Injector providing drive member advancement and engagement with syringe plunger, and method of connecting a syringe to an injector

An injector for injecting a fluid from a syringe (which syringe includes a body, a plunger moveably positioned within the body, and an encoding device providing syringe information)r includes a housing, a motor disposed within the housing, a controller operably associated with the motor, a sensor operably associated with the controller and operable to read the encoded syringe information provided by the encoding device when the syringe is attached to the injector, a drive member disposed in the housing and powered by the motor, the drive member operable to automatically advance and engage the plunger when the sensor reads the syringe information provided by the encoding device, and a plunger engagement detection device operably associated with the controller and operable to indicate when the drive member of the injector has engaged the plunger of the syringe.

FIELD OF THE INVENTION

The present invention relates to injectors and injector systems, and, more particularly, to injectors and injector systems in which a syringe is connected to or loaded upon the injector in a powered or manual manner.

BACKGROUND OF THE INVENTION

A number of injector-actuated syringes and powered injectors for use in medical procedures such as angiography, computed tomography and NMR/MRI have been developed. For example, U.S. Pat. No. 4,006,736 discloses an apparatus for injecting fluid into the vascular system of a human being or an animal. Likewise, U.S. Pat. No. 4,677,980 discloses an angiographic injector and syringe wherein the drive member of the injector can be connected to, or disconnected from, the syringe plunger at any point along the travel path of the plunger via a releasable mechanism requiring rotation of the syringe plunger relative to the piston. Each of the injectors disclosed in U.S. Pat. Nos. 4,006,736 and 4,677,980 includes a pressure jacket that is breach or rear loaded with a syringe.

U.S. Pat. No. 5,300,031 discloses an injector system in which a syringe is loadable in and unloadable from a pressure jacket of an injector through an open front end in the pressure jacket. The injector system of U.S. Pat. No. 5,300,031 permits replacement of a syringe without retraction of the syringe plunger drive or disconnection of injection tubing connected to the syringe.

A front-loading syringe and injector system is disclosed in U.S. Pat. No. 5,383,858. The syringes disclosed in U.S. Pat. No. 5,383,858 can be readily and securely front-loaded directly and accurately on the injector or on a pressure jacket attached to the injector, thereby facilitating the loading-unloading operation as compared to prior systems. In the front-loading system of U.S. Pat. No. 5,383,858 and other currently available front loading systems, a user manually aligns the syringe in a desired orientation relative to the injector and manually inserts and locks the syringe in place.

In the system of U.S. Pat. No. 5,383,858, for example, an interlocking, releasable mechanism is activated and released upon proper axial and radial alignment and subsequent manual rotation of a rearward portion of a syringe relative to a front wall of the injector housing. In one embodiment, the releasable mechanism includes slots on the front wall of the housing for receiving retaining flanges on the rearward end of the syringe. The syringe is manually rotatable to engage the retaining flanges with associated or cooperating flanges on the injector mounting mechanism. The releasable mechanism also includes an annular sealing member on the injector housing front wall against which a resilient annular sealing member or flange on the syringe becomes seated as the syringe is positioned on the mounting mechanism. The resilient annular sealing member and the retaining flanges on the syringe receive the flanges on the injector mounting mechanism therebetween with an interference fit.

The syringe plunger of U.S. Pat. No. 5,383,858 must be appropriately axially and radially positioned relative to the drive member during loading of the syringe upon that injector system so that rotation of the syringe during loading will also cause engagement of the drive member and the syringe plunger.

Although front-loading syringes represent a significant advancement in the area of injector-actuated syringes and powered injectors for use therewith, the loading and unloading procedures therewith require significant operator time/involvement to ensure secure engagement. For example, the operator must ensure that the syringes of current front-loading systems are first properly aligned with and then securely connected to the injector and that the plunger is engaged by the injector drive member. These steps can require substantial time, dexterity and strength as a result of, for example, alignment requirements, awkward and complex motions and close design tolerances. In many cases the injector may also be positioned so that it is difficult for the operator to access the injector to load a syringe thereon. Moreover, injector heads are typically not securely anchored and can move during syringe loading, further complicating loading of a syringe thereon.

