JP2011234774A - Medical fluid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the undesirable mixing of a medical fluid or the inaccurate injection of the medical fluid without using a brake.SOLUTION: The medical fluid injection device 100 includes a plurality of piston driving mechanisms 130 independently driven in order to advance the pistons of a plurality of syringe assemblies and a control part 161 for controlling the operation of the piston driving mechanisms 130. The piston driving mechanisms 130 have piston holding mechanisms for pressing the pistons in an advance direction by the driving of drive motors 134 and rotation detectors 135 for detecting the rotation of the drive motors 134. The control part 161 has a retreat determining part 161a for determining whether the piston holding mechanism retreats on the basis of the output from the rotation detector 135 with respect to the non-driven piston driving mechanism 130 and rotating the drive motor 134 in a case that the piston holding mechanism is determined to retreat so as to advance the piston holding mechanism by the retreat quantity.

Description

  The present invention relates to a chemical solution injection device for injecting a chemical solution filled in a syringe into a subject.

  Medical diagnostic imaging apparatuses include a CT (Computed Tomography) scanner, an MRI (Magnetic Resonance Imaging) apparatus, a PET (Positron Emission Tomography) apparatus, an angiographic apparatus, and an MRA (MR Angio) apparatus. When taking fluoroscopic images of a subject using these devices, a chemical solution such as a contrast medium or physiological saline is often injected into the subject.

  In general, injection of a chemical solution into a subject is automatically performed using a chemical solution injection device. The chemical injection device has an injection head to which a syringe is detachably attached and an injection control unit for controlling the operation of the injection head. The syringe has a cylinder and a piston inserted into the cylinder so as to be capable of moving forward and backward, and the liquid medicine is filled in the cylinder.

  The injection head includes a syringe fixing mechanism that detachably fixes the syringe, and a piston drive mechanism that moves the piston while the cylinder is fixed to the injection head. The injection needle or catheter is connected to the tip of the cylinder via an extension tube, and the injection needle or catheter is punctured or inserted into the blood vessel of the subject, and then the piston is pushed into the cylinder by the piston drive mechanism to fill the syringe. The medicinal solution can be injected into the subject.

  In the injection of a drug solution, for example, the tube and / or catheter is flushed with physiological saline in order to prevent coagulation of blood that has flowed back into the tube and / or catheter after injection of a contrast medium. In some cases, the contrast medium is injected while being diluted with physiological saline, or the physiological saline is injected after the contrast medium is injected, and the contrast medium is boosted by the physiological saline. Thus, some chemical liquid injectors are equipped with a plurality of syringes so that a plurality of types of chemical liquids can be injected by a single chemical liquid injector.

  When a plurality of syringes are mounted on a chemical solution injector equipped with a plurality of syringes to inject a plurality of types of chemical solutions, a tube unit is used in which the end side branches into a plurality of branches and each branched branch is connected to each syringe. For this reason, when a high-viscosity contrast medium is injected from one syringe, the pressure is transmitted to the other syringe through the tube, causing the piston to retreat, thereby causing the contrast medium to be sucked into the other syringe.

  Therefore, in Patent Document 1, in a chemical liquid injection device in which a plurality of syringes can be mounted, when the chemical liquid is injected from at least one syringe and the injection of the chemical liquid from the remaining syringes is stopped, the injection is stopped. As for the piston drive mechanism of the syringe, a chemical injection device is disclosed in which the backward movement is prohibited by a braking device such as an electromagnetic brake, a disc brake, or a ratchet mechanism. According to this chemical solution injection device, it is possible to prevent undesirable mixing of the chemical solution and inaccurate injection amount.

  Moreover, in the chemical injection device that does not include such a braking device, the one-valve tube is attached to the syringe, and the tip of the one-valve tube is connected to the tube or the catheter, so that the chemical solution is syringed from the tube side. It is also done to prevent backflow.

JP 2002-102343 A

  However, in the chemical solution injection device disclosed in Patent Document 1, in order to inject a chemical solution that is often injected at a high injection pressure, such as a contrast agent, the injection pressure transmitted to other syringes during the injection of the chemical solution is also relatively high, The braking device needs to generate enough force to counter the high pressure. A braking device capable of generating a large force is usually large and heavy. Therefore, the piston drive mechanism will increase the weight of the injection head by the amount of the braking device, and depending on the weight of the braking device, handling of the injection head when moving the injection head or changing the posture of the injection head May be reduced. In particular, the electromagnetic brake is heavy and has a great influence on the handling of the injection head. In addition, having a braking device leads to an increase in the cost of the chemical liquid injector.

