  72  and the second concave surface  73  forms the first curved cutting edge  75 . The intersection between the second concave surface  73  and the third concave surface  74  forms the second curved cutting edge  76 . The intersection between the third concave surface and the first concave surface  72  forms the third curved cutting surface  77 . 
     The concave surfaces  72 ,  73  and  74  are hollow ground and the pentrating tip  16  is then electro-polished to increase the sharpness of the cutting edges  75 ,  76  and  77 . The penetrating distal tip  16  may be formed of suitable surgical stainless steel such as  17 - 4  stainless steel. Other materials may be suitable. The penetrating distal tip  16  is preferably electro-polished in an acidic solution to sharpen the curved cutting edges and thereby facilitate tissue penetration. Suitable electro-polishing solutions include Electro Glo sold by the Electro Glo Distributing Co. 
     The base  70  of the tissue penetrating tip  16  may be secured to the distal end of the elongated shaft of the biopsy device  10  for accessing and collecting tissue from a target site within a patient. The sharp distal tip  16  embodying features of the invention readily penetrates a patient&#39;s tissue, particularly breast tissue and facilitates guiding the distal end of the biopsy or other device to a desired intracorporeal location. 
     The tissue penetrating tips may also be employed on biopsy devices such as those described in co-pending application Ser. No. 10/642,406, filed on Aug. 15, 2003, which is assigned to the present assignee. Alternatively, the distal tip may be provided with an arcuate RF electrode such as disclosed in U.S. Pat. Nos. 6,261,241, and 6,471,700, both assigned to the present assignee. 
     The separate driver component  12  allows the probe unit  11  to be disposable. The drive gears of the drive component  12  control the motion of the tissue cutting member  20  for cutting and the motion of the tubular section  15  to orient the aperture  17 . Other means (not shown) may provide mechanical and electrical power, vacuum, and control to the probe device. Examples of replaceable snap-in type probe units are disclosed in Burbank et al., U.S. patent application Ser. No. 10/179,933, “Apparatus and Methods for Accessing a Body Site”. Drive units such as that described in WO 02/069808 (which corresponds to co-pending U.S. application Ser. No. 09/707,022, filed Nov. 6, 2000 and U.S. application Ser. No. 09/864,021, filed May 23, 2001), which are assigned to the present assignee, may be readily modified by those skilled in the art to accommodate the movement of the cutting member  20 . 
     In use, the distal end of the probe component  11  is advanced within the patient with the tissue cutter  20  in a forward or closed position ( FIG. 4B ), until the aperture  17  of the tubular section  15  is located in a desired location for taking a tissue specimen. The tissue cutter  20  is then withdrawn proximally to an open position to open the aperture  17 . The withdrawal of the tissue cutter can be used to control the length of the aperture which is opened in order to control the length of the specimen which is severed. A vacuum is applied to the interior  45  of the tissue cutter  20  to draw tissue at the site into the inner lumen of the tubular section  15  through the aperture  17 . The tissue cutter  20  is then driven distally by rotation of probe gear  30  and rotated or oscillated by drive gear  40  engaging probe gear  41  to sever the aspirated tissue from the supporting tissue at the target site with the tissue cutting surface  21 . The vacuum within the interior of the tissue cutter  20  causes the tissue specimen to be drawn through the inner lumen  45  of the tissue cutter  20  and into the cartridge  58  of specimen collector  13  shown in  FIG. 2 . Positive pressure or even ambient conditions distal to the tissue specimen can facilitate tissue passing through the interior  45  of tissue cutter  20 . If another tissue specimen is desired, the tubular section  15  may be rotated by the drive gear  22  engaging the probe gear  23  in one or more steps to repeat obtaining another tissue specimen in the same manner without otherwise moving the probe component  11 . Typically, a first tissue specimen is obtained with the aperture  17  of the probe  11  in the 12 o-clock position, the second at the 3 o-clock position, the third at the 9 o-clock position and the fourth at the 6 o-clock position. The location of the second and third specimens may be reversed. The position of the aperture  17  may be indicated by a marker arrow  29  at the end cap  27  so that the physician or other operating personnel can readily determine what the orientation of the aperture  17  within the patient. 