It is very desirable to develop new syringes, injectors, injector systems and methods to reduce operator time/involvement in loading the syringe onto the injector and/or in connecting the syringe plunger to the injector drive member, while ensuring secure engagement between the syringe (including the syringe plunger) and the injector.

SUMMARY OF THE INVENTION

The present invention provides improved injectors, injector systems, syringes and methods in which the syringe is loaded upon and/or unloaded from the injector in a powered or manual manner. The loading/connecting features of the present invention greatly simplify the process of loading a front-loading syringe onto an injector and frees valuable operator time to accomplish other tasks.

The powered loading features of the present invention also provide greater confidence of proper and secure engagement of the syringe to the injector and/or the syringe plunger to the injector drive member. Moreover, because the loading procedure is powered, tighter tolerances can be designed into the mounting and retaining mechanisms of the present invention than with previous front-loading systems in which tolerances were limited or loosened to facilitate manual loading. The tighter tolerances of the present invention substantially reduce or eliminate play or movement of the syringe after connection thereof to the injector, thereby facilitating more accurate control of the injector.

In one aspect, the present invention provides an injector for injecting a fluid from a syringe. The syringe includes an elongated body and a mounting member positioned on a rear portion of the body. The syringe further includes a plunger moveably positioned within the body of the syringe. The injector includes a housing having a front wall and a retainer on the front wall. The retainer is adapted to cooperate with the mounting member to retain the syringe on the front wall of the injector. Preferably, the syringe is releasably retained upon the front wall of the injector. The retainer includes a powered loader adapted to bring the mounting member and the retainer into secure engagement to securely connect the syringe to the injector. The injector further includes a powered drive member in the housing. The drive member is adapted to engage the plunger and control the movement of the plunger.

The mounting member of the syringe may be formed integrally with the remainder of the syringe in, for example, a polymer molding procedure. Alternatively, the mounting member may be formed separately from the syringe and attached thereto. For example, an adapter including the mounting member can be fabricated to be separate from and attachable to a syringe body. The adapter can, for example, be designed to accept a syringe such as disclosed in U.S. Pat. No. 5,383,858 to adapt that syringe or other syringes for use in the present invention. Preferably, the adapter is releasably connectible to the injector. The adapter is also preferably releasably connected or attached to the syringe.

Likewise, syringes for use in the present invention are readily adapted for use with other injectors through use of an adapter. Such an adapter can, for example, be used to load a syringe of the present invention on an injector as disclosed in U.S. Pat. No. 5,383,858.

In several embodiments, the powered loader of the present invention moves one or more components of the retainer to engage the mounting member and to bring the mounting member and the retainer into secure connection, thereby securely connecting the syringe to the injector. For example, the mounting member may include threading and the retainer may include a cooperating threaded member. The powered loader may rotate the threaded member of the retainer relative to the threading on the syringe to engage the threading on the syringe and securely connect the syringe to the injector.

In general, many types of cooperating attachment members can be used for the mounting member and the retainer. The mounting member may, for example, include a mounting flange or flanges (for example, a single annular flange or a plurality of flanges positioned about the circumference of a syringe or adapter) and the retainer may include a cooperating retaining flange or flanges. In this embodiment, the powered loader preferably moves the retainer to cause the retainer flange(s) to engage the mounting flange(s) to securely connect the syringe to the injector.

The injector may also include a loading or mounting sensor to determine when the syringe is in position for the powered loader to bring the mounting member and the retainer into secure engagement. The powered loading procedure can thereby be automatically initiated when the syringe is in position. The injector may also include one or more sensors to read information encoded upon the syringe. In another embodiment, a single sensor can be used to both read encoded syringe information and to initiate the powered loading process.

The syringe (or an adapter that is attached to the rear of the syringe as described above) may include a generally annular flange preferably positioned forward of the mounting flange(s) that forms a sealing engagement with a forward surface of the retainer to assist in creating a secure engagement of the syringe to the injector and to assist in preventing leakage of fluids into the injector.