  On the other hand, when using a valved tube to prevent the chemical liquid from flowing into the syringe, the above-mentioned problem does not occur because a braking device is unnecessary. However, when injecting a drug solution, the piston is retracted after insertion of the injection needle or catheter in order to confirm the insertion position, which is confirmation of whether the injection needle or catheter is inserted into the blood vessel of the subject. It is often the case that blood is intentionally refluxed. However, in the state where the one-way valved tube is connected to the syringe, the blood cannot flow backward.

  Therefore, conventionally, a small-capacity syringe connected with a normal tube that is not a one-way tube is prepared separately from the injection of the chemical solution, and the normal tube connected to this small-capacity syringe is used as the injection needle. The insertion position was confirmed by connecting to an infusion tube or a catheter to which was connected. Then, after confirming the insertion position, remove the small-capacity syringe from the normal tube, and then connect the one-valve tube connected with the air and vent the syringe. A small volume syringe for confirmation was connected to the tube from which it was removed to inject the chemical solution. As described above, when the one-valve tube is used, the syringe must be replaced when the insertion position is confirmed. As a result, it takes much time to prepare for the injection of the chemical solution, and also causes a mistake in mounting the syringe and a connection error in the tube.

  An object of this invention is to provide the chemical | medical solution injection | pouring apparatus which can prevent that an unpreferable mixing of chemical | medical solution and an injection amount become inaccurate, without using a brake device or a tube with one valve.

  The chemical injection device of the present invention is equipped with a plurality of syringes, each of which is equipped with a plurality of syringes each having a cylinder and a piston, and injects a chemical solution in the syringe by advancing the pistons of the syringes attached. A plurality of piston drive mechanisms that are driven independently of each other to advance the piston of the syringe, and a control unit that controls the operation of the piston drive mechanism. Each of the piston drive mechanisms includes a piston pressing member supported so as to be able to advance and retract so that the piston can be advanced by an advance operation, a drive motor rotated to advance and retract the piston pressing member, and a drive A rotation detector for detecting rotation of the motor. The control unit determines whether the piston pressing member is retracted based on the output from the rotation detector for the piston drive mechanism that is not driven among the plurality of piston drive mechanisms, and determines that the piston is retracted. The retraction determination unit rotates the drive motor so that the piston pressing member is advanced by the retreated amount.

  In the above chemical injection device of the present invention, when the control unit switches from the forward movement of the piston by the at least one piston drive mechanism to the forward movement of the piston by the remaining at least one piston drive mechanism, In order to prevent the stable operation state and the stable operation state of the remaining at least one piston drive mechanism from overlapping in time, a predetermined time difference is given before or after the drive of the at least one piston drive mechanism is stopped to provide at least the remaining one It is preferable to further include a time difference drive unit that starts driving of the two piston drive mechanisms.

  The drive motor is preferably a direct current brushless motor. In this case, the DC brushless motor preferably includes a rotor provided with a plurality of magnets and a magnetic sensor for detecting the positions of the plurality of rotors, and uses the magnetic sensor as a rotation detector.

  Alternatively, the rotation detector can be a rotary encoder.

  According to the present invention, it is possible to prevent the chemical solution from flowing into another syringe during the injection of the chemical solution by using only the operation control of the drive motor without using the braking device by having the reverse determination unit. . As a result, while reducing the weight of the chemical liquid injector, it is possible to prevent undesirable mixing of the chemical liquid and inaccurate injection amount.

1 is a perspective view of a fluoroscopic imaging system according to an embodiment of the present invention. It is a perspective view of the chemical injection device shown in FIG. It is a perspective view which shows the injection | pouring head shown in FIG. 2 with the syringe with which it is mounted | worn. It is a side view of the piston drive mechanism built in the injection head shown in FIG. It is a block diagram which shows the electrical structure of a chemical injection device.

  Referring to FIG. 1, there is shown a fluoroscopic imaging system 1000 according to an embodiment of the present invention having an X-ray CT apparatus 300 that is a fluoroscopic imaging apparatus and a chemical solution injection system. The chemical solution injection system includes a chemical solution injection device 100 and a syringe assembly 200 (see FIG. 3) attached to the chemical solution injection device 100. The X-ray CT apparatus 300 includes an imaging unit 301 that performs an imaging operation, and an imaging control unit 302 that controls the operation of the imaging unit 301, and these are connected via a communication network.

