referring now to the drawings and the characters of reference marked thereon , fig1 illustrates a preferred embodiment of the detachable cryosurgical probe of the present invention , designated generally as 10 . the detachable cryosurgical probe 10 includes a disposable probe assembly , designated generally as 12 and a reusable probe assembly , designated generally as 14 . the reusable probe assembly 14 includes a fluid supply line 16 that is connected at an inlet section 18 to a source ( not shown ) of cryogenic fluid . the fluid source may be , for example , a cryosurgical system such as that manufactured by present assignee , endocare , inc ., irvine , calif . such a cryosurgical system typically utilizes argon gas from an argon gas source to provide joule - thomson cooling of the cryosurgical probes . alternatively , nitrogen can be used . alternatively , a fluid supply system can be utilized that does not require an external fluid supply source . heating of the cryosurgical probes is typically provided by a helium gas source for providing a helium gas flow through the joule - thomson nozzle of the cryosurgical probe . this provides a heating effect . such heating of the cryosurgical probes is provided to unstick the probes from the treated tissue for cryoprobe removal . a gas delivery assembly of the disposable probe assembly 12 includes a shaft 20 that has a freezing zone . spaced markings 21 may be provided on the outer surface of the cryosurgical probe 10 . these markings 21 may be , for example , at 1 cm intervals . fig2 shows the disposable probe assembly 12 detached from the reusable probe assembly 14 , as will be described in detail below . referring now to fig3 , the disposable probe assembly 12 is shown attached to the reusable probe assembly 14 . this figure is broken away in a few places for the purposes of clarity . the disposable probe assembly 12 includes a gas delivery assembly 22 , a finger lock assembly including finger lock element 24 , and a disposable handle assembly 26 . the gas delivery assembly 22 includes a stem 28 and a fluid conduit subassembly 30 bonded to the stem 28 . the fluid conduit subassembly 30 is for delivering and returning cooling fluid used for cryogenic cooling . the finger lock element 24 includes a distal finger lock element section 32 ( see also fig6 ) having a threaded inner surface for engagement with a threaded outer surface of the stem 28 . four radially spaced fingers 34 ( see also fig7 ) extend proximally from the distal finger lock element section 32 . each finger 34 has a ramped surface 36 for operatively engaging an associated ramp section on the stem 28 during use ; and , a female lip 38 at a proximal end thereof . the disposable handle assembly 26 includes a proximal handle section 40 , a distal handle section 42 ; and , a breakaway collar 44 . the proximal handle section 40 has a distal end having an inner surface that is operatively engaged with an outer surface of the finger lock element 24 ( this region of engagement designated 46 ) so as to resist relative rotation and axial motion therebetween . as can be seen in fig6 , hex shaped surfaces are utilized to prevent relative rotation ; however , obviously other geometric shapes and other means can be used to prevent such rotation such as radial bumps , pins , etc . the distal handle section 42 of the disposable handle assembly 26 has an inner surface that is operatively engaged with another outer surface of the stem 28 ( this region of engagement designated 48 ) so as to resist relative rotation and axial motion therebetween . again , this region of engagement may be hex shaped . the breakaway collar 44 is positioned between the proximal handle section 40 and the distal handle section 42 . the fluid conduit subassembly 30 includes a joule - thomson ( j - t ) tube 50 bonded to the stem 28 . it may be welded thereto , as shown by numeral designation 52 . the j - t tube 50 receives the cooling fluid from the reusable probe assembly 14 . the distal end of the j - t tube 50 comprises a j - t nozzle 54 . a safety washer 56 is positioned within a front end of an elongated central opening 58 of the distal handle section 42 of the disposable handle assembly 26 . a shaft 60 of the fluid conduit subassembly 30 is secured to the safety washer 56 within an opening of the safety washer 56 and within the elongated central opening 58 . the shaft 60 extends beyond the distal handle section 42 to provide a cooling surface for cryogenic cooling . in this embodiment a vacuum tube 62 is integrally connected with an inner surface of the shaft 60 . ( as will be disclosed below in another embodiment there may alternatively be a slideable connection .) a high pressure seal comprising a high pressure o - ring 62 is positioned about a proximal end section of the stem 28 for sealing cooperation ( as shown by numeral designation 64 in fig5 ) with an inner surface of a manifold assembly 66 of the reusable probe assembly 14 . the vacuum tube 62 has a desired insulative air gap formed therein . the air gap provides selected non - cooling areas of the cryosurgical probe . referring now to fig4 , the reusable probe assembly 14 includes the manifold assembly 66 and a reusable handle assembly 68 secured about the periphery of the manifold assembly 66 . the reusable handle assembly 68 includes a first end portion 67 and a second end portion 69 . the manifold assembly 66 includes an outer covering 71 . the reusable probe assembly preferably includes a safety valve assembly , designated generally as 70 , operatively engaged with the manifold assembly 66 for impeding cryogenic working fluid flow when the disposable probe assembly 12 is detached from the reusable probe assembly 14 . the safety valve assembly 70 includes a conical surface 72 formed in a proximal penultimate section 74 of a proximal end portion of the manifold assembly 66 . the manifold assembly 66 terminates , at its proximate end , with a