Preferably, the drive member of the injector includes an engagement member on a forward end thereof. The engagement member is preferably adapted to connect or dock to the plunger upon forward advancement of the drive member. Preferably, the engagement member is suitable to connect to the plunger regardless of the axial position of the plunger within the syringe and regardless of the relative angular positions of the drive member and plunger about a generally common axis. Preferably, the drive member automatically connects to the plunger either during or shortly after the power loading or manual loading of the syringe onto the injector.

The drive member may, for example, be automatically advanced forward upon loading of the syringe on the injector to connect the drive member to the plunger. Whether the drive member is connected to the plunger automatically or by manual control, the injector preferably controls the motion of the drive member based upon syringe information encoded upon the syringe. For example, if the injector determines that the syringe is empty from the syringe information encoded upon the syringe, the injector preferably causes the drive member to advance the plunger forward to expel air from the syringe in preparation for loading the syringe with fluid. However, if the injector determines that the syringe is prefilled from the syringe information encoded upon the syringe, the injector preferably stops forward advancement of the drive member upon connection of the drive member with the plunger to prevent undesirable expelling of injection fluid. Controlling the drive member, for example, to perform certain preinjection procedures in a manner that depends upon the type of syringe loaded upon the injector can save valuable user time and helps standardize injection procedures.

In another aspect, the present invention provides a system for injecting a liquid medium that includes a front-loading syringe for injecting a fluid into a patient and a powered injector. The syringe preferably includes: an elongated body; a mounting member positioned on a rear portion of the body, and a plunger moveably positioned within the body of the syringe. The injector preferably includes: a housing having a front wall and a retainer on the front wall that is adapted to retain the syringe on the front wall. The retainer preferably includes a powered loader adapted to bring the mounting member and the retainer into secure engagement to securely connect the syringe to the injector. The injector further includes a powered drive member in the housing that is adapted to engage the plunger and control the movement of the plunger.

In a further aspect, the present invention provides a method of connecting a front-loading syringe to a powered injector including the steps of: positioning the syringe in a mounting position on the injector; and moving a retaining member of the injector in a powered manner to engage the syringe and connect the syringe to the injector.

In another aspect, the present invention provides a syringe for use with a powered injector including: an elongated body, a plunger moveably positioned within the body of the syringe, and a threaded mounting member positioned on a rear portion of the syringe to retain the syringe on the injector. The syringe preferably further includes a stop member to prevent rotation of the syringe relative to a threaded retaining member of the injector when the threaded retaining member is rotated relative to the threaded mounting member to engage the threaded mounting member and connect the syringe to the injector.

In a further aspect, the present invention provides an injector for injecting a fluid from a syringe. The syringe includes an elongated body, a mounting member positioned on a rear portion of the body, a plunger moveably positioned within the body of the syringe, and encoded syringe information. The injector preferably includes: a sensor to read the encoded syringe information and a powered drive member adapted to engage the plunger and control the movement of the plunger. The drive member preferably controls the movement of the plunger in accordance with the encoded syringe information.

In still another aspect, the present invention provides a method of connecting a syringe to an injector for injection of a fluid into a patient, the syringe including a plunger positioned therein and encoded syringe information. The method includes the steps of: connecting the syringe to the injector; having the injector read the syringe information; and having the injector control the motion of the plunger in a manner that is dependent upon the encoded syringe information.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a front-loading injector system10of the present invention is illustrated inFIGS. 1 through 4D. Injector system10includes a syringe100and an injector200. Injector housing210of injector200preferably includes a reciprocating piston220(see, for example,FIGS. 4A and 4C) therein which cooperates with a syringe plunger110disposed within an elongated cylindrical body120of syringe100to inject an injection fluid (for example, a liquid contrast medium) from the interior of syringe100into a patient. Piston220is preferably extendible and retractable via a powered means as known in the art (not shown) that is preferably contained within injection housing210and includes, for example, a motor or hydraulic system, including appropriate gearing (not shown). As also known in the art, injector200also preferably includes a motor controller for controlling operation of a motor and thereby controlling operation of piston220. The operation of injector200can, for example, be controlled by a computer150including a processing unit152and memory154.

