WO2012112347A1

WO2012112347A1 - Monitoring operation of a power injector via motor current measurement

Info

Publication number: WO2012112347A1
Application number: PCT/US2012/024216
Authority: WO
Inventors: Charles L. WINN; Todd M. SUCHECKI; Mohd Touhid KHAN
Original assignee: Acist Medical Systems, Inc.
Priority date: 2011-02-15
Filing date: 2012-02-08
Publication date: 2012-08-23
Also published as: CN103379928A; US20120204997A1; JP2014510575A; EP2675497A1

Abstract

Embodiments of the present invention monitor resistance to the movement of the ram and detect one or more injector operation conditions based on that resistance. Some embodiments automatically detect whether a syringe is present in each syringe chamber of an injector based on ram movement resistance so that subsequent steps in the inject process can be automatically initiated or delayed based on the presence or absence of the syringe(s). Other injector operation conditions that can be detected include the injector's syringe sleeve being misaligned for operation, the syringe's wiper being misaligned within the syringe barrel, an occlusion within the syringe, overpressure during injection, and so on. A common way to measure resistance of the ram's movement is how much current is required by the motor driving the ram.

Description

MONITORING OPERATION OF A POWER INJECTOR VIA MOTOR CURRENT MEASUREMENT

TECHNICAL FIELD

This document relates generally to the operation of medical fluid injection systems.

BACKGROUND

In many medical environments, a medical fluid is injected into a patient during diagnosis or treatment. One example is the injection of contrast media into a patient to improve computed tomography (CT), angiographic, magnetic resonance (MR) or ultrasound imaging using a powered fluid injection system.

The contrast media is typically injected into the catheter by an automated injection system. While the apparatus for injecting the contrast media can vary, most systems include a syringe operatively connected with the catheter. The injector includes a syringe chamber that houses a syringe, which can typically be reused several times. The injector also includes a ram that is reciprocally moveable within the syringe chamber. The contrast media is suctioned into the syringe when the ram is moved to create a partial vacuum within the syringe. A reversal of the ram direction first forces air out of the syringe and then delivers the contrast media to the catheter at a rate and volume determined by the speed of movement of the ram.

Additionally, such procedures can include the injection of fluids other than the contrast media. For example, a saline flush and/or the injection of fluid medications may be desired. Accordingly, injectors can include multiple syringe chambers for housing multiple syringes, with the injector having a ram for each syringe chamber. These additional syringe chambers and rams can function the same way as discussed above, with the only difference being that fluids other than contrast media are suctioned into and delivered out of the respective syringes. Accommodating multiple syringes with an injector is taught by U.S. Patent Application No. 12/094,009 (Publication No. 2009/0149743), titled Medical Fluid Injection System, which is assigned to the assignee of the present application and is hereby incorporated by reference in its entirety.

The process of filling a syringe with medical fluid and injecting the medical fluid is preferably as automated as possible so as to decrease the amount of time associated with injector setup and/or to minimize the incidence of operator error. Increasing setup speed can be particularly important in CT applications. One step that commonly produces operator error is loading a syringe into the proper syringe chamber. In some instances, the operator loads the syringe into the wrong syringe chamber (e.g., in procedures in which less than all of the syringe chambers will be utilized). In some instances, the operator attempts to load the syringe in the proper syringe chamber but accidentally misaligns the syringe, leaving the syringe unfit for subsequent processes. In some instances, the operator is so preoccupied by the other tasks of preparing a patient for the procedure that he/she simply forgets to load the syringe. Problems arise when the automated injection process commences without the syringe(s) being properly loaded into the syringe chamber(s).

BRIEF SUMMARY

Embodiments of the present invention monitor resistance to the movement of an injector's ram and detect one or more operation conditions of the injector based on that resistance. Some embodiments automatically detect whether a syringe is present in one or more syringe chambers of an injector based on ram movement resistance so that subsequent steps in the syringe-fill process can be automatically initiated or delayed based on the presence or absence of the syringe(s). Other injector operation conditions that can be detected include the injector's syringe sleeve being misaligned for operation, the syringe's wiper being misaligned within the syringe barrel, an occlusion within the syringe, overpressure during injection, and so on. A preferred way of measuring resistance of the ram's movement is how much current is required by the motor driving the ram.

In embodiments in which ram movement resistance is used to detect syringe presence, the ram of the injector can be advanced into the respective syringe chamber of the injector (e.g., as it normally would in a syringe-fill process), and the presence or absence of a syringe can be determined based on how much the ram's movement is resisted. If such movement is resisted by a significant amount (e.g., more than a threshold amount), it can be concluded that a syringe's wiper is impeding the movement and thus a syringe is present. If such movement is resisted by a lesser amount, it can be concluded that there is no syringe wiper to impede the movement and thus no syringe is present.