proximal ultimate section 76 . the proximal ultimate section has a ball retaining cavity 78 formed therein . a ball 80 is positioned within the ball retaining cavity 78 . the function of this safety valve assembly 70 will be discussed below in detail . the reusable probe assembly also preferably includes an electrical confirmation assembly , designated generally as 82 , operatively engaged with the disposable probe assembly 12 for providing electrical confirmation that the disposable probe assembly 12 is connected . the electrical confirmation assembly 82 includes a slideable electrically conductive ring 84 positioned about an outer surface of the reusable probe assembly 14 and normally distally biased by a spring 86 . the electrical confirmation assembly 82 includes stationary electrically conductive lever spring contacts 88 and plastic housing 89 for the lever spring contact 88 . the lever spring contact 88 is electrically connected to the cryosurgical system by wires 85 . the function of this electrical confirmation assembly 82 will be discussed below in detail . in operation , when the disposable probe assembly is attached , as can be seen in fig5 , and 12 the breakaway collar 44 is an integral unit that prevents relative rotation between the proximal handle section 40 and the distal handle section 42 . in this configuration , the female lip 38 engages a male lip 90 of the manifold assembly 66 ; thereby securing the reusable probe assembly 12 to the disposable probe assembly 14 . referring now to fig9 and 13 , during an initial stage of detachment of the disposable probe assembly , the user rotates the distal handle section in a first direction relative to the proximal handle section to “ break away ” breakaway surfaces of the breakaway collar 44 , allowing the breakaway collar 44 to radially expand . in fig1 the breakaway collar 44 is shown removed ; however , during actual operation it may possibly dangle at that location . referring now to fig1 and 14 , during an intermediate stage of detachment of the disposable probe assembly 12 the user counter rotates the distal handle section 42 in an opposite second direction relative to the proximal handle section 40 . the relative rotation between the distal handle section 42 and the proximal handle section 40 provides axial movement of the distal handle section 42 toward the proximal handle section 40 via the engagement of the threaded inner surface of the distal finger lock element section 32 and the threaded outer surface of the stem 30 . the axial movement is enabled by the radial expansion of the breakaway collar 44 . the ramped surfaces 36 of the radially spaced fingers 34 engage the associated ramp section on the stem 30 during the axial movement thereby urging the fingers 34 to open . referring now to fig1 and 15 , during a final stage of detachment , the fingers 34 open sufficiently to allow disengagement of the male lip 90 from the female lip 38 , thus enabling the disposable probe assembly 14 to be detached from the reusable probe assembly 12 . as mentioned above , the safety valve assembly 70 , is operatively engaged with the manifold assembly 66 for impeding cryogenic working fluid flow when the disposable probe assembly 12 is detached from the reusable probe assembly 14 . as can be seen in fig1 , when the disposable probe assembly 12 is detached from the reusable probe assembly 14 and no cooling gas is flowing within manifold assembly 66 , the ball 80 is free to float freely within the ball retaining cavity 78 . however , when the disposable probe assembly 12 is detached from the reusable probe assembly 14 and cooling gas is flowing within the manifold assembly 66 ( as indicated by arrow 92 ), the ball 80 is urged into a volume defined by the conical surface 72 , thus providing sufficient sealing to prevent “ whipping ” of the disposable probe assembly 12 . as perhaps best seen in fig5 , when the disposable probe assembly 12 is connected to the reusable probe assembly 14 the joule - thomson ( j - t ) tube 50 bonded to the stem 28 maintains the ball 80 in a position away from the conical surface 72 , thus allowing the free flow of cooling gas 92 into the disposable probe assembly 12 . as mentioned above , and referring again to fig4 , an electrical confirmation assembly , designated generally as 82 , is operatively engaged with the disposable probe assembly 12 for providing electrical confirmation that the disposable probe assembly 12 is connected . when the disposable probe assembly 12 is not connected , the conductive ring 84 is not in contact with the lever spring contact 88 . when the disposable probe assembly 12 is connected , the conductive ring 84 is urged by the disposable probe assembly 12 in a proximal direction so that it contacts the lever spring contacts 88 providing a closed electrical circuit and electrical confirmation of the connection . a heat exchanger or cryostat 94 is utilized to provide heat exchange between inlet gas and outlet gas . although , as shown , the heat exchanger is preferably a coiled fin tube heat exchanger various other types of heat exchangers may be utilized such as a tube - in - tube sintered cryostat , threaded cryostat , coiled / sintered cryostat , or stacked coil cryostat . these different types of cryostats are disclosed and claimed in u . s . ser . no . 10 / 828 , 031 , entitled detachable cryosurgical probe , filed on apr . 