As used herein to describe system10, the terms “axial” or “axially” refer generally to an axis A around which system10(including, for example, piston220and syringe10) is preferably formed (although not necessarily symmetrically therearound). The terms “proximal” or “rearward” refer generally to an axial direction toward the end of injector housing210opposite the end to which syringe10is mounted. The terms “distal” or “forward” refer generally to an axial direction toward a syringe tip124of syringe10. The term “radial” refers generally to a direction normal to axis A.

Piston220moves axially forward and rearward through an opening232in a retainer230that includes a face plate240that is attached to or formed integrally with the front wall of housing210. As illustrated inFIGS. 1through3, retainer230preferably further includes a generally annular retaining member250that rotatably seats in a seating area234in retainer230. Retaining member250may, for example, include threading252on an inner surface thereof. Threading252cooperates with threading130positioned on a rearward portion of syringe body120to load and retain syringe100on injector200.

During loading of syringe100onto injector200, an operator inserts the rear portion of syringe100within opening232in face plate240so that, for example, one or more guide or stop members140are aligned with corresponding slot(s)260formed in face plate240. Retainer230may include a sensor bank264(seated, for example, in seating area266formed in face plate240) including a loading sensor or sensors270to sense the presence of syringe100and begin rotation of retaining member250to draw syringe100rearward with the opening in face plate240and create a secure engagement between syringe100and injector200. Many types of sensors as known in the art can be used as loading sensor(s)270. For example, loading sensor270can include a switch mechanism that is triggered by contact with stop member240. Alternatively, a manual switch (not shown) located on injector200or remote therefrom can be used to begin rotation of retaining member250once syringe100is in position.

FIG. 2Billustrates another embodiment of a syringe100A which cooperates with an adapter100B to connect to retainer. Adapter100B preferably includes threading130B, a guide or stop member140B and a flange160B that cooperate with retainer230as described above. Syringe100A may, for example, be a syringe as disclosed in U.S. Pat. No. 5,383,858 that connects to adapter100B in the manner that is described in U.S. Pat. No. 5,383,858 for connection of syringe100A to the injector of U.S. Pat. No. 5,383,858. In that regard, adapter100B includes retaining flanges (not shown) for receiving mounting flanges102A on the rearward end of the syringe100A. Syringe is manually rotated to engage the mounting flanges behind the associated or cooperating flanges on the adapter. Use of an adapter such as adapter100B enables use of a wide variety of syringes with the retainers of the present invention. With use of an adaptor, many types of syringes can be used to take advantage of the benefits of the injectors of the present invention.

Similarly, syringe100can easily be adapted for use with other injectors through use of an adapter such as adapter100C illustrated inFIG. 2C. Adapter100C can, for example, be designed to adapt syringe100for use in current manually loaded injectors such as described in U.S. Pat. No. 5,383,858. In that regard, adapter100C includes on a rearward end thereof retaining flanges102C that cooperate with the injector of U.S. Pat. No. 5,383,858 as described therein. On a front end thereof, adapter100C also includes an opening having a slot140C on the perimeter thereof through which guide member140passes to allow threading130of syringe100to engage threading130C of adapter100C to connect syringe100to adapter100C.

Sensor270or a manual switch as described above is preferably in communication with a power source such as an electric motor300so that motor300is switched on when syringe100is sensed by sensor270or when an operator selects the manually operated loading switch. In the embodiment ofFIGS. 1 through 4D, motor300is in operative connection with a gear310that is rotatably seated within a seating area280within retainer230to mesh with an outer geared surface254of retaining member250. Rotational motion of motor300is thus translated to rotation of rotating member250. Abutment of stop member140with the sides of slot260prevents syringe100from rotating relative to retaining member250when retaining member250is rotated to engage syringe threading130, thereby facilitating threaded engagement between retaining member250and syringe100. Limit switches (not shown), position sensors (not shown) and/or measurement of motor current of motor300can, for example, be used to control movement of retaining member250to ensure that syringe100A is properly loaded and excess stresses are not placed thereon.