Embodiments of the present invention can provide one or more of several advantages. For example, some such systems can be advantageous as compared to systems that use optical or mechanical sensors to detect syringe presence. In such systems, medical fluid (especially contrast media) can become caked onto the equipment in a manner that interferes with the operation of the sensors, rendering them unreliable. In contrast, embodiments of the present invention can detect syringe presence based on parameters that are very readily measurable and repeatable. An important advantage provided by many embodiments of the present invention is improved efficiency and time savings. Detecting many of the injector operation conditions discussed herein earlier rather than later can avoid wasting significant amounts of time. Moreover, increasing the automation of such procedures can enable operators to perform various processes in parallel rather than in series. Such time savings can be especially important in a setting (e.g., CT) in which an operator must maintain a strict schedule of completing procedures within fixed periods of time. Some embodiments of the present invention involve monitoring for injection operation conditions in order to avoid damage to the injector itself (e.g., monitoring for a misaligned syringe sleeve). Some embodiments involve monitoring for injector operation conditions in order to enhance patient safety (e.g., monitoring for overpressure conditions during injection). These and/or other advantages can be provided by embodiments of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

The following drawings are illustrative of particular embodiments of the present invention and therefore do not limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, wherein like numerals denote like elements.

Fig. 1 is a perspective view of an illustrative injector in accordance with embodiments of the present invention.

Fig. 2A is a perspective view of syringe/plunger assemblies of the illustrative injector of Fig. 1, with a syringe present in one of the syringe/plunger assemblies.

Fig. 2B is a perspective view of syringe/plunger assemblies of the illustrative injector of Fig. 1, with no syringe present in one of the syringe/plunger assemblies.

Fig. 3A is a schematic view of an illustrative syringe/plunger assembly in accordance with embodiments of the present invention, with a syringe present.

Fig. 3B is a schematic view of the illustrative syringe/plunger assembly of Fig. 3 A, with no syringe present.

Fig. 4 is a schematic view of an illustrative syringe/plunger assembly in accordance with embodiments of the present invention, with no syringe present. Fig. 5 is a block diagram of an illustrative injection system in accordance with embodiments of the present invention.

Fig. 6 is a flow chart of an illustrative method in accordance with embodiments of the present invention.

DESCRIPTION

The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical illustrations for implementing exemplary embodiments of the present invention. Examples of constructions, materials, dimensions, and manufacturing processes may be provided for selected elements, and all other elements employ that which is known to those of skill in the field of the invention. Those skilled in the art will recognize that many of the examples provided have suitable alternatives that can be utilized.

Fig. 1 shows an illustrative dual-syringe injector 10, which includes a main control panel 15 and an injection head 20. The injector 10 can inject multiple medical fluids through a catheter into a patient's vasculature. As shown, a first medical fluid reservoir 25 is attached to the injection head 20, and a second medical fluid reservoir 30 is also attached to the injection head 20. In preferred embodiments, medical fluid reservoir 25 comprises a bottle of sterile contrast media, and medical fluid reservoir 30 comprises a bag of sterile diluent, such as saline. While the injector 10 of Fig. 1 is a dual-syringe injector, it should be emphasized that embodiments of the present invention can involve other types of injectors, such as single- syringe injectors or other kinds of injectors.

The injection head 20 can include various components. For example, the injection head 20 includes a secondary control panel 35, first and second syringe/plunger assemblies 40 and 45, and various valve/air detect assemblies. The injector 10 is capable of drawing fluid from medical fluid reservoir 25 into syringe/plunger assembly 40 via tubing 50, and is further capable of drawing fluid from medical fluid reservoir 30 into syringe/plunger assembly 45 via tubing 55. Syringe/plunger assembly 40 is capable of expelling medical fluid into output tubing 60, and syringe/plunger assembly 45 is capable of expelling medical fluid into output tubing 65. The output tubing 60, 65 can include a reusable portion and a single- use portion. In this way, the single-use portions of the output tubing 60, 65 are coupled to the patient catheter and are discarded after a patient procedure. The reusable portions are those portions of the tubing that are directly coupled to the outputs of the syringe/plunger assemblies 40, 45. The reusable portions and single-use portions may be coupled by fluid connectors.

The injector 10 further includes both a main control panel 15 and also a secondary control panel 35. An operator of the injector 10 may use the main control panel 15 to set up one or more parameters of an injection procedure prior to initiation of the procedure. The operator may also use the main control panel 15 to modify one or more aspects, parameters, etc. of an injection procedure during the procedure, or may also use the main control panel 15 to pause, resume, or end an injection procedure and begin a new procedure. The main control panel 15 can display various injection-related information to the operator, such as flow rate, volume, pressure, rise time, procedure type, fluid information, and patient information. The secondary control panel 35 can provide a subset of functions provided by the main control panel 15. For example, the operator may use the secondary control panel 35 to manage injector setup. The operator may interact with the secondary control panel 35 to manage the setup of the injector. The secondary control panel 35 may display guided setup instructions that aid in this process.

Figs. 2A-2B show the syringe/plunger assemblies 40, 45 in greater detail. In Fig. 2A, a syringe 70 is housed by a syringe chamber 75 of syringe/plunger assembly 45. In Fig. 2B, no syringe is present in the syringe chamber 75. If a given injection procedure calls for syringe 70 being in syringe chamber 75, the configuration of Fig. 2A is proper. Similarly, if the procedure calls for no syringe in syringe chamber 75, the configuration of Fig. 2B is proper. On the other hand, if the procedure calls for no syringe in syringe chamber 75, the configuration of Fig. 2A is improper, and if the procedure calls for a syringe in syringe chamber 75, the configuration of Fig. 2B is improper. As is discussed in greater detail below, it can be advantageous to determine automatically whether syringes are loaded into the syringe chambers as called for by the particular procedure.