20 , 2004 , incorporated herein by reference in its entirety . referring now to fig1 - 21 a second embodiment of the detachable cryosurgical probe system is illustrated , designated generally as 100 . in this system 100 the vacuum tube may be repositioned as desired relative to the shaft . this is accomplished by actuating a button assembly , designated generally as 102 , along a guideway 104 . fig1 and 17 show the vacuum tube in a first position ( i . e . labeled p 5 ). fig1 shows the vacuum tube moved to a second position ( i . e . labeled p 2 ). referring now to fig1 , the button assembly 102 can be seen in cross - section in the first position . a button 104 of the button assembly 102 is biased by a spring 106 . a slider assembly 108 is mechanically connected to the vacuum tube 110 and to the button assembly 102 . thus , the shaft 112 and the vacuum tube 110 are capable of moving relative to each other . the button assembly 102 can be locked into position to prevent unintentional movement . a safety washer assembly 114 is securely connected to the shaft 112 . it includes an o - ring 116 for sealing the shaft 112 and the vacuum tube 110 . another o - ring 118 at the front of the stem 120 seals the vacuum tube 110 and stem 120 . referring now to fig2 , the vacuum tube 110 is shown having been moved toward a second position relative to the shaft 112 by the actuation of button assembly 102 . referring now to fig2 , the button assembly 102 is shown moved to position p 4 . thus , the size and shape of the generated iceball can be varied in accordance with a specific desired need . during operation , with the disposable probe assembly 12 attached to the reusable probe assembly 14 , cryogenic fluid originating from ( typically ) an argon tank flows through the supply line 16 within the cryostat 94 and through the manifold assembly as shown by arrow 92 ( in , for example , fig5 ). the flow is directed through the safety valve assembly 70 and then through the central passageway in the high pressure stem 28 via j - t tube 50 , and out of the j - t port 54 ( see fig3 ). after being expelled from the j - t port 54 the return fluid is directed in the space between the inner surface of the vacuum tube 62 and the outer surface of the j - t tube 50 . it then flows through openings in the manifold assembly 66 , as indicated by arrow 114 ( fig5 ) and adjacent to the heat exchanger 94 . the return fluid is eventually expelled via the hose 16 . in the device illustrated the cryosurgical probe is shown with a pointed tip to provide insertion into the patient &# 39 ; s tissue for the desired application . however , it is understood that the tip may be blunt , depending on the application . for example , for certain applications direct insertion is desirable . for other applications , insertion via a cannula / introducer is preferred . although application of this device utilizing ct guidance is preferred , the cryosurgical probe 10 may be used with a variety of guidance tools , such as mri and ultrasound . in one preferred implementation ultrasound is used for initial guidance , followed up with ct for final confirmation . although the present invention has been discussed above with respect to a cryosurgical probe having a rigid outer sheath , the cryosurgical probe may be made to be malleable by including at least one malleable segment thereon . malleable segments are formed of material that permit reshaping and bending to reposition the ablating surface for greater ablation precision . an example of a cryosurgical probe having malleable characteristics is disclosed and claimed in our co - pending patent application ser . no . 09 / 957 , 337 , pub . no . us 2003 / 0055415 a1 , filed on sep . 20 , 2001 entitled malleable cryosurgical probe , incorporated in its entirety herein by reference . one method for providing malleable characteristics includes providing a malleable shaft with a bellows portion . u . s . pat . no . 6 , 767 , 346 , filed jul . 27 , 2002 entitled cryosurgical probe with bellows shaft , incorporated in its entirety herein by reference , discloses use of a bellows portion for providing the necessary reshaping and bending . if the detachable cryosurgical probe is utlilized in combination with ultrasound the outer sheath may have an echogenic coating with , for example , a porous microstructure having the ability to trap microscopic air bubbles . this creates thousands of highly efficient ultrasound reflectors on the surface of the sheath . thus , while the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed , they are merely illustrative of the principles of the invention . for example , even though the finger lock element has been described specifically with respect to the present cryosurgical probe it is understood that it can be used on other types of cryosurgical probes that , for example , may not be single use . further , the finger lock element may be used for many applications which require a quick disconnect ( both single use and multiple use ). these may include , for example , control valves for water heaters , pneumatic systems for controls that require quick disconnects , electrical connectors , etc . although the cryostat 94 has been shown positioned within the manifold assembly 66 it may be positioned in other locations , notably , for example , in the hose 16 or within the fluid source . although the cryosurgical probe system is particularly advantageous for prostate cryosurgery it is also advantageous for many other types of ablation applications , such as radiological applications . other embodiments and configurations may be devised without departing from the spirit of the invention and the scope of the appended claims .
the detachable cryosurgical probe includes a disposable probe assembly and a reusable probe assembly . the disposable probe assembly includes a breakaway collar which , when twisted away , activates a finger lock element which provides release of the disposable probe assembly from the reusable probe assembly . additional features include a safety valve assembly for impeding cryogenic working fluid flow when the disposable probe assembly is detached from the reusable probe assembly and an electrical confirmation assembly for providing electrical confirmation that the disposable probe assembly is connected . other embodiments include a sliding mechanism that allows for selectively positioning of the vacuum tube relative to the shaft to create an ice ball of the desired size and configuration .