an apparatus is provided herein for deployment of a marker . the marker is delivered by way of a lumen , such as the working channel of a biopsy device or through the channel formed when performing a biopsy . according to several exemplary embodiments discussed below , the marker deployment device includes an elongated introduction device and a deployment assembly . the deployment assembly deposits the marker through an aperture , and then at least substantially closes the aperture . maintaining the aperture in a substantially closed position reduces the possibility that the marker will fall back into deployment device . in the following description , for purposes of explanation , numerous specific details are set forth in order to provide a thorough understanding of the present method and apparatus . it will be apparent , however , to one skilled in the art that the present method and apparatus may be practiced without these specific details . reference in the 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 . the appearance of the phrase “ in one embodiment ” in various places in the specification are not necessarily all referring to the same embodiment . fig1 illustrates a marker deployment device ( 100 ) coupled to a working channel ( 110 ), such as the working channel of a biopsy device according to one exemplary embodiment . the working channel ( 110 ) has an aperture ( 120 ) defined therein . the deployment device ( 100 ) according to the present exemplary embodiment may include a hub ( 130 ) to which a cannula ( 131 ), ( as best seen in fig2 ) is connected . the cannula is selectively received within the working channel ( 110 ). the deployment device ( 100 ) also includes a push rod ( 140 ), which extends into the hub ( 130 ). in fig1 , a relatively large portion of the hub ( 130 ) is shown in contact with the proximal end of the working channel ( 110 ). this contact prevents further movement of the deployment device ( 100 ) within the working channel ( 110 ). as the movement and location of the deployment device ( 100 ) is thus constrained , the push rod ( 140 ) may then be advanced to deploy a marker . the proximal end of the push rod ( 140 ) may include a plunger ( 141 ) that is relatively large compared to the rest of the push rod ( 140 ), plunger ( 141 ) which may facilitate movement of the push rod ( 140 ) relative to the working channel ( 110 ) as the deployment device ( 100 ) is actuated . other components of the deployment device ( 100 ) will be discussed in isolation with reference to fig2 , while the operation of the deployment device ( 100 ) will be discussed further with reference to fig3 a - 3b . fig2 illustrates a distal end ( 212 ) of the deployment device ( 100 ) in more detail . as used herein , the distal end shall refer to a portion nearer the biopsy site while proximal shall refer to the end opposite the distal end . as shown in fig2 , the marker deployment device ( 100 ) includes the cannula ( 131 ), the push rod ( 140 ), and an expandable member ( 200 ). the expandable member ( 200 ) forms a deployment assembly . the deployment assembly is configured to deposit a marker ( 210 ) while minimizing space between the deployment device ( 200 ) and the device or area used to introduce the deployment device . further as seen in fig2 , the distal end ( 212 ) of the cannula ( 130 ) is open . the distal end of the push rod ( 140 ) is coupled to the expandable member ( 200 ). consequently , translation of the push rod ( 140 ) relative to the cannula ( 131 ) results in movement of the expandable member ( 200 ) relative to the cannula ( 131 ). the expandable member ( 200 ) is configured to receive a marker ( 210 ). in particular , the expandable member ( 200 ) may be compressed by a predetermined amount to form a depression ( 214 ) appropriately sized such that the marker ( 210 ) may be received therein . fig2 illustrates the push rod ( 140 ), expandable member ( 200 ), and marker ( 210 ) retained within the cannula ( 131 ) at a first , pre - deployment position . in this first position , the expandable member ( 200 ) may be compressed within the cannula ( 131 ). as introduced , according to one exemplary embodiment , the deployment device ( 100 ) is delivered through the working channel ( 110 ) of a biopsy device or other surgical device . in particular , the cannula ( 131 ) is sized to slide relative to the working channel of the biopsy device . thus , the distal end ( 212 ) of the deployment device ( 100 ) may be introduced to the proximal end of the working channel ( 110 ). as the deployment