The functionality of an exemplary syringe/plunger assembly 105 is discussed in connection with Figs. 3A-3B. As shown, the syringe/plunger assembly 105 includes a syringe chamber 110, a ram 115, a spud 120, and a motor 125. The syringe chamber 110 can include an inlet port 126 and an outlet port 127. In Fig. 3A, a syringe 130 is housed in the syringe chamber 110. The syringe 130 can include a wiper 135 that is engaged by the spud 120 of the syringe/plunger assembly 105 during injection operations, as is discussed in greater detail below. The syringe 130 can include an inlet opening 136 that coincides with the inlet port outlet port 127 of the syringe chamber 110. In Fig. 3B, no syringe is present in the syringe chamber 110.

The motor 125 can include a linear actuator that drives the ram 115 in both an advancing direction AD and a retracting direction RD. The motor 125 can be configured to drive the ram 115 through substantially the entire syringe chamber 110, from the proximal end 111 to the distal end 112. The degree to which movement of the ram 115 is resisted can impact how hard the motor 125 must work to drive the ram 115 and, in turn, how much current is required by the motor 125 to drive the ram 115. In many embodiments, the current required by the motor 125 is directly proportional to the resistance of the movement of the ram 115. For example, determining the resistance pressure can involve a form of the slope/intercept formula: y = mx + b. In this formula, y would represent motor current, x would represent resistance pressure, and m and b would be constants derived for each injector during the manufacturing/calibration process. Accordingly, solving for x would result in the following formula: x = (y-b)/m.

Referring to Fig. 3 A, upon confirmation that the syringe 130 is present in the syringe chamber 110, the motor 125 can drive the ram 115 in the advancing direction AD until the spud 120 engages the wiper 135 of the syringe 130. As the ram 115 encounters the wiper 135, resistance to the movement of the ram 115 increases, thereby increasing the amount of current required by the motor 125. As the ram 115 presses the spud 120 into the wiper 135, the periphery of the wiper 135 folds over the spud 120 to create a flange 140. In this way, the ram 115 can push the wiper 135 in the advancing direction AD and pull the wiper 135 in the retracting direction RD.

When the ram 115 has engaged the wiper 135, the syringe 130 can be filled with medical fluid, and the medical fluid can be injected into a patient's vasculature through a catheter. To fill the syringe 130 with medical fluid, the motor 125 can drive the ram 115 in the advancing direction AD until the leading edge of the wiper 135 is in proximity to the distal end 112 of the syringe chamber 110. During this step, frictional forces between the wiper 135 and the inner wall of the syringe 130 resist the movement of the ram 115. In preferred embodiments, this frictional force can be approximately 55 to 65 pounds. The outlet port 127 of the syringe chamber 110 can be sealed, and the inlet port 126 can be in fluid communication with a medical fluid source. The motor 125 can then retract the ram 115 and the wiper 135 in the retracting direction RD, thereby creating negative pressure within the syringe 130 between the wiper 135 and the distal end 112, which draws medical fluid into the syringe 130 through the inlet port 126 and the inlet opening 136. As the ram 115 and wiper 135 are fully retracted, the syringe 130 is filled with medical fluid. To inject the medical fluid from the syringe 130 into a patient's vasculature through a catheter, the inlet port 126 can be sealed, and the outlet port 127 can be in fluid communication with the catheter. Then the motor 125 can again drive the ram 115 and the wiper 135 in the advancing direction AD to press the medical fluid out of the syringe 130 through the outlet opening 137 and the outlet port 127.

Fig. 4 shows an illustrative syringe/plunger assembly 205 that can be used in some embodiments of the present invention. The motor 125 and ram 115 of Fig. 4 can be the same as those in Figs. 3A-3B. As can be seen, however, the spud 220 and the distal end 212 of the syringe chamber 210 of Fig. 4 are different from those in Figs. 3A-3B. Referring to Fig. 4, the leading/distal edge of the spud 220 has a conical shape, which corresponds to the shape of the distal end 212 of the syringe chamber 210. The motor 125 can drive the ram 115 in the advancing direction AD or the retracting direction RD, thereby driving the spud 220 between the proximal end 211 and the distal end 212 of the syringe chamber. Unlike the syringe chamber 110 of Figs. 3A-3B in which the inlet port 126 is separate from the outlet port 127, the syringe chamber 210 of Fig. 4 includes a single inlet/outlet port 228 through which medical fluid can be guided in either direction.

Fig. 5 is a block diagram of an illustrative injection system 400 in accordance with embodiments of the present invention. The injection system can include an injector 405 and an injector control system 410. The injector 405 can include one or more syringe chambers, along with one or more rams and one or more motors. The syringe chambers, rams, and motors can have the same or similar attributes as those discussed elsewhere herein.