  For example, as shown in FIG. 2, the chemical liquid injector 100 includes an injection head 110 that is pivotably attached to an upper portion of a stand 111, and an injection control unit 101 that is electrically connected to the injection head 110 via a cable 102. is doing. The injection control unit 101 has a main operation panel 103 and a touch panel 104 that serves as both display means and input means. The injection control unit 101 may further include a hand unit (not shown) as auxiliary input means electrically connected to the main body of the injection control unit 101 with a cable (not shown).

  As shown in FIG. 3, the injection head 110 detachably mounts two syringes 200C and 200P in parallel. The syringes 200 </ b> C and 200 </ b> P have a cylinder 221 having a cylinder flange 221 a formed at the end and a nozzle portion 221 b formed at the tip, and a piston 222 inserted into the cylinder 221 so as to be capable of moving forward and backward.

  As the piston 222 moves forward toward the tip of the cylinder 221, the filled chemical liquid is pushed out from the syringes 200C and 200P through the nozzle portion 221b. To the nozzle part 221b of each syringe 200C, 200P, two end parts of an extension tube 230 having an injection needle or a catheter connected to the tip and bifurcated in the middle are connected. Thereby, an injection needle or a catheter can be punctured or inserted into the blood vessel of the subject, and the liquid medicine filled in the syringes 200C and 200P can be injected into the subject. Examples of the chemical solution filled in the syringes 200C and 200P include contrast agents, physiological saline, and anticancer agents. For example, one syringe 200C is filled with a contrast agent, and the other syringe 200P is filled with physiological saline. Can be filled. Alternatively, both of the syringes 200C and 200P can be filled with an anticancer agent.

  In a chemical solution injection system, a chemical solution having a high viscosity is often used like the above contrast agent. When injecting a high-viscosity chemical solution, a high injection pressure is required. In addition, a high injection pressure is required when injecting a drug solution using an elongated catheter.

  The tip of the injection head 110 is provided with a syringe receiver 120 that constitutes a syringe mounting part on which two syringes 200C and 200P are placed. The syringe receiver 120 has two recesses 120 a formed to receive the outer peripheral surface of the cylinder 221. In addition, syringe adapters 121 and 122 holding the cylinder flanges 221a of the syringes 200C and 200P are detachably attached to the syringe receiver 120.

  The syringes 200C and 200P placed on the syringe receiver 120 are fixed to the injection head 110 by positioning the cylinder 221 in the recess 121 with the nozzle portion 221b facing the tip side and holding the cylinder flange 221a. It is installed in the state. However, there are various sizes and / or shapes of the syringes 200C and 200P, and it is difficult to hold the cylinder flanges 221a of all types of syringes 200C and 200P with a common holding structure. Therefore, in this embodiment, for each shape of the syringes 200C and 200P to be mounted, a plurality of types of syringe adapters each having a holding structure suitable for holding the cylinder flange 221a and detachably mounted on the syringe receiver 120. 121 and 122 are prepared, and the syringe adapters 121 and 122 to be used are exchanged according to the types of the syringes 200C and 200P, so that various sizes and / or syringes 200C and 200P can be attached to the injection head 110. .

  The injection head 110 is equipped with two piston drive mechanisms 130 that are driven independently of each other to advance / retract the pistons 222 of the attached syringes 200C, 200P separately or simultaneously, and each syringe 200C, 200P is attached. It is provided corresponding to the position. Hereinafter, the piston drive mechanism 130 will be described with reference to FIG.

  The piston drive mechanism 130 includes a drive motor 134, a motion conversion mechanism that converts the rotational output of the drive motor 134 into a linear motion, and a piston holding mechanism 133 that holds the end of the piston 222 (see FIG. 3) in a freely detachable manner. Have The drive motor 134 and the motion conversion mechanism are supported by the frame 111 of the injection head 110 (see FIG. 3).

  The motion conversion mechanism is engaged with the ball screw 131 supported on the frame 111 so as to be rotatable and immovable in the axial direction, and is linearly moved along the ball screw 131 as the ball screw 131 rotates. And a ball nut unit 132. The piston holding mechanism 133 constitutes a piston pressing member in the present invention, and can be moved forward and backward so that the piston 222 can be pressed by a forward movement, via a rod at the tip of the ball nut unit 132. It is supported. The piston 222 can be held by the piston holding mechanism 133 by a known means that can be normally used in this type of apparatus. Here, the piston holding mechanism 133 that holds the piston 222 is shown as the piston pressing member. However, the piston pressing member may be configured to press at least the piston 222 in the forward direction.