device is urged toward the distal end of the working channel ( 110 ), the push rod ( 140 ), the expandable member ( 200 ), and the marker ( 210 ) are maintained in their first position relative to the cannula ( 131 ). the distal end of the deployment device ( 100 ) is urged toward the distal end of the working channel ( 110 ) a predetermined distance . in one embodiment , the hub ( 130 ) comes into contact with the proximal end of the working channel ( 110 ) to serve as a stop member to define the predetermined distance . as hub ( 130 ) comes into contact with the proximal end of the working channel ( 110 ), the cannula ( 131 ) is prevented from advancing further . with the location of the cannula ( 130 ) thus constrained , the push rod ( 140 ) may be actuated to deploy the marker ( 210 ). the actuation of the push rod ( 140 ) is shown in fig3 a - 3b . in particular , fig3 a illustrates the cannula ( 130 ) located within the working channel ( 110 ) of the biopsy device . according to the exemplary embodiment shown in fig3 a , as the push rod ( 140 ) is urged through the distal end of the cannula ( 130 ), the expandable member ( 200 ) contacts a wall ( 216 ) at the distal end of the working channel ( 110 ) adjacent aperture ( 120 ). as the push rod ( 140 ) is further advanced , the expandable member ( 200 ) acts against wall ( 216 ) and the internal surface of working channel ( 110 ) so to expand to fill the working channel ( 110 ). as the push rod ( 140 ) is urged further toward the distal end of the working channel ( 110 ), the expandable member ( 200 ) expands through with the aperture ( 120 ; best seen in fig3 a ) in the working channel ( 110 ). the expandable member ( 200 ) is expanded , thereby substantially filling the aperture ( 120 ). for example , according to one exemplary embodiment , the expandable member ( 200 ) is made of a resilient material that is compressed while in the cannula ( 131 ) and the working channel ( 110 ). such materials may include , without limitation , nitinol , an expandable mesh material , and / or shape memory material . according to other exemplary embodiments , the material may be substantially uncompressed or slightly compressed while in the cannula ( 131 ) and / or the working channel ( 110 ). when the push rod ( 140 ) is advanced sufficiently the expandable member ( 200 ) comes into contact with the wall ( 216 ) at the distal end of the working channel ( 110 ). advancing the push rod ( 140 ) compresses the expandable member ( 200 ) about its length within the working channel ( 110 ). this compression causes the expandable member ( 200 ) to expand in a direction perpendicular to the compression . this expansion causes the expandable member ( 200 ) to expand through the aperture ( 120 ). as the expandable member ( 200 ) expands in a perpendicular direction , it carries the marker ( 210 ) through the aperture ( 120 ) and into the surrounding biopsy cavity . according to the exemplary embodiment shown in fig3 b , the expandable member ( 200 ) may be expanded a predetermined amount to thereby deposit the marker ( 210 ) into the biopsy cavity . thereafter , the expansion of the expandable member ( 200 ) may be reduced slightly to provide spacing between the expandable member ( 200 ) and the deposited marker ( 210 ). the expandable member ( 200 ) remains sufficiently expanded to substantially fill the aperture ( 120 ), thereby sealing the aperture ( 120 ) and preventing the marker ( 210 ) from falling back into the deployment device ( 100 ). further , after deployment the working channel ( 110 ) may be rotated such that the opening ( 120 ) is rotated away from the deployed marker ( 210 ), thereby further preventing that the marker ( 210 ) does not fall back into the working channel ( 110 ). the deployment device ( 100 ) may then be withdrawn , such as by withdrawing the working channel ( 110 ) with the expandable member ( 200 ) expanded to maintain a seal about the aperture ( 120 ). thus , as the deployment device is removed , the aperture remains substantially sealed , thereby minimizing or reducing the possibility that the marker ( 210 ) will fall partially or completely into the working channel ( 110 ) and thus be dragged out . while the marker deployment device ( 100 ) has been described with reference to a working channel ( 110 ), those of skill in the art will appreciate that other configurations are possible . for example , according to one exemplary embodiment , the deployment device ( 100 ) may be introduced to the biopsy site by way of the tissue track created by a