The injector control system 410 can include a programmable processor 415 and a storage device 420, which can store various software modules designed for specific functionality. As shown in Fig. 5, the storage device 420 includes a ram motion data module 425, a resistance detection module 430, an operation condition detection module 435, and an inject process module 440. The software modules stored by the storage device 420 can vary depending on a variety of factors, such as the kind of injector 405, the kind of inject process, and so on. Many additional software modules can be stored by the storage device 420 and/or the functionality of the various software modules can be modified to fit the particular application. When executed by the programmable processor 415, the ram motion data module 425 can cause the programmable processor 415 to collect a set of ram motion information for each ram indicating that that ram is moving in an advancing or retracting direction in the syringe chamber. The inject process module 440 can instruct the programmable processor 415 to move the ram in accordance with an injector operation process (e.g., a syringe-fill process, a preliminary saline injection to check for extravasation, etc.). The ram motion data module 425 can assist the programmable processor 415 in confirming that the ram is indeed moving. In some embodiments, the ram motion information includes the location of the ram (e.g., the location of the spud) relative to a reference point, such as the proximal or distal end of the syringe chamber. For example, to detect whether a syringe is present, the injector control system 410 can confirm whether the spud has advanced far enough from its resting position such that it would encounter the syringe's wiper if the syringe were present. In another example, to detect if the syringe's wiper is misaligned, the injector control system 410 can assess ram resistance levels when the spud is located near the distal end of the syringe chamber (where the leading edge of the misaligned wiper would first encounter the distal end of the syringe). In some embodiments, the ram motion information includes the duration of time that the ram has been moving (e.g., from a reference time marker such as when the ram first moved from rest, when the ram began retracting, etc.). For example, if it is known that the ram begins retracting X seconds into the syringe-fill process, the injector control system 410 can begin monitoring ram resistance after X seconds have elapsed to determine whether the proper vacuum is being created within the syringe chamber. In some embodiments, the ram motion information includes a rate at which the ram is moving or accelerating. In some embodiments, the ram motion information includes other information related to the ram's movement that may be relevant to one or more injector operation conditions.

When executed by the programmable processor 415, the resistance detection module 430 can cause the programmable processor 415 to collect a set of resistance information for each ram indicating how much the movement of that ram in the advancing or retracting direction is resisted. For systems in which one or more motors are configured to drive one or more rams, the first set of resistance information can include how much current is required by the motor(s) to drive the ram(s). In some embodiments, the resistance information is based on parameters other than motor current, such as the acceleration of the ram. When executed by the programmable processor 415, the operation condition detection module 435 can cause the programmable processor 415 to detect one or more injector operation conditions. The operation condition detection module 435 can cause the

programmable processor 415 to receive the set(s) of ram motion information from the ram motion data module 425 and to receive the set(s) of resistance information from the resistance detection module 430. The programmable processor 415 can then, as caused by the operation condition detection module 435, determine whether one or more of several injector operation conditions are present based on the set(s) of ram motion information and the set(s) of resistance information.

The operation condition detection module 435 can cause the programmable processor

415 to monitor for one or more of a variety of injector operation conditions. For example, one such condition is the syringe sleeve being misaligned for operation. The syringe sleeve acts as a door for permitting access to the syringe chamber. If the syringe sleeve is not closed properly (e.g., due to misalignment of the syringe), the spud can press against it during ram advancement or pull against it during ram retraction and cause significant damage. The operation condition detection module 435 can cause the programmable processor 415 to monitor for the ram improperly contacting the syringe sleeve based on the ram motion information (e.g., is the spud near the proximal or distal end of the syringe chamber?) and the resistance information (e.g., has the motor current spiked to an unusually high level?).

Another example of a condition that can be watched for by the programmable processor 415, as prompted by the operation condition detection module 435, is whether there is an occlusion in the syringe (e.g., due to crusted contrast material, syringe manufacturing abnormalities, etc.). If the ram motion information and the resistance information indicate, for example, that there is a heightened resistance to the ram's movement when the ram is located in a position that would ordinarily result in minimal resistance, the operation condition detection module 435 can cause the programmable processor 415 to suggest that the syringe may have an occlusion. Another example of a monitorable condition is whether the syringe wiper is misaligned within the syringe barrel. As alluded to above, if the syringe wiper is not alighted coaxially with the syringe barrel, one part of the syringe wiper can contact the distal end of the syringe barrel first. This can cause the syringe wiper to be crushed, which results in significant time wasting due to having to reload a new syringe and restart the process. If the ram motion information and the resistance information indicate, for example, that there is a heightened resistance to the ram's movement as the spud approaches the distal end of the syringe chamber, the operation condition detection module 435 can cause the programmable processor 415 to suggest that the syringe wiper is misaligned.

In preferred embodiments, the operation condition detection module 435 can cause the programmable processor 415 to determine whether a syringe is present in the syringe chamber(s) by drawing conclusions based on the resistive pressure experienced by the ram in advancing. If the first set of resistance information indicates that the movement of the first ram in the advancing direction is resisted by a predetermined amount of pressure or more, the operation condition detection module 435 can cause the programmable processor 415 to conclude that a syringe is present in the first syringe chamber. In this situation, it can be concluded that the resistive pressure is applied by the wiper of a syringe, meaning that a syringe is indeed present. If the first set of resistance information indicates that the movement of the first ram in the advancing direction is resisted by less than the predetermined amount of pressure, the operation condition detection module 435 can cause the programmable processor 415 to conclude that no syringe is present in the first syringe chamber. In this situation, it can be concluded that the ram is advancing unimpeded by a syringe wiper, meaning that no syringe is present.