Using cooperating threaded elements, syringe100can be loaded upon injector200in either a powered or manual manner. For example, if it is desirable to load syringe100onto injector200in a manual manner, retaining member250can be advanced to its forward position and held in that position. Syringe100can then me manually rotated to engage threading130with threading252of retaining member250.

Syringe100preferably also includes a generally annular flange160positioned forward of threading130. Flange160is preferably drawn securely against a portion of a front or forward surface of face plate240when syringe100is fully engaged within injector200. Flange160assists in forming a secure interference fit and also assists in preventing leakage of fluids into injector200.

Upon secure connection of syringe100to injector200as described above (in either a powered or manual loading procedure), a preferably releasable connection between plunger110and piston220is preferably made. A number of manners of forming a releasable connection between a plunger and a piston in a front-loading injector system are disclosed in U.S. Pat. Nos. 4,677,980, 5,383,858, 5,873,861 and 5,947,935, the disclosures of which are incorporated herein by reference. In the embodiment illustrated inFIGS. 4A through 4D, plunger110includes capture legs112that extend rearward from a rear surface of plunger110. Capture legs112include radially inward extending abutment members114that cooperate with a radially outward extending flange224of a piston head222to releasably connect plunger110to piston220. Capture legs112are cantilevered such that, when abutment members114are contacted by flange224upon forward advancement of piston220relative to plunger110, capture legs112are forced radially outward to allow piston head222to pass therebetween. Capture legs112spring radially inward once flange224passes abutment members114so that abutment members114engage flange224to releasably connect plunger110to piston220as illustrated inFIG. 4A. Flange224is preferably generally circular in shape so that the relative angular positions (as rotated about the common axis A) of plunger110and drive member220are unimportant to the ability to connect plunger110and drive member220.

In the embodiment ofFIGS. 4A through 4D, plunger110is preferably released from piston220by forward advancement of a release cylinder400that contacts capture legs112to force capture legs radially outward as illustrated inFIG. 4B. Piston220can then be drawn rearward to release plunger110from connection therewith. During operation of injector200, release cylinder400is in a retracted position as illustrated inFIG. 4Aand travels generally in unison with piston220, which is disposed within release cylinder400. Upon, for example, completion of an injection procedure, an operator can preferably depress a release switch212on injector housing210to initiate release of plunger110(and, preferably, release of syringe100from injector200). Upon depression of switch212, a plunger release motor410is preferably activated to advance release cylinder400to release plunger110.

Upon release of the connection of plunger110from piston220via release switch212, syringe100can be released from injector200by simply activating retaining member250to disconnect threading252thereof from threading130on the rear of syringe100. Preferably, such activation of retaining member250occurs automatically upon release of plunger100. Upon disconnection, syringe100preferably remains releasably seated in opening232of retainer230until removed by the operator.

Depending, for example, upon the nature of syringe110, and regardless of whether syringe100is loaded in a powered or manual manner, different operations may be performed upon connection of syringe100to injector200. It is particularly advantageous to control and/or automate certain preinjection procedures. For example, in the case of an empty syringe, it may be desirable to advance plunger110within syringe100to expel air therefrom and, subsequently, to draw injection fluid into syringe100. One or more of these steps may be accomplished through manual control by an operator or automatically via, for example, control from computer150.

In the case of a prefilled syringe, on the other hand, after connection of syringe100to injector200, caution should be exercised in advancing piston220any farther forward than required to connect piston220to plunger110. Excess forward motion of piston110will result in expelling injection fluid in a prefilled syringe.

Although the determination of the type of syringe connected to injector200can be made by the operator and injector200controlled appropriately, it is also possible to have injector200detect the type of syringe100, the contents thereof, the volume thereof etc. In that regard, one or more sensors290can be positioned on retainer230to detect syringe information that can be encoded on, for example, area142on syringe100(seeFIG. 3). Methods and systems for reading encoded syringe information are disclosed, for example, in U.S. Pat. No. 5,383,858 and PCT International Patent Application Serial No. PCT/US99/13360 filed Jun. 15, 1999, assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference. In one embodiment, sensors270and290are combined in a single sensor.