biopsy device in creating the biopsy site . other configurations are also possible , as will now be discussed in more detail . fig4 , 5 , and 6 illustrate a deployment device ( 400 ) that includes a cannula ( 410 ), a push rod ( 420 ), a protruding member ( 430 ), a receiving member ( 440 ), and a strip of flexible material ( 450 ). fig4 illustrates the deployment device ( 400 ) in isolation . fig5 illustrates the deployment device ( 400 ) at a first , pre - deployment position relative to a working channel ( 110 ). fig6 illustrates the deployment device ( 400 ) deploying a marker ( 210 ). as shown in fig4 , a seat ( 460 ) is defined in the push rod ( 420 ). a strip of flexible material , hereinafter referred to as a flexible strip ( 450 ), has a first position that is coupled to the receiving member ( 440 ). the receiving member is detachably coupled to a distal end of push rod ( 420 ). the flexible strip ( 450 ) extends from the receiving member ( 440 ), and along the surface of a seat ( 460 ). a second portion of flexible strip ( 450 ) is connected to a portion of push rod ( 420 ), adjacent seat ( 460 ), opposite receiving member ( 440 ). thus , while in the first position , the marker ( 210 ), which is positioned in the seat ( 460 ), rests on the flexible strip ( 450 ) while the marker ( 210 ) is received within the seat ( 460 ). further , as shown in fig4 , the distal end of the cannula ( 410 ) is substantially closed . additionally , a cannula aperture ( 470 ) is defined near the distal end of the cannula ( 410 ). according to the present exemplary embodiment , the protruding member ( 430 ) is disposed at or near the closed distal end of the cannula ( 410 ). the protruding member ( 430 ) is configured to be matingly coupled to the receiving member ( 440 ). in particular , as shown in fig5 , the cannula ( 410 ) may be advanced relative to the working channel ( 110 ) until the distal end of the cannula ( 410 ) comes into contact with the distal end of the working channel ( 110 ). at this position , the cannula aperture ( 470 ) is aligned relative to the aperture ( 120 ) defined in the working channel ( 110 ). thereafter , the push rod ( 420 ) may be advanced until the receiving member ( 440 ) comes into contact and engages with the protruding member ( 430 ). this contact couples the receiving member ( 440 ) to the protruding member ( 430 ). as the receiving member ( 440 ) is coupled to the protruding member ( 430 ), the seat ( 460 ) is aligned relative to the both the cannula aperture ( 470 ) and the aperture ( 120 ) defined in the working channel ( 110 ). thereafter , the push rod ( 420 ) may deploy the marker ( 210 ) while minimizing the possibility that the marker ( 210 ) will fall completely or partially back into the seat ( 460 ), the cannula aperture ( 470 ), and / or the aperture ( 120 ) defined in the working channel ( 110 ). such a configuration is shown in fig6 . in particular , as previously discussed , the protruding member ( 430 ) is coupled to the receiving member ( 440 ). as the push rod ( 420 ) is retracted , the protruding member ( 430 ) retains the receiving member ( 440 ) in contact therewith . as the push rod ( 420 ) is retracted , the first portion of flexible strip ( 450 ) is retained in contact with the receiving member ( 440 ) and the second portion of flexible strip ( 450 ) is retained to a portion of the push rod ( 420 ). consequently , as the distal end of the push rod ( 420 ) is retracted while the flexible strip ( 450 ) remains stationary , a center portion of flexible strip ( 450 ) that is positioned over seat ( 460 ) extends upwardly , carrying marker ( 210 ) through aperture ( 470 ). as the center portion of flexible strip ( 450 ) is driven upward and out of the seat ( 460 ), the marker ( 210 ) is also upwardly displaced . as introduced , when the distal end of the cannula ( 410 ) is in contact with the distal end of the working channel ( 110 ), the cannula aperture ( 470 ) and the aperture ( 120 ) in the working channel ( 110 ) are aligned . as the marker ( 210 ) is driven upward , it is urged through the cannula aperture ( 470 ), through the aperture ( 120 ) in the working channel ( 110 ), and then deposited into the biopsy site . as the marker ( 210 ) is deposited into the biopsy site , the flexible strip ( 450 ) closes the cannula aperture ( 470 ) and minimizes the space between the aperture ( 120 ) in the working channel ( 110 ) and the cannula ( 410 ). thus , as the deployment device ( 400 ) and the working channel ( 110 ) are removed , the flexible strip ( 450 ) minimizes