The amount of ram resistance pressure that is indicative of syringe presence can vary from one embodiment to another. In many embodiments, approximately 55-65 psi is required to move the syringe wiper from its resting position. Thus, in such embodiments, setting the predetermined amount of pressure to a value below 55 psi (e.g., 10 psi) can provide the desired effect.

When executed by the programmable processor 415, the inject process module 440 can cause the programmable processor 415 to perform a variety of functions relating to injecting medical fluids into a patient's vasculature. As discussed it is preferable that the inject process be as automated as possible. Automatically detecting the presence or absence of a syringe in the syringe chamber(s) can enhance the inject process. In particular, in some embodiments, the inject process module 440 can cause the programmable processor 415 to automatically begin a syringe-fill process if it is determined that a syringe is present in a respective syringe chamber. In some embodiments, the inject process module 440 can cause the programmable processor 415 to halt the inject process and alert an operator if it is determined (a) that no syringe is present in a respective syringe chamber, (b) that the syringe sleeve is misaligned, (c) that the syringe wiper is not coaxial with the syringe barrel, (d) that there is an occlusion in the syringe, etc. In some embodiments, the operation condition detection module 435 can cause the programmable processor 415 to monitor for injector operation conditions while the injector is injecting contrast media into a patient's vasculature. For example, one such condition is injection overpressure. If the ram motion information and/or the resistance information indicate an abnormally high resistance during injection, the inject process module 440 can cause the programmable processor 415 to halt the process and alert an operator. This and similar functions of the operation condition detection module 435 can provide significant enhancements to patient safety.

The injector control system 410 can be located in a variety of locations. In preferred embodiments, the injector control system 410 can be located in the injector 405 itself. In some embodiments, the injector control system 410 can be located separately from the injector 405. In some embodiments, the injector control system 410 can be located on a server that is remote from the injector 405 and can communicate with the injector 405 via a network 445 (e.g., the Internet). In such embodiments, the operator can enter a command into the control panel, components in the injector can package the command and send it over the network 445 to the injector control system 410, and the injector control system 410 can initiate a responsive action and communicate that action to the injector 405 via the network 445.

Fig. 6 shows an illustrative method that can be implemented in accordance with embodiments of the present invention. As shown, the method includes providing an injector with attributes like those discussed elsewhere herein (505). The method of Fig. 6 involves at least two syringe chambers, motors, and rams, but it should be understood that the principles shown and discussed herein can be incorporated into a method for use with a single-syringe injector.

The method of Fig. 6 includes moving a first ram (510) and moving a second ram

(515). For example, the method can include causing the first ram to move a first distance in the advancing direction in a first syringe chamber of the injector. Similarly, the method can include causing the second ram to move a second distance in the advancing direction in a second syringe chamber of the injector. In preferred embodiments, causing the ram(s) to move in the advancing direction can include driving the ram(s) with motor(s).

As the rams are moved (510, 515), resistance of that movement can be measured. The method can include measuring how much the movement of the first ram in the advancing direction is resisted (520). Similarly, the method can include measuring how much the movement of the second ram in the advancing direction is resisted (525). As is discussed elsewhere herein, in embodiments in which causing the ram(s) to move in the advancing direction involve driving the ram(s) with motor(s), measuring how much that movement is resisted can include measuring how much current the motor(s) require to drive the ram(s).

In the method of Fig. 6, a determination can be made whether the first ram has moved a first distance (530) and whether the second ram has moved a second distance (535). In many embodiments, a ram must move at least a threshold distance before any conclusion can be drawn regarding the presence or absence of a syringe in the respective syringe chamber. For example, if the ram moves less than the threshold distance, it may not yet have moved to where a syringe wiper would be. In that example, a false conclusion could be drawn that no syringe is present. For this and other similar reasons, many embodiments involve determining whether each ram has moved a threshold distance. If the first ram has not moved a first distance, the first ram can again be moved (510), and if the second ram has not moved a first distance, the second ram can again be moved (515).

If the rams have moved the threshold distance (e.g., far enough to encounter a syringe wiper if present), determinations can be made regarding the presence/absence of syringes in the respective syringe chambers. A determination can be made whether the resistance of the first ram's movement exceeds a first predetermined amount (540) and whether the resistance of the second ram's movement exceeds a second predetermined amount (545). If the movement of the first ram in the advancing direction is resisted by less than the first predetermined amount of pressure, it can be concluded that no syringe is present in the first syringe chamber (550). On the other hand, if the movement of the first ram in the advancing direction is resisted by the first predetermined amount of pressure or more, it can be concluded that a syringe is present in the first syringe chamber (555). Similarly, if the movement of the second ram in the advancing direction is resisted by the second

predetermined amount of pressure or more, it can be concluded that a syringe is present in the second syringe chamber (560). On the other hand, if the movement of the second ram in the advancing direction is resisted by less than the second predetermined amount of pressure, it can be determined that no syringe is present in the second syringe chamber (565). In some embodiments, both the first predetermined amount of pressure and the second predetermined amount of pressure is approximately 10 psi.