     The biopsy system  10  may be hand held for some biopsy procedures or the system may be mounted on a stereotactic mounting stage  80  as shown in  FIG. 21 . A shoe  81  is slidably mounted to a rail  82  of a Fisher stage. The mounting member  83  is secured to the shoe  81  by a threaded post (not shown) secured to thumbwheel  84 . As shown in  FIG. 10 , the bottom surface  85  of the driver component  12  is configured to conform at least in part to the upper surface of the mounting member  83 . The sampling and vacuum switches  86  and  87  respectively on the driver component  12  are actuated by the optional sampling and vacuum actuating elements  88  and  89  on the mounting member  83 . Alternatively, sampling and vacuum may be actuated with a foot pedal. As shown in  FIG. 22 , the driver component has an operator dial  90  which when turned opens a threaded hole  91  for receiving a threaded post (not shown) secured to the thumbwheel  84  and the locating pin holes  92  and  93  which receive the complementary posts (not shown) in the mounting member  83 . 
     As mentioned above, positive pressure or even ambient conditions will aid in passing the severed tissue specimen through the inner lumen  45  of tissue cutter  20  into the cartridge  58  of specimen collector  13 . As shown in  FIGS. 4A and 4B  venting valve can provide ambient pressure behind the tissue specimen in the cutter interior  45  from the interior of the tubular section  15 . The valve body  50  is opened for atmospheric venting when the tissue cutter  20  is in the forward position upon the completion of severing the specimen from the tissue site. However, when the tissue cutter  20  is pulled back proximally the valve spring  49  urges the valve body  50  back to a closed position. While the tissue cutter  20  is shown with a tissue cutting surface  21  which is perpendicular to the longitudinal axis  28 , the tissue cutting surface may be at an angle or even parallel to the longitudinal axis as described in co-pending application Ser. No. 10/642,406, filed Aug. 15, 2003. 
     The distal cutting edge  21  of the tissue cutter  20  may initially be located proximal to the aperture  17  to provide a full aperture for receiving tissue or it can be initially located within the aperture  17  in order to control the length of the specimen. The cutting action of tissue cutter  20  preferably continues until the beveled cutting surface  21  has completely traversed the aperture  17  to ensure that the tissue drawn through the aperture is completely severed from supporting tissue at the biopsy site. A vacuum may be applied to aspirate the severed tissue specimen through the inner lumen of the tissue cutter  20  to the cartridge in the specimen collector at the proximal end of the biopsy device. Positive pressure or access to ambient conditions may be provided in the distal end of the tubular section to aid in the specimen transfer. 
     After the removable wall  57  of the specimen receiving cartridge  58  is removed and the specimens therein removed, it is frequently desirable to deliver one or more markers to the target site from which the specimens have been removed. Such marker delivery devices are shown in co-pending application Ser. No. 10/753,694, filed on Jan. 7, 2004 and co-pending application Ser. No. 10/444,770, filed May 23, 2003. However, the distal ends of these marker delivery devices are very small and they can be difficult to insert into the proximal end of the tissue cutter  20  which is just slightly larger to accommodate the marker delivery shaft. 
       FIG. 22  illustrates a marker delivery device  100  which is particularly suitable to facilitate the introduction of the distal end of the shaft  101  into the inner lumen  45  of the tissue cutter  20  and the advancement therein. As shown in  FIG. 23 , to facilitate the insertion of the small diameter distal tip  101  of the marker delivery device  100  into the slightly larger inner lumen  45  of the tubular cutter  20  at its proximal end, the distal tip is preferably provided with an outwardly flared guide  102  which is slidably mounted on the shaft  103  of the marker delivery device  100 . The proximal end of the tubular cutter  20 , the flared guide  102  and/or the distal tip  101  may be provided with mating guide elements which orient the marker delivery device with the cannula  15  of the biopsy device. To ensure that one or more markers are discharged through the aperture  17  of the biopsy device  10  when the pusher element slidably disposed within the delivery device is urged distally to press at least one marker body out the discharge opening in the distal portion of the elongated shaft of the marker delivery device. As indicated in  FIG. 23 , the shaft  103  of the marker delivery device  100  is advanced into the inner lumen  45  of the tissue cutter  20  so that the distal end  101  of the marker delivery device  100  is adjacent to the aperture  17  of the cannula  15 . Plunger  104  is pressed further into the inner lumen of shaft  103  to eject one or more markers  105  through the aperture  17  in the tubular section  15  before the biopsy device  10  is removed from the patient. The delivery of markers to the target site after specimen removal, while the distal end of the biopsy device is still at the biopsy site, ensures that the markers are properly position at the biopsy site. 