the possibility that the marker ( 210 ) will fall partially or completely back into the working channel ( 110 ) or cannula ( 410 ). while a working channel of a biopsy device has been described in introducing the deployment device to a biopsy site , those of skill in the art will appreciate that the deployment device ( 400 ) may be introduced in other ways , such as by the tract formed by the biopsy device when performing the biopsy . fig7 and 8 illustrate a deployment device ( 700 ) that includes a cannula ( 710 ), a push rod ( 720 ), a platform ( 730 ), and at least one biasing member , such as springs ( 740 ). in particular , fig7 illustrates the deployment device ( 700 ) in isolation while in a first , pre - deployment position . as seen in fig7 , the cannula ( 710 ) has a cannula aperture ( 750 ) defined therein . while in the first position , the push rod ( 720 ) is positioned behind the cannula aperture ( 750 ). in this position , the marker ( 210 ) is carried by the platform ( 730 ). in this position , the springs ( 740 ) associated with the platform ( 730 ) are retained in a compressed position within the cannula ( 710 ) with ends ( 755 , 760 ) of platform ( 730 ) being functionally retained by shoulders ( 770 , 780 ). the push rod ( 720 ) is advanced to actuate the deployment device , as shown in fig8 . as shown in fig8 , the deployment device ( 700 ) may be introduced to a biopsy site with a working channel ( 110 ). more specifically , according to one exemplary embodiment , the cannula ( 710 ) is advanced relative to the working channel ( 110 ) until the distal end of the cannula ( 710 ) comes into contact with the distal end of the working channel ( 110 ). as the cannula ( 710 ) is thus advanced , the push rod ( 720 ) is maintained in the first position described above . further , as the cannula ( 710 ) comes into contact with the distal end of the working channel ( 110 ), the cannula aperture ( 750 ) is aligned relative to the aperture ( 120 ) defined in the working channel ( 110 ). thereafter , the push rod ( 720 ) may be advanced relative to the cannula ( 710 ). for example , the push rod ( 720 ) may be advanced until a distal end ( 790 ) of the push rod ( 720 ) contacts an inner wall ( 795 ) of cannula ( 710 ). in one embodiment , the contact between the inner wall ( 795 ) and the distal end ( 790 ) of push rod ( 720 ) causes the shoulders ( 770 , 780 ) to flex , thereby releasing the platform ( 730 ). in another embodiment , one of the shoulders ( 780 ) is constructed of a compressible material . as the push rod ( 720 ) is advanced relative to the cannula ( 710 ), the compressible shoulder ( 780 ) contacts an abutment that extends downwardly into the cannula ( 710 ) adjacent the cannula aperture ( 750 ) such that the compressible shoulder ( 780 ) compresses , thereby releasing the platform ( 730 ). once the platform ( 730 ) is released , the biasing elements ( 740 ) push the platform ( 730 ) and the marker ( 210 ) carried therein upwardly , thereby deploying the marker ( 210 ) into the biopsy cavity . more specifically , as previously introduced , while in the body of the cannula ( 710 ), the platform ( 730 ) is retained in a compressed position . as the platform ( 730 ) is moved into communication with the cannula aperture ( 750 ), the biasing elements ( 740 ) release the platform ( 730 ) from the cannula ( 710 ). according to one exemplary embodiment , the platform ( 730 ) and the cannula aperture ( 750 ) are slightly larger than the aperture ( 120 ) defined in the working channel ( 110 ). thus , as the platform ( 730 ) is released , it is urged outward until it comes into contact with the working channel ( 110 ). thus , the platform ( 730 ) obstructs the aperture ( 120 ). as the platform ( 730 ) is thus urged outwardly , the marker ( 210 ) is pushed through the aperture ( 120 ) and is thus deposited in the biopsy site . the deployment device ( 700 ) may then be removed . the deployment device ( 700 ) and working channel ( 110 ) may be removed while the platform ( 730 ) remains in position to obstruct the aperture ( 120 ). thus , the deployment device ( 700 ) is configured to deposit the marker ( 210 ) while minimizing the possibility that the marker ( 210 ) will fall partially or completely into the working channel ( 110 ) and / or the deployment device ( 700 ). accordingly , the deployment device ( 700 ) minimizes the possibility of drag out . while a working channel has been described for introducing the deployment device to the biopsy site , those of skill in the art will appreciate that the