In preferred embodiments, subsequent actions can automatically be taken based on the determination of whether syringes are present in the syringe chambers. As shown, if it is concluded that no syringe is present in the first syringe chamber (550), an operator can be alerted (570), and if it is concluded that no syringe is present in the second syringe chamber (565), an operator can be alerted (585). If it is determined that a syringe is present in the first syringe chamber (555), a syringe-fill process can automatically be begun for that syringe (575), and if it is determined that a syringe is present in the second syringe chamber (560), a syringe-fill process can automatically be begun for that syringe (580). Other subsequent actions may be taken based on whether syringes are present in the syringe chambers, depending on the type of injector, the injection procedure, and a variety of other factors.

It should be emphasized that the method shown in Fig. 6 is for illustration only. Any of the functionality discussed herein in connection with a system (see Fig. 5) may also be implemented by a method (and vice versa). Methods of monitoring for injector operation conditions other than syringe presence/absence would involve similar steps. The order of steps provided in the methods shown in Fig. 6 is provided for purposes of illustration only, and other orders that achieve the functionality recited are within the scope of the present invention. Any of the functionality discussed anywhere herein may be implemented in the method shown in Fig. 6.

Aspects and features of the present invention (e.g., as discussed herein in connection with the system of Fig. 5 and/or the method of Fig. 6) can be implemented in a computer- readable medium. The computer-readable medium can be an electronic, optical, magnetic, or other storage or transmission device capable of providing computer-readable instructions to a programmable processor. Examples of computer-readable media include a floppy disk, CD- ROM, magnetic disk, memory chip, ROM, RAM, an ASIC, a configured processor, all kinds of optical media, all kinds of magnetic tape or other magnetic media, or any other medium from which a computer processor can read instructions.

The medium can be programmed with instructions for preparing an injector (e.g., one with one or more attributes of injectors discussed elsewhere herein) for operation. The medium can include instructions for causing a programmable processor to receive one or more sets of ram advancement information, depending on how many rams and syringe chambers are included in the injector. Each set of ram advancement information can indicate that the corresponding ram of the injector has moved a given distance in the advancing direction in the corresponding syringe chamber of the injector. The ram advancement information can include information discussed herein in connection with moving the ram(s) in the advancing direction. The medium can include instructions for causing the programmable processor to receive one or more sets of resistance information, again depending on the number of rams and syringe chambers that are included in the injector. Each set of resistance information can indicate how much the movement of the corresponding ram in the advancing direction was resisted. In preferred embodiments, a set of resistance information can include how much current was required by a motor of the injector to drive the corresponding ram in the corresponding syringe chamber. The resistance information can include information discussed herein in connection with how the movement of the ram(s) in the advancing direction is resisted.

The medium can include instructions for causing the programmable processor to determine whether a syringe is present in each syringe chamber based on the set(s) of ram advancement information and the set(s) of resistance information. In preferred embodiments, the instructions for causing the programmable processor to determine whether a syringe is present in the syringe chamber(s) comprise instructions for causing the programmable processor to draw conclusions based on a predetermined amount of pressure. If a set of resistance information indicates that the movement of the corresponding ram in the advancing direction was resisted by a predetermined amount of pressure or more, the processor can conclude that a syringe is present in that syringe chamber. On the other hand, if a set of resistance information indicates that the movement of the corresponding ram in the advancing direction was resisted by less than the predetermined amount of pressure, the processor can conclude that no syringe is present in that syringe chamber. In particularly preferred embodiments, the predetermined amount of pressure to be used for each set of resistance information can be approximately 10 psi. Principles for making this determination are discussed in greater detail elsewhere herein.

As noted above, determinations can be made regarding subsequent actions based on whether a syringe is present or not. The medium can include instructions for causing the programmable processor to begin a syringe-fill process if it is determined that a syringe is present in the first syringe chamber. The medium can include instructions for causing the programmable processor to alert an operator if it is determined that no syringe is present in the first syringe chamber. Other instructions may be incorporated into the computer-readable medium for causing the programmable processor to take subsequent actions, as is discussed elsewhere herein. In some aspects, a computer-readable medium can be programmed with instructions for detecting a condition of an injector's operation. The medium can include instructions for causing a programmable processor to receive a first set of ram motion information regarding movement of a first ram of the injector in a first syringe chamber of the injector. The medium can include instructions for causing a programmable processor to receive a first set of resistance information indicating how much the movement of the first ram was resisted. The medium can include instructions for causing a programmable processor to determine whether a first injector operation condition is present based on the first set of ram motion information and the first set of resistance information. In preferred embodiments, the first set of resistance information can include how much current was required by a motor of the injector to drive the first ram in the movement of the first ram.

In some preferred embodiments, the first injector operation condition comprises a first syringe being present in the first syringe chamber. Some such embodiments include instructions for causing the programmable processor to conclude that the first syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram was resisted by a predetermined amount of pressure or more. Some such embodiments include instructions for causing the programmable processor to conclude that no syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram was resisted by less than the predetermined amount of pressure. In some such embodiments, the medium can further include instructions for causing the programmable processor to begin a syringe-fill process if it is determined that the first syringe is present in the first syringe chamber.