Moreover, in the case that a prefilled syringe is connected to injector200, the position of syringe plunger100may be detected by injector200to ensure that piston220is not advanced too far forward in connecting piston220to plunger110. The detection of plunger position can be accomplished in numerous ways. For example, motor current in injector200can be measured. The greater resistance to advancement of piston220upon contact thereof with plunger110can be sensed by measuring motor current and the advancement of piston220stopped. Likewise, a sensor can be placed on piston head222and or plunger110to detect contact of piston220with plunger110. For example, plunger110can include a light source116and a light sensor116′ (seeFIG. 4B). Connection of drive member220with plunger110will prevent light from light source116from reaching light sensor116′ and thereby provide an indication that connection has been made.

FIG. 4Eillustrates an alternative embodiment of a plunger110′ having capture members112′. In this embodiment, plunger110′ includes a rearward projecting element114′ that inserts into a passage222′ of a piston head224′ of a piston220′ upon connection of piston220′ and plunger110′. Disposed on one side of passage222′ is a light source226′, and on an opposing side thereof is a light sensor226″. Connection of drive member220′ with plunger110′ will cause projecting element114′ to enter passage222′ and prevent light from light source226′ from reaching light sensor226″, thereby providing an indication that connection has been made.

During loading of syringe100onto injector200as described above, an operator inserts the rear portion of syringe100within opening232. Loading sensor(s)270sense the presence of syringe100and begin loading syringe100upon injector200. The type of syringe is sensed by sensor290. Docking of piston220to plunger110, as described above, is preferably automatically initiated upon loading of syringe100into injector200. If injector200senses that an empty syringe has been loaded thereupon, injector200preferably advanced piston220to engage plunger110. After engagement of plunger110, piston220preferably continues to advance forward to expel air from syringe100and prepare syringe100for filling with injection fluid. Should injector200sense that a prefilled syringe has been loaded thereupon, however, piston220preferably engages plunger110and discontinues any further advancement until an injection procedure begins.

An alternative embodiment of a syringe mounting and retaining mechanism is illustrated inFIGS. 5A and 5B. In this embodiment, syringe600includes a generally annular mounting flange630formed on a rearward portion thereof. Syringe600also includes a generally annular flange or sealing member650formed forward of mounting flange630. Injector700includes a retainer730to securely connect syringe600to injector700. Retainer730includes, for example, a retaining member750. Retaining member750preferably includes a plurality of capture members752that are preferably positioned around the circumference of retaining member750. Each of capture members752preferably includes an abutment member754on a forward end thereof that is adapted to form an abutting connection with mounting flange730.

Before loading of syringe600on injector700, capture members752are in an open position as illustrated inFIG. 5Ain which capture members752are flared radially outward so that mounting flange630can pass by abutment members754. Once syringe600is placed in loading position by an operator, retaining member750is drawn rearward, for example, via cooperation of threading756with a cooperating threaded member (not shown). As retaining member750is drawn rearward, the radially outer edges of capture members652contact a radially inward extending surface732of retainer730, thereby drawing abutment members754radially inward to engage mounting flange630.

After abutment members754engage mounting flange630and retainer650is drawn further rearward, syringe600is drawn rearward until flange650is drawn into secure engagement with a front surface of retainer630as illustrated inFIG. 5B. Sensors (not shown) can be provided to ensure that secure engagement has been achieved. Capture members752and abutment members754are preferably forced radially inward by abutment with a beveled or chamfered surface760of retainer730. Syringe600is thereby securely engaged within injector300. To release syringe600, retaining member650is moved forward so that capture members752are allowed to expand in a radial outward manner as illustrated inFIG. 5A.

Although the present invention has been described in detail in connection with the above examples, it is to be understood that such detail is solely for that purpose and that variations can be made by those skilled in the art without departing from the spirit of the invention except as it may be limited by the following claims.