deployment device ( 700 ) may be introduced by any suitable means , such as through the tract cut by a biopsy device in creating the biopsy site . fig9 , 10 , and 11 illustrate a deployment device ( 900 ) that includes a selectively opening outlet ( 905 ) according to one exemplary embodiment . an exemplary embodiment will be discussed that includes a cannula ( 910 ) with the selectively opening outlet ( 905 ) coupled thereto . a push rod ( 930 ) is received within the cannula ( 910 ). as will be discussed in more detail below , the selectively opening outlet ( 905 ) allows the marker ( 210 ) to be selectively deployed in a biopsy site while minimizing the possibility that the marker will be dragged out as the deployment device ( 900 ) is removed . fig9 illustrates the deployment device ( 900 ) in a first , pre - deployment position within a working channel ( 110 ). as shown in fig9 , the push rod ( 930 ) is sized to translate within the cannula ( 910 ). a ramp ( 940 ) or other inclined surface is formed in the distal end of the inner cannula ( 910 ). in the preliminary position , the marker ( 210 ) is located in a marker staging cavity ( 920 ) defined in the space between the distal end of the cannula ( 910 ) and the distal end of the push rod ( 930 ). in the first position , the selectively opening outlet ( 905 ), and the aperture ( 120 ) defined in the working channel ( 110 ) are aligned . the push rod ( 930 ) is actuated to selectively open the selectively opening outlet ( 905 ) and deposit the marker ( 210 ) in a biopsy site . in particular , fig1 illustrates the push rod ( 930 ) being advanced toward the ramp ( 940 ). the push rod ( 930 ) may be flexible or rigid . alternatively , the push rod ( 930 ) may be formed with a flexible material , but also includes a stiffening sleeve therein . further , the push rod may be formed of any suitable material . suitable materials include , without limitation , plastic and metallic materials . as the push rod ( 930 ) is thus advanced , the distal end of the push rod ( 930 ) contacts the marker ( 210 ) thereby urging the marker ( 210 ) toward the ramp ( 940 ). as the marker ( 210 ) engages the ramp ( 940 ), an end of the marker ( 210 ) is urged into contact with the selectively opening outlet ( 905 ). according to one exemplary embodiment , the selectively opening outlet ( 905 ) is biased to remain in a closed position . for example , the cannula ( 910 ) and selectively opening outlet ( 905 ) may be formed of a resilient material , such as a plastic material . accordingly , the selectively opening outlet ( 905 ) may be biased to remain in a closed position . after the marker ( 210 ) is moved into contact with the selectively opening outlet ( 905 ), continued advancement of the push rod ( 930 ) drives the marker ( 210 ) further up the ramp ( 940 ). in one embodiment , the push rod ( 930 ), which may have at least a distal end portion that has a predetermined degree of flexibility is advanced such that the distal end of the push rod is advanced through the selectively opening outlet ( 905 ) to insure that the marker ( 210 ) fully exits the deployment device ( 900 ). as illustrated in fig1 a , the pushrod ( 930 ) is advanced and bends at the interface of ramp ( 940 ) in a flexion region ( 950 ). the marker ( 210 ) moves further up the ramp ( 940 ) and the marker ( 210 ) deflects the selectively opening outlet ( 905 ) outwardly . thus , the bias which maintains the selectively opening outlet ( 905 ) closed is overcome and the selectively opening outlet ( 905 ) is opened . as illustrated in fig1 b , the push rod ( 930 ) is further advanced until the marker ( 210 ) continues through the selectively opening outlet ( 905 ) through the aperture ( 120 ) defined in the working channel ( 110 ), and into the biopsy site . fig1 c illustrates the deployment device in a final stage of deploying the marker . as introduced , the selectively opening outlet ( 905 ) is biased to stay in a closed position . thus , as the marker ( 210 ) clears the selectively opening outlet ( 905 ), the selectively opening outlet ( 905 ) returns to a closed position relative to the cannula ( 910 ). accordingly , after the marker ( 210 ) has been deposited , the selectively opening outlet ( 905 ) closes , thereby closing off the cannula ( 910 ) while minimizing any space between the cannula ( 910 ) and the working channel ( 110 ). once the marker ( 210 ) has been deposited , the deployment device ( 900 ) and working channel ( 110 ) may be removed without the marker ( 210 ) being dragged out . further , selectively