In some embodiments, the medium further comprises instructions for causing the programmable processor to determine whether a second injector operation condition is present. In preferred embodiments, the second injector operation condition is a second syringe being present in a second syringe chamber of the injector. In such embodiments, the programmable processor can receive a second set of ram motion information regarding movement of a second ram of the injector in the second syringe chamber of the injector. In such embodiments, the programmable processor can receive a second set of resistance information indicating how much the movement of the second ram was resisted. In many such embodiments, the programmable processor can determine whether the second syringe is present in the second syringe chamber based on the second set of ram motion information and the second set of resistance information. In some embodiments, the programmable processor can determine whether a second injector operation condition is present based on the first set of ram motion information and the first set of resistance information.

As discussed elsewhere herein, the injector operation condition(s) detected by embodiments of the present invention can be selected from a group consisting of: a first syringe being present in the first syringe chamber, a syringe sleeve of the first syringe chamber being not closed properly for operation, a wiper of the first syringe being misaligned with a barrel of the first syringe, an occlusion within the syringe, and overpressure during injection.

In some aspects, the present invention can be embodied in a method. The method can include providing an injector that has one or more of the characteristics discussed herein, including a first syringe chamber and a first ram. The method can include causing the first ram to move in an advancing direction and/or a retracting direction in the first syringe chamber. The method can include measuring how much the movement of the first ram is resisted. In many preferred embodiments, measuring how much the movement of the first ram is resisted includes measuring current supplied to a motor that drives the movement of the first ram. In many preferred embodiments, the method includes concluding that a first injector operation condition is present based on one or more characteristics of the movement of the first ram and on how much the movement of the first ram is resisted. Examples of injector operation conditions include a first syringe being present in the first syringe chamber, a syringe sleeve of the first syringe chamber being not closed properly for operation, a wiper of the first syringe being misaligned with a barrel of the first syringe, an occlusion within the syringe, and overpressure during injection.

As noted, in some embodiments, the first injector operation condition is that a first syringe is present in the first syringe chamber. The one or more characteristics of the movement of the first ram can include that the first ram has moved a first distance. How much the movement of the first ram is resisted can include that the movement of the first ram is resisted by a first predetermined amount of pressure or more. In some such embodiments, the method can further include automatically beginning a syringe-fill process if it is concluded that the first syringe is present in the first syringe chamber.

Some embodiments involve monitoring for multiple injector operation conditions.

Some injectors include a second syringe chamber and a second ram. In that context, the method can further include causing the second ram to move a second distance in the second syringe chamber and measuring how much the movement of the second ram is resisted. Additionally, in that context, the method can include concluding that a second syringe is present in the second syringe chamber if the movement of the second ram is resisted by a second predetermined amount of pressure or more or no syringe is present in the second syringe chamber if the movement of the second ram is resisted by less than the second predetermined amount of pressure.

In some aspects, the present invention can be embodied in an injection system. The injection system can include an injector, such as those discussed herein, which may include a first syringe chamber and a first ram. The injection system can also include an injector control system that has a processor and a storage device. The storage device can include a ram motion data module, a resistance detection module, and an operation condition detection module. When executed by the processor, the ram motion data module can cause the processor to collect a first set of ram motion information regarding movement of the first ram in the first syringe chamber. When executed by the processor, the resistance detection module can cause the processor to collect a first set of resistance information indicating how much the movement of the first ram is resisted. When executed by the processor, the operation condition detection module can cause the processor to receive the first set of ram motion information from the ram motion data module, receive the first set of resistance information from the resistance detection module, and determine whether a first injector operation condition is present based on the first set of ram advancement information and the first set of resistance information. In some preferred injection systems, the injector has a motor configured to drive the first ram, and the first set of resistance information includes how much current is required by the motor to drive the first ram. Examples of injector operation conditions include those discussed elsewhere herein. Examples of ram motion information include a location of the first ram relative to a reference point, a duration of time that the first ram has been moving, a rate at which the first ram is moving or accelerating, and so on.

In some embodiments, the operation condition detection module, when executed by the processor, can cause the processor to determine whether a first syringe is present in the first syringe chamber. In many embodiments, a conclusion may be drawn that a first syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram is resisted by a predetermined amount of pressure or more.

Similarly, in many embodiments, a conclusion may be drawn that no syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram is resisted by less than the predetermined amount of pressure. In some embodiments, the storage device further includes an inject process module that, when executed by the processor, causes the processor to automatically begin a syringe-fill process if it is determined that the first syringe is present in the first syringe chamber.

In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention as set forth in the appended claims. Thus, some of the features of preferred embodiments described herein are not necessarily included in preferred embodiments of the invention which are intended for alternative uses.

Claims

What is claimed is:

1. A computer-readable medium programmed with instructions for detecting a condition of an injector's operation, the medium comprising instructions for causing a programmable processor to:

(a) receive a first set of ram motion information regarding movement of a first ram of the injector in a first syringe chamber of the injector;

(b) receive a first set of resistance information indicating how much the movement of the first ram was resisted; and

(c) determine whether a first injector operation condition is present based on the first set of ram motion information and the first set of resistance information.

2. The medium of claim 1 , wherein the first injector operation condition comprises a first syringe being present in the first syringe chamber.