  An output shaft of the drive motor 134 is connected to the ball screw 131. Although the ball screw 131 can be directly connected to the output shaft of the drive motor 134, in this embodiment, it is connected via a power transmission mechanism. The power transmission mechanism includes a pulley 136b fixed to the output shaft of the drive motor 134, a pulley 136a fixed to the end of the ball screw 131, and a belt 137 wound around the two pulleys 136a and 136b. As a power transmission mechanism, a gear device can be used instead of such a belt transmission mechanism.

  In the piston drive mechanism 130 configured as described above, when the drive motor 134 is driven, the rotation is transmitted to the ball screw 131 via the power transmission mechanism, whereby the ball screw 131 corresponds to the rotation direction of the drive motor 134. Rotate in the forward or reverse direction. When the ball screw 131 rotates, the ball nut unit 132 moves forward or backward along the ball screw 131 according to the rotation direction.

  Accordingly, if the drive motor 134 is driven in a state where the piston 222 is held by the piston holding mechanism 133 attached to the ball nut unit 132 via a rod, the syringes 200C and 200P attached to the injection head 110 (see FIG. 3). ) Piston 222 can be moved relative to cylinder 221.

  FIG. 5 shows a block diagram of the main electrical configuration of the chemical liquid injector of this embodiment. Each block shown in FIG. 5 exists as at least a part of the configuration described in FIGS. 1 to 4 or a combination of at least a part thereof, and may be configured as hardware or configured as a logic circuit. May be.

  As shown in FIG. 5, the drive motor 134 has a rotation detector 135 that detects the rotation of the rotor or the output shaft. The rotation detector 135 may be, for example, a rotary encoder, and a servo motor can be used as the drive motor 134 having such a rotation detector 135. As the drive motor 134, either an AC motor or a DC motor can be used according to the power source to be used. In the chemical liquid injector 100, a DC motor is generally used.

  Further, there are brush motors and brushless motors as motor types, and any of them can be used as the drive motor 134. In the present invention, in particular, a DC brushless motor is preferably used as the drive motor 134. Can do. A brushless motor has the advantage that it is quiet and excellent in durability due to the absence of a brush. In addition, since the brushless motor can rotate at a higher speed, if the external gear ratio is increased to reduce the torque applied to the motor, the current value necessary for injecting the chemical solution at a desired injection pressure is supplied to the brush motor. It can be made smaller. As a result, a thinner cable can be used, and thus the weight of the injection head 110 can be reduced.

  Furthermore, a brushless motor generally has a rotor in which a plurality of magnets are arranged in the circumferential direction, and a magnetic sensor such as a hall sensor for detecting the positions of these magnets. Therefore, if this magnetic sensor is used as the rotation detector 135, a rotary encoder is unnecessary. Further, the rotation amount and rotation speed of the motor can be known using the output from the magnetic sensor. Since the rotation amount and rotation speed of the motor correspond to the position and movement speed of the piston holding mechanism 133, as a result, the injection amount, injection speed, remaining amount, etc. of the chemical solution are detected using the magnetic sensor in the motor. Can do. Thereby, the injection head 110 does not require a sensor for detecting the injection amount of the chemical solution, and the configuration of the injection head 110 can be simplified.

  On the other hand, the injection control unit 101 includes a control unit 161, an input unit 162, a display unit 163, and an interface (I / F) 164.

  The input unit 162 corresponds to the main operation panel 103 and the touch panel 104 shown in FIG. 2 and accepts input of data necessary for determining various settings of the chemical liquid injector 100 and chemical injection conditions by the operator. The display unit 163 corresponds to the touch panel 104 shown in FIG. 2, and displays a screen representing the operating state of the chemical solution injector 100 and a data input screen. As described above, in this embodiment, the touch panel 104 has both a function as a part of the input unit 162 and a function of the display unit 163.

  The control unit 161 calculates the injection condition of the chemical solution based on the input from the input unit 162, displays necessary information on the display unit 163, and inputs or calculated the injection time, the injection amount, the injection speed, and the like. The overall operation of the chemical injection device 100 is controlled, for example, by controlling the operation of the piston drive mechanism 130 in accordance with a predetermined injection procedure and a predetermined procedure.