opening outlet ( 905 ) closes behind marker ( 210 ) and prevents marker ( 210 ) from following push rod ( 930 ) back within working channel ( 110 ). as can be seen with fig9 - 11c , the cross section of push rod ( 930 ) is smaller than marker ( 210 ). the difference in size provides for the selectively opening outlet ( 905 ) to “ wipe off ” marker ( 210 ) from the distal end of push rod ( 930 ). this “ wiping off ” action occurs because the bias of selectively opening outlet ( 905 ) follows the smaller cross section of push rod ( 930 ) and allows the selectively opening outlet ( 905 ) to begin closing behind marker ( 210 ). while a working channel has been described for introducing the deployment device to the biopsy site , those of skill in the art will appreciate that the deployment device ( 900 ) may be introduced by any suitable means , such as through the tract cut by a biopsy device when creating the biopsy site . fig1 - 15 illustrate a deployment device ( 1200 ) that includes a flexible strip ( 1210 ) having a first end secured to an internal wall ( 1212 ) of a distal end of a cannula ( 1220 ). fig1 a illustrates the components of the deployment device ( 1200 ) in a first , pre - deployment position . as shown in fig1 a , the deployment device ( 1200 ) also includes a push rod ( 1230 ). in the first position , the push rod ( 1230 ) has a distal end ( 1232 ) that extends over a portion of a proximal end ( 1234 ) of the flexible strip ( 1210 ) thereby depressing a portion of the flexible strip ( 1210 ). the cannula ( 1220 ), according to the present exemplary embodiment , has a cannula aperture ( 1240 ) defined therein . the cannula aperture ( 1240 ) is adjacent the distal end of the cannula ( 1220 ). the distal end of flexible strip ( 1210 ) is secured to the internal wall ( 1212 ) at the distal end of the cannula ( 1220 ) and aligned with the proximal and distal edge of aperture ( 1240 ). in the first position , the flexible strip ( 1210 ) extends away from the distal end of the cannula ( 1220 ) past the cannula aperture ( 1240 ) and beyond the distal end ( 1232 ) of the push rod ( 1230 ). the flexible strip ( 1210 ) is preliminarily and selectively retained in this position by the push rod ( 1230 ). more specifically , fig1 b illustrates a cross sectional view taken along section 12 b - 12 b as shown in fig1 b , in the first position , the proximal end of the flexible strip ( 1210 ) is retained between the distal end ( 1232 ) of the push rod ( 1230 ) and an interior wall of the cannula ( 1220 ). with the flexible strip ( 1210 ) thus retained , the flexible strip ( 1210 ) defines a retaining cavity ( 1250 ) that extends into a flexible ramp . in this position , the marker ( 210 ) rests on the flexible strip ( 1210 ) within the retaining cavity ( 1250 ) near the distal end ( 1232 ) of the push rod ( 1230 ). the deployment device ( 1200 ), according to the present exemplary embodiment , is actuated by advancing the push rod ( 1230 ). as the push rod ( 1230 ) is advanced , the distal end ( 1232 ) of the push rod ( 1230 ) comes into contact with the marker ( 210 ). as a result , when the push rod ( 1230 ) is advanced , the marker ( 210 ) is also advanced . in particular , as shown in fig1 , as the marker ( 210 ) is advanced , it is driven along the flexible strip ( 1210 ), thereby reducing the size of the retaining cavity ( 1250 ). more specifically , the marker ( 210 ) is advanced along the flexible strip ( 1210 ) and up the flexible ramp such that the push rod ( 1230 ) captures an increased length of the flexible strip ( 1210 ). the push rod ( 1230 ) is advanced until the marker ( 210 ) is driven through the cannula aperture ( 1240 ) such that the marker ( 210 ) is deployed in the biopsy site . once the marker ( 210 ) is deployed , the push rod ( 1230 ) may be withdrawn until the push rod ( 1230 ) is behind the flexible strip ( 1210 ) and no longer retaining the proximal end ( 1234 ) of the flexible strip ( 1210 ). as previously discussed , while in the preliminary position and while the marker ( 210 ) is being deployed , the push rod ( 1230 ) depresses the flexible strip ( 1210 ). according to such an exemplary embodiment , the flexible strip ( 1210 ) is formed of a resilient material that is configured to spring back to a shape when not depressed by the push rod ( 1230 ). thus , the push rod ( 1230 ) may temporarily retain the flexible strip ( 1210 ) until it is no longer in contact with the flexible strip ( 1210 ). thereafter , the flexible strip ( 1210 ) will automatically return to its un - depressed