fig1 illustrates a retrieval system 10 suitable for use in removing foreign objects such as embolic coils and stents . retrieval system 10 includes a catheter 20 formed of a polymeric material as is known in the art , having distal end 22 , proximal end 24 and lumen 25 extending therethrough . catheter hub 26 , having a luer connector is coupled to proximal end 24 . while not shown , the construction of catheter 20 may utilize known catheter technologies that incorporate braiding and or coiling using metallic or non - metallic reinforcing filamentous materials to provide high strength while maintaining catheter flexibility . the incorporation of lubricious hydrophilic and or hydrophobic materials on the inner and or outer surface of the catheter is considered to be within the scope of known catheter construction techniques and suitable for use in a retrieval system according to embodiments of the present invention . positioned within catheter 20 is an elongate flexible retrieval device 30 having distal end 32 and proximal end 34 . retrieval device 30 includes a pushable flexible member 36 extending from proximal end 34 to distal end 32 . flexible member 36 preferably takes the form of a core wire having a distal taper similar to that of guidewires . suitable materials include stainless steels , nitinol and polymers . preferably a flexible coil 38 is positioned over the distal portion of flexible member 36 to aid in delivery . capture member 40 is coupled to coil 38 at distal end 32 typically through soldering , welding or gluing . fig2 provides an enlarged view of the distal end of retrieval system 10 where capture member 40 is shown to include capture arms 42 and 44 that extend outwardly from the longitudinal axis of retrieval device 30 . capture arms 42 and 44 are formed of a resilient material and biased in an open configuration . capture member 40 may be formed from a tube of nitinol that has been partially split wherein each half of the split tube is shaped to become capture arms 42 and 44 . capture arms 42 and 44 have distal portions 46 and 48 as well as proximal portions 50 and 52 respectively . the distal portions of the capture arms include a plurality of engagement elements represented by engagement elements 54 and 56 on capture arm 42 and engagement elements 58 and 60 on capture arm 44 . engagement elements 54 , 56 , 58 and 60 extending from capture arms 42 and 44 are spaced apart and preferably oriented perpendicular to the longitudinal axis of flexible member 36 . the orientation of the engagement elements relative to the capture arms is depicted in the perspective view of fig3 . as shown in fig3 , arms 42 and 44 are generally spaced apart when capture member 40 is in an unconstrained configuration . the distance between arms 42 and 44 may range from 1 . 5 mm to 5 mm for devices designed for use in neurovascular applications , however , may range from 1 . 5 mm to 50 mm for devices designed for use in other body lumens . the lengths of arms 42 and 44 are also dependant upon a particular design for a particular application but typically range from 3 mm to 50 mm . representative engagement elements 54 and 56 are spaced apart on the same side of capture arm 42 as previously discussed . the length and spacing distance for engagement elements is dependant upon the designed device and dimensions of the object to be removed but may typically range from length of 0 . 3 mm to 10 mm and a spacing distance of 0 . 010 inches to 0 . 080 inches . capture member 40 of retrieval device 30 is operable between an unconstrained configuration in which arms 42 and 44 are open and a constrained configuration , such as within a catheter lumen , where the arms are generally closed or collapsed . in the constrained configuration , arms 42 and 44 are brought together such that engagement elements 52 , 54 56 and 58 intermesh . preferably , the retrieval device comprises a biocompatible resilient material . suitable resilient materials include metal alloys such as nitinol , titanium , stainless steel . additional suitable materials include polymers such as polyimides , polyamides , fluoropolymers , polyetheretherketone ( peek ) and shape memory polymers . these materials may be formed into desired shapes by a variety of methods which are appropriate to the materials be in utilized such as laser cutting , thermal heat treating , vacuum deposition , electro - deposition , vapor deposition , chemical etching , photo etching , electro etching , stamping , injection molding , casting or any combination thereof . in addition , the biased resiliency of these materials allow a retrieval device with a normally expanded configuration to have a collapsed , small diameter configuration when constrained within a delivery catheter suitable for delivery to a target site and upon being deployed at a target site return to its expanded configuration . a method of removing a foreign object such as an embolic coil using retrieval system 10 is illustrated in fig4 , 5 , 6 and 7 . catheter 20 is introduced into vessel 200 and distal end 22 is positioned adjacent a target site such as embolic coil 202 . retrieval device 30 is then introduced into and advanced through the catheter with the arms 42 and 44 in a constrained collapsed configuration as illustrated in fig4 . as shown in fig5 , when capture member 40 exits the lumen of catheter 20 , arms 42 and 44 move to an open unconstrained configuration . the capture member is then manipulated to cause the engagement elements of capture arms 42 and 44 to sufficiently engage a portion of embolic coil 202 . catheter 20 is then advanced relative to retrieval device 30 such that distal end 22 causes arms 42 and 44 to collapse , thereby securing a portion of coil 202 as illustrated in fig6 . fig7 depicts retrieval system 10 , along with secured coil 202 , being retracted from the target site and subsequently removed from the body . novel devices , systems and methods have been disclosed to remove foreign objects from a body lumen of a mammal . although preferred embodiments of the invention have been described , it should be understood that various modifications including the substitution of elements or components which perform substantially the same function in the same way to achieve substantially the same result may be made by those skilled in the art without departing from the scope of the claims which follow .