  In the present invention, the control unit 161 includes a backward determination unit 161a and a time difference driving unit 161b in addition to the above functions. The reverse determination unit 161a is in a stopped state without a control signal being issued to advance or retreat the piston drive mechanism 130 that is not driven, in other words, the piston holding mechanism 133 (see FIG. 4). , It is determined whether the piston holding mechanism 133 (see FIG. 4) is retracted based on the output from the rotation detector 135 provided therein. The drive motor 134 is rotated so as to advance the piston holding mechanism 133 by the amount. In order to inject the other chemical liquid continuously after injecting one chemical liquid, the time difference driving section 161b advances from the forward movement of the piston 222 by one piston drive mechanism 130 to the forward movement of the piston drive mechanism 222 by the other piston drive mechanism 130. When switching to operation, after driving of one piston drive mechanism 130 is stopped, the other piston drive mechanism 130 is driven with a predetermined time difference. The control unit 161 can be configured by a computer unit including a CPU, a RAM, and a ROM, and the retreat determination unit 161a is included in the control unit 161 as one of the functions.

  An operation start signal of the piston drive mechanism 130 issued from the control unit 161, a part of the injection condition of the chemical solution calculated by the control unit 161, and the like are sent to the X-ray CT apparatus 300 via the interface 164. The chemical injection device 100 and the X-ray CT apparatus 300 can be interlocked.

  Next, the operation of the chemical liquid injector 100 of this embodiment will be described.

  First, the operator attaches to the injection head 110 syringes 200C and 200P filled with a chemical to be injected into the subject. Alternatively, after attaching empty syringes 200C and 200P that are not filled with a chemical solution to the injection head 110, predetermined chemical solution containers (not shown) are connected to the syringes 200C and 200P, respectively, by an appropriate method conventionally used. In this state, the syringes 200C and 200P filled with the chemical solution may be mounted on the injection head by separately retracting the pistons 222 of the syringes 200C and 200P and filling the syringe assembly 200 with a predetermined chemical solution. Good.

  As described above, the types of the syringe 200 viewed from the filling state of the chemical liquid include a syringe pre-filled with the chemical liquid (prefilled syringe) and a syringe filled with the chemical liquid in the field as described above. Either can be used. In the case of a prefilled syringe, an injection needle or a catheter is connected to the syringes 200C and 200P via the extension tube 230 before or after the syringes 200C and 200P are attached to the injection head 110.

  Furthermore, a syringe equipped with an RFID tag that records various data can also be used in the present invention. In this case, the injection head 110 includes a reader / writer that reads data from the RFID tag in a state where the syringe assembly 200 is mounted. When the syringe assembly 200 is mounted, the data recorded in the RFID tag is read. It is preferable to be configured so that data can be rewritten.

  When the operator confirms that the syringes 200C and 200P are attached to the injection head and that the injection needle or the catheter is connected to the serial 200C and 200P via the extension tube 230, a predetermined input means that the confirmation has been made. The operation is performed by the input unit 162.

  When this input operation is performed, the control unit 161 performs an initialization operation of the piston drive mechanism 130. In the initialization operation, both piston drive mechanisms 130 are driven to advance the piston holding mechanism 133, and the pistons 222 of the syringes 200C and 200P are held by the piston holding mechanism 133.

  After the initialization operation of the piston drive mechanism 130, the control unit 161 releases the air from the extension tube 230 and the like according to a predetermined operation by the operator. In the air bleeding, both the piston drive mechanism 130 is driven simultaneously to further advance the piston holding mechanism 133 and push out the chemical solution in the syringes 200C and 200P, thereby connecting to the extension tube 230 connected to the syringes 200C and 200P. Fill the injected needle or catheter with the drug solution. In this way, both the piston drive mechanisms 130 are driven at the same time to simultaneously release the air from both syringes 200C and 200P, thereby preventing the air pushed out from one syringe side from flowing into the other syringe side. can do. Since the amount of movement of the piston holding mechanism 133 necessary for air venting varies depending on the length of the extension tube 230, the amount of movement of the piston holding mechanism 133 for air venting is arbitrarily set in order to prevent wasteful use of the chemical solution It is preferable to be able to do this.

  In order to be able to confirm whether or not air has been reliably removed by this air venting, the chemical liquid injector is preferably provided with a bubble sensor (not shown) that detects bubbles present in the extension tube 230 and the like. As the bubble sensor, a known sensor that can be used for detecting bubbles in the tube, such as an ultrasonic sensor, an optical sensor, and a capacitive sensor, can be used. Detection of bubbles by the bubble sensor can be performed not only during air bleeding but also during the injection of the chemical solution. By using the bubble sensor, when a bubble is detected, an alarm is given to the operator with a lamp or sound, or the operation of the piston drive mechanism 130 is stopped, and the liquid medicine mixed with the bubble is injected into the subject. Can be prevented.