state when the push rod is removed , as shown in fig1 . according to the present exemplary embodiment , as the flexible strip ( 1210 ) returns to its un - depressed state , it obstructs the cannula aperture ( 1240 ). with the cannula aperture ( 1240 ) thus obstructed , the flexible strip ( 1210 ) minimizes the possibility that the marker ( 210 ) may fall partially or completely back into the deployment device ( 1200 ). as seen in fig1 a and 15b , the push rod ( 1230 ) may be advanced slightly after the flexible strip ( 1210 ) is released from its depressed state to thereby securely close the cannula aperture ( 1240 ). as seen in fig1 a , as the push rod ( 1230 ) is again advanced , the push rod ( 1230 ) secures the flexible strip ( 1210 ) to the cannula ( 1220 ). more specifically , the push rod ( 1230 ) maintains the proximal end ( 1234 ) of the flexible strip ( 1210 ) on the side of the cannula aperture ( 1240 ). thus , as seen in fig1 b , the flexible strip ( 1210 ) is located between the push rod ( 1230 ) and the cannula ( 1220 ) on the side of the cannula aperture ( 1240 ), thereby securely closing the cannula aperture ( 1240 ). the deployment device ( 1200 ) may thus be withdrawn while minimizing the possibility that the marker ( 210 ) will fall partially or completely into the deployment device ( 1200 ), and thus be dragged out . fig1 illustrates a deployment device ( 1600 ) according to one exemplary embodiment . as shown in fig1 , the deployment device ( 1600 ) includes an arm ( 1610 ) that is pivotally connected to an internal surface of a cannula ( 1620 ). one or more biasing elements ( 1650 ), such as a spring , are secured to the arm ( 1610 ) to move the arm ( 1610 ) from a pre - deployment position to a deployment position ( shown in phantom ). a marker ( 210 ) is positioned on a surface of the arm ( 1610 ). the cannula ( 1620 ) further has a cannula aperture defined therein ( 1630 ), where the aperture ( 1630 ) is positioned over the arm ( 1610 ). the deployment device ( 1600 ) may be introduced through the working channel ( 110 ) of a biopsy device . the deployment device ( 1600 ) further includes a selectively retractable cover ( 1640 ). when the deployment device ( 1600 ) is in a first , pre - deployment position , the cover ( 1640 ) is positioned over the arm ( 1610 ) that is carrying the marker ( 210 ). a slot ( 1642 ) is formed on a bottom portion of cover ( 1640 ) to permit cover ( 1640 ) to pass over the arm ( 1610 ). when the sleeve extends over the arm ( 1610 ), arm ( 1610 ) is held down such that the marker ( 210 ) is retained within the deployment device ( 1600 ). however , the cover ( 1640 ) may be selectively retracted , such that the biasing element ( 1650 ) pivots the arm ( 1610 ) upwardly , protruding the marker ( 210 ) out of the aperture ( 1630 ). once deployed , the cover ( 1640 ) may be slid back over the arm ( 1610 ) and extends past the aperture ( 1630 ) to the distal end of cannula ( 1620 ). thus , the cover ( 1640 ) dislodges the marker ( 210 ) from the arm ( 1610 ) and obstructs the aperture ( 1630 ) thereby preventing the marker ( 210 ) from re - entering the deployment device ( 1600 ). in another embodiment , deployment device ( 1600 ) may be used with a cannula within a cannula system ( e . g ., a cutting instrument ). fig1 further illustrates the cannula with a cannula system wherein the cover ( 1640 ) is embodied as the inner cutting instrument element . the distal end of cover ( 1640 ) may then be used to hold down the arm ( 1610 ). the preceding description has been presented only to illustrate and describe exemplary embodiments . it is not intended to be exhaustive or to limit the disclosure to any precise form disclosed . many modifications and variations are possible in light of the above teaching . it is intended that the scope of the disclosure be defined by the following claims .
a biopsy marker deployment device adapted to selectively deposit a marker in a target location , such as a biopsy site . in one embodiment , the device includes a deployment assembly comprising a cannula adapted to house at least one marker , an outlet aperture defined by a portion of the cannula , and an actuatable pushrod slidably disposed and movable within the cannula . the deployment assembly further comprises a selectively opening outlet door movable between an open position and a closed position . the outlet door is biased in the closed position and at least partially obstructs the aperture in the closed position to prevent a marker from reentering the cannula upon deployment .