3. The medium of claim 2, wherein the instructions for causing the

programmable processor to determine whether the first syringe is present in the first syringe chamber comprise instructions for causing the programmable processor to conclude that (i) the first syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram was resisted by a predetermined amount of pressure or more or (ii) no syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram was resisted by less than the predetermined amount of pressure.

4. The medium of claim 2, further comprising instructions for causing the programmable processor to (d) begin a syringe-fill process if it is determined that the first syringe is present in the first syringe chamber.

5. The medium of claim 2, further comprising:

(d) receive a second set of ram motion information regarding movement of a second ram of the injector in a second syringe chamber of the injector;

(e) receive a second set of resistance information indicating how much the movement of the second ram was resisted; and (f) determine whether a second syringe is present in the second syringe chamber based on the second set of ram motion information and the second set of resistance information.

6. The medium of claim 1, wherein the first set of resistance information includes how much current was required by a motor of the injector to drive the first ram in the movement of the first ram.

7. The medium of claim 1, further comprising instructions for causing the programmable processor to (d) determine whether a second injector operation condition is present based on the first set of ram motion information and the first set of resistance information.

8. The medium of claim 1, wherein the first injector operation condition is selected from a group consisting of: a first syringe being present in the first syringe chamber, a syringe sleeve of the first syringe chamber being not closed properly for operation, a wiper of the first syringe being misaligned with a barrel of the first syringe, an occlusion within the syringe, and overpressure during injection.

9. A method comprising:

(a) providing an injector that includes (i) a first syringe chamber and (ii) a first ram;

(b) causing the first ram to move in an advancing direction and/or a retracting direction in the first syringe chamber;

(c) measuring how much the movement of the first ram is resisted; and

(d) concluding that a first injector operation condition is present based on one or more characteristics of the movement of the first ram and on how much the movement of the first ram is resisted.

10. The method of claim 9, wherein

the first injector operation condition is that a first syringe is present in the first syringe chamber,

the one or more characteristics of the movement of the first ram includes that the first ram has moved a first distance, and how much the movement of the first ram is resisted includes that the movement of the first ram is resisted by a first predetermined amount of pressure or more.

11. The method of claim 10, further comprising (e) automatically beginning a syringe-fill process if it is concluded that the first syringe is present in the first syringe chamber.

12. The method of claim 10, wherein:

the injector further includes (iii) a second syringe chamber and (iv) a second ram, and the method further comprises:

(e) causing the second ram to move a second distance in the second syringe chamber;

(f) measuring how much the movement of the second ram is resisted; and

(g) concluding that (i) a second syringe is present in the second syringe chamber if the movement of the second ram is resisted by a second predetermined amount of pressure or more or (ii) no syringe is present in the second syringe chamber if the movement of the second ram is resisted by less than the second predetermined amount of pressure.

13. The method of claim 9, wherein measuring how much the movement of the first ram is resisted includes measuring current supplied to a motor that drives the movement of the first ram.

14. The method of claim 9, wherein the first injector operation condition is selected from a group consisting of: a first syringe being present in the first syringe chamber, a syringe sleeve of the first syringe chamber being not closed properly for operation, a wiper of the first syringe being misaligned with a barrel of the first syringe, an occlusion within the syringe, and overpressure during injection.

15. An injection system comprising:

(a) an injector that includes a first syringe chamber and a first ram; and

(b) an injector control system that includes a processor and a storage device, wherein the storage device comprises: (i) a ram motion data module that, when executed by the processor, causes the processor to collect a first set of ram motion information regarding movement of the first ram in the first syringe chamber;

(ii) a resistance detection module that, when executed by the processor, causes the processor to collect a first set of resistance information indicating how much the movement of the first ram is resisted; and

(iii) an operation condition detection module that, when executed by the processor, causes the processor to (A) receive the first set of ram motion information from the ram motion data module, (B) receive the first set of resistance information from the resistance detection module, and (C) determine whether a first injector operation condition is present based on the first set of ram advancement information and the first set of resistance information.

16. The injection system of claim 15, wherein the operation condition detection module, when executed by the processor, causes the processor to determine whether a first syringe is present in the first syringe chamber by concluding that:

a first syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram is resisted by a predetermined amount of pressure or more or

no syringe is present in the first syringe chamber if the first set of resistance information indicates that the movement of the first ram is resisted by less than the predetermined amount of pressure.

17. The injection system of claim 16, wherein the storage device further comprises (iv) an inject process module that, when executed by the processor, causes the processor to automatically begin a syringe-fill process if it is determined that the first syringe is present in the first syringe chamber.

18. The injection system of claim 15, wherein:

the injector further includes a motor configured to drive the first ram, and

the first set of resistance information includes how much current is required by the motor to drive the first ram.

19. The injection system of claim 15, wherein the first injector operation condition is selected from a group consisting of: a first syringe being present in the first syringe chamber, a syringe sleeve of the first syringe chamber being not closed properly for operation, a wiper of the first syringe being misaligned with a barrel of the first syringe, an occlusion within the syringe, and overpressure during injection.

20. The injection system of claim 15, wherein the first set of ram motion information includes one or more of:

a location of the first ram relative to a reference point,

a duration of time that the first ram has been moving, and

a rate at which the first ram is moving or accelerating.