  In the case of a system in which the syringe 200C, 200P is filled with the chemical solution from the chemical solution container as described above and the filled chemical solution is injected into the subject, a liquid level sensor (not shown) for detecting the liquid level position in the chemical solution container is installed. It is also preferable that the presence or absence of a chemical solution in the chemical solution container can be detected. Also in this case, it is possible to prevent air from being sucked into the syringes 200C and 200P by issuing an alarm to the operator based on the detection result by the liquid level sensor or stopping the filling operation of the chemical liquid. .

  After completing the air bleeding, the operator punctures or inserts an injection needle or catheter connected to the tip of the extension tube 230 into the blood vessel of the subject. Thus, preparations for injecting the chemical solution filled in the syringes 200C and 200P into the subject are completed.

  On the other hand, the control unit 161 causes the display unit 163 to display an operation mode selection screen and / or an injection condition setting screen of the chemical solution injection device 100 and also allows the input unit 162 to select and / or inject an operation mode. Allows input operations to set conditions.

  When an operation mode selection screen and / or an injection condition setting screen are displayed on the display unit 163, the operator selects an operation mode or inputs data as necessary. Based on this input, the control unit 161 performs necessary processing and controls the piston drive mechanism 130 to inject a drug solution from the syringe assembly 200 to the subject.

  Here, when a contrast medium and physiological saline are used as the chemical solution, as a procedure for injecting the chemical solution, first, the contrast agent is injected, and after the injection of the contrast agent, the physiological saline is continuously injected. May boost the contrast agent. According to this injection procedure, the amount of contrast medium injected can be reduced. Further, in order to prevent blood that has flowed back into the extension tube 230 from coagulating after the injection of the contrast agent, the inside of the extension tube 230 is flushed with physiological saline.

  As described above, when the contrast medium and the physiological saline are sequentially injected from each syringe assembly 200 in this order, in the present embodiment, the control unit 161 controls the two piston drive mechanisms 130 as follows. In the following description, in order to clarify which of the two sets of piston drive mechanisms 130 is described, each piston drive mechanism 130 and each element constituting the piston drive mechanism 130 include the last of the syringes 200C and 200P to be operated. The letters C and P will be described as subscripts. Further, it is assumed that one syringe 200C is filled with a contrast medium, and the other syringe 200P is filled with physiological saline.

  First, during injection of the contrast agent, the control unit 161 starts driving the drive motor 130C of the piston drive mechanism 130C on the contrast agent side to advance the piston holding mechanism 133C. As a result, the piston 222C is pushed into the cylinder 221C, and the contrast medium is injected from the syringe 200C into the subject through the extension tube 230 and the like. While the contrast agent is being injected, the injection pressure is transmitted to the syringe 200P filled with physiological saline through the extension tube 230, and a force for retracting the piston 222P acts on the syringe 200P. Since the piston holding mechanism 133P holds the end of the piston 222P, the force for moving the piston 222P backward acts on the piston driving mechanism 130 as the force for moving the piston holding mechanism 133P as it is.

  On the other hand, during the contrast agent injection operation, the piston drive mechanism 130P for operating the syringe 200P filled with physiological saline is not driven. That is, the control signal from the control unit 161 is not issued to the drive motor 134P, and the drive motor 134P is not driven. While the drive motor 134P is not being driven, the piston holding mechanism 133P can freely move forward and backward. Therefore, in a state where the piston drive mechanism 130P is not driven, the contrast medium injection pressure acts on the syringe 200P, so that the piston 222P is largely retracted, and the contrast medium may flow into the syringe 200P.

  As described above, when the piston 222P is retracted by the injection pressure of the contrast agent acting on the syringe 200P, the piston holding mechanism 133P is also retracted, and the movement of the piston holding mechanism 133P is performed via the ball screw mechanism and the power transmission mechanism. It is transmitted to the drive motor 134P and the drive motor 134P is rotated. The rotation of the drive motor 134P is detected by the rotation detector 135P, and a detection signal corresponding to the rotation angle of the drive motor 134P is sent from the rotation detector 135P to the reverse determination unit 161a of the control unit 161.

  When the reverse determination unit 161a receives the detection signal from the rotation detector 135P, it determines that the piston holding mechanism 133P has retracted. Further, since the rotation angle of the drive motor 134P can be known from the detection signal from the rotation detector 135P, the reverse determination unit 161a reversely rotates the drive motor 134P by the rotation angle of the drive motor 134P. As a result, the piston holding mechanism 133P moves forward by the amount retracted, and the piston 222P is pushed back by the piston holding mechanism 133P, so that the contrast agent can be prevented from flowing into the syringe 200P during the contrast agent injection operation. By preventing the inflow of the contrast medium, it is possible to prevent undesired mixing of the chemical solution and inaccurate injection amount.