     While the slidably mounted, flared proximal guide  102  is described with respect to being disposed on the shaft  103  of marker delivery device  101 , the flared guide  102  has wide application within a variety of biopsy and other devices where one small diameter tubular member is to be inserted into a slightly larger, but still small diameter second tubular member. 
     The elongated probe component  11  of the biopsy system  10  has a length of about 3 to about 20 cm, preferably, about 5 to about 13 cm, and more specifically, about 8 to about 9 cm for breast biopsy use. To assist in properly locating the probe  11  during advancement thereof into a patient&#39;s body, the distal extremity of the tubular section may be provided with a marker at a desirable location that provide enhanced visualization by eye, by ultrasound, by X-ray, MRI or other imaging or visualization means. Manual palpation may also be employed. An echogenic polymer coating that increases contrast resolution in ultrasound imaging devices (such as ECHOCOAT™ by STS Biopolymers, of Henrietta, N.Y.) is suitable for ultrasonic visualization. Radiopaque markers may be made with, for example, stainless steel, platinum, gold, iridium, tantalum, tungsten, silver, rhodium, nickel, bismuth, other radiopaque metals, alloys and oxides of these metals. In addition, the surfaces of the device in contact with tissue or other components of the device may be provided with a suitable lubricious coating such as a hydrophilic material or a fluoropolymer. 
     The tubular section and the tissue cutter are preferably formed of a surgical grade stainless steel. However, other high strength materials such as MP35N, other cobalt-chromium alloys, NiTi alloys, ceramics, glasses, and high strength polymeric materials or combinations thereof may be suitable. 
     A patient&#39;s skin usually must be breached in order to gain access to a body site where a tissue specimen is to be obtained. A scalpel or other surgical instrument may be used to make an initial incision in the skin. After the specimens have been taken, the biopsy device may be removed from the patient. The entire device may be removed; however, in some embodiments, the cartridge  58  may be removed from the system  10  and a delivery cannula may be inserted through the inner lumen of the cutter  20  to deliver markers to the biopsy site through the aperture  17 . In addition, it will be readily appreciated that other types of instruments may be inserted into the tissue site through the tissue cutter in addition to or in place of the instruments described above. Moreover, therapeutic or diagnostic agents may be delivered through the tissue cutter  20  or the tubular section  15 . 
     While particular forms of the invention have been illustrated and described herein, it will be apparent that various modifications and improvements can be made to the invention. For example, while the various embodiments of the invention have been described herein in terms of a biopsy device, it should be apparent that the devices and methods of utilizing the device may be employed to remove tissue for purposes other than for biopsy, i.e. for treatment or other diagnoses. Additionally, the tissue penetrating distal tip design may be employed on probes for other uses. Other modifications include, for example, a tissue cutter slidably mounted around the tubular section of the probe component rather than within the tubular section. Moreover, individual features of embodiments of the invention may be shown in some drawings and not in others, but those skilled in the art will recognize that individual features of one embodiment of the invention can be combined with any or all the features of another embodiment. Accordingly, it is not intended that the invention be limited to the specific embodiments illustrated. 
     Terms such a “element”, “member”, “device”, “section”, “portion”, “means”, “step” and words of similar import, when used in the following claims, shall not be construed as invoking the provisions of 35 U.S.C. §112(6) unless the claims expressly use the term “means” followed by a particular function without specific structure or the term “step” or “steps” followed by a particular function without specific action. All patents and patent applications referred herein are incorporated by reference in their entirety.