  Further, since the prevention of the inflow of the contrast medium into the physiological saline syringe 200P as described above can be achieved only by controlling the operation of the drive motor 134P, the conventionally used braking device is not required, and the injection head 110 correspondingly. Can be reduced in weight. As a result, the handleability of the injection head 110 can be improved.

  The determination of the retraction of the piston holding mechanism 133P by the retraction determination unit 161a can be performed all the time or can be performed at regular time intervals. When the determination is always performed, the drive motor 134P can be controlled in units of the minimum rotation angle of the drive motor 134P, and the inflow of the contrast medium to the syringe 200P can be more reliably prevented.

  When the advance distance of the piston holding mechanism 133C driven by the drive motor 134C reaches a predetermined distance corresponding to the scheduled contrast agent injection amount, the control unit 161 sets the drive motor 134C of the contrast agent piston drive mechanism 130C. Stop driving. Before and after that, the controller 161 starts driving the drive motor 134P to advance the piston holding mechanism 133P in order to switch the chemical solution to be injected. As a result, physiological saline is subsequently injected after the contrast agent is injected.

  At this time, when the control unit 161 switches from the advance of the piston 222C by the contrast medium piston drive mechanism 130C to the advance of the piston 222P by the physiological saline piston drive mechanism 130P, the time difference drive means 161b causes the piston drive mechanism 130P to move forward. The drive timing is delayed by a predetermined time after the piston drive mechanism 130C is stopped, and after the predetermined time has elapsed, the drive motor 134P of the piston drive mechanism 130P for physiological saline is driven to advance the piston 222P.

  When the contrast medium is injected at a high injection pressure, the internal pressure of the syringe 200C is extremely high while the contrast medium is being injected, and the high internal pressure does not immediately return to the original state even when the forward movement of the piston 222C is stopped. Exist as residual pressure. The residual pressure also acts on the physiological saline syringe 200 </ b> P via the extension tube 230. While the contrast medium is being injected, since the piston 222P cannot be substantially retracted by the control of the drive motor 135P by the retreat determination unit 161a described above, the internal pressure of the syringe 200P is also high due to the injection of the contrast medium. . The internal pressure of the syringe 200P does not immediately return to the original even when the piston 222C stops moving forward, and exists as a residual pressure.

  In this state, when the injection of the contrast medium is completed and the physiological saline drive motor 134P is driven to advance the piston 222P, the residual pressure generated by the injection of the contrast medium is applied to the syringes 200C and 200P. In addition, since pressure due to the injection of physiological saline is further applied, the internal pressures of the syringe assemblies 200C and 200P increase remarkably and rapidly.

  The increased internal pressure of the syringe assemblies 200C and 200P is reduced by the contrast medium and physiological saline flowing out of the syringe assemblies 200C and 200P through the extension tube due to the internal pressure.

  Therefore, by delaying the drive timing of the physiological saline piston drive mechanism 130P as described above, the residual pressure of the syringes 200C and 200P can be lowered during that time. Thereby, the rapid increase of the internal pressure of the syringes 200C and 200P can be prevented, and the syringe 200C and 200P can be prevented from being damaged by the increased internal pressure. In addition, since the piston drive mechanisms 130C and 130P are not driven until the piston drive mechanism 130P for physiological saline is driven after a predetermined time has elapsed after the injection of the contrast medium, the retreat determination unit 161a. As a result, the above-described control is performed on both piston drive mechanisms 130C and 130P. Therefore, the pistons 222C and 222P are not substantially retracted while both the piston drive mechanisms 130C and 130P are not driven.

  The predetermined time for delaying the drive of the piston drive mechanism 130P may be a time sufficient for the residual pressure to fall to such an extent that it does not cause a problem. It can be milliseconds or longer. The predetermined delay time is preferably as short as possible within a range in which continuous injection of contrast medium and physiological saline is not hindered, and can be set to, for example, 1 second or less, preferably 100 milliseconds or less.

  Further, in order to better suppress the rapid increase in internal pressure of the syringe assemblies 200C and 200P, the force acting on the piston holding mechanisms 133C and 133P is detected by the injection operation of the chemical solution, and the injection pressure of the chemical solution is based on the detection result It is also possible to control the operation of the piston drive mechanisms 130C and 130P (specifically, rotation of the drive motors 134C and 134P) so that the value does not exceed a predetermined value. In this case, the piston drive mechanisms 130C and 130P have detection means for detecting the force acting on the piston holding mechanisms 133C and 133P, and the control unit 161 operates the piston drive mechanisms 130C and 130P as described above. It has an injection pressure control part to control. The force acting on the piston holding mechanisms 133C and 133P can be obtained, for example, by detecting the value of the current flowing through the drive motors 134C and 134P. Alternatively, a load cell (not shown) may be installed in the piston holding mechanisms 133C and 133P, and the detection result by the load cell can be obtained.

  Here, the case where the physiological saline is injected after the injection of the contrast medium has been described. However, even when the contrast medium is injected after the injection of the physiological saline, the operation and the physiology of the contrast medium piston driving mechanism 130C are described in the above description. The operation is substantially the same except that the operation of the saline piston driving mechanism 130P is replaced.

  When a series of injections of the contrast medium and physiological saline is completed as described above, the lastly injected chemical solution syringe assembly 200 has an internal pressure increased by the injection as a residual pressure even after the completion of the injection. Due to this residual pressure, the liquid medicine may be further pushed out of the syringe assembly 200 and injected into the subject even after the driving of the piston drive mechanism 130 is stopped. In order to prevent this, it is preferable to drive all the piston drive mechanisms 130 so that all the pistons 222 are simultaneously retracted after the injection of all the chemicals is completed. The retreat distance of the piston 222 at this time may be a distance that reduces the residual pressure to such an extent that the chemical liquid does not flow out from the syringe assembly 200.

  The present invention has been described with the preferred embodiments. The present invention is not limited to the above-described embodiments, and various modifications can be made.

  For example, in the above-described embodiment, the time difference driving unit 161b has shown an example in which the driving of the other piston driving mechanism 130 is started after the driving of the one piston driving mechanism 130 is stopped and a predetermined time has elapsed. However, the time difference driving means 161b may start driving the other piston driving mechanism 130 before a predetermined time before stopping the driving of one piston driving mechanism 130.

  When the piston drive mechanism 130 is driven, there may be a time lag between when the operation command is issued to the drive motor 134 as a drive source and when the drive motor 134 actually reaches a predetermined rotational speed. This time varies depending on the performance of the drive motor 134. Further, in the motion conversion mechanism that converts the rotational output of the drive motor 134 into the linear motion of the piston holding mechanism 133, and in the power transmission mechanism that transmits the rotational output of the drive motor 134 to the motion conversion mechanism, play between parts and back of the gears. Due to rush or the like, there may be a time lag between the start of rotation of the drive motor 134 and the operation of the piston holding mechanism 133.

  The piston drive mechanism 130 enters a stable operation state after the elapse of these time lags. The increase in the internal pressure of the syringe assembly 200 is not so large during the period from the start of the driving of the piston drive mechanism 130 until the stable operation state is reached. Therefore, if the stable operation state of one piston drive mechanism 130 and the stable operation state of the other piston drive mechanism 130 do not overlap in time, the other piston drive mechanism 130 is stopped before the drive of one piston drive mechanism 130 stops. Even if the driving of is started, a rapid increase in the internal pressure of the syringe assembly 200 that adversely affects the piston drive mechanism 130 and the syringe assembly 200 can be suppressed. In this case, the switching time of the liquid medicine to be injected can be shortened.

  As described above, even when the driving of the other piston driving mechanism is started before the driving of the one piston driving mechanism 130 is stopped, the time difference given by the time difference driving means 161a is, for example, 1 second or less, preferably 100 milliseconds. It can be as follows.

  Moreover, although the chemical | medical solution injection device which has the two piston drive mechanisms 130 was demonstrated in embodiment mentioned above, the number of piston drive mechanisms may be three or more. In that case, the reverse determination unit determines whether or not the piston holding mechanism is retracted based on the output from the rotation detector for the piston drive mechanism that is not driven among the plurality of piston drive mechanisms. If it is determined, the drive motor is rotated so as to advance the piston holding mechanism by the amount retracted. When the time difference drive means switches from the forward movement of the piston by the at least one piston drive mechanism to the forward movement of the piston by the remaining at least one piston drive mechanism, the time difference drive means and the remaining at least one of the stable operation state of the at least one piston drive mechanism. Start driving at least one piston drive mechanism by giving a predetermined time difference before or after stopping driving of at least one piston drive mechanism so that the stable operation state of one piston drive mechanism does not overlap in time Let

  Further, in the above-described embodiment, an example is shown in which all piston drive mechanisms do not have a braking device. However, even if some piston drive mechanisms have a braking device, at least one piston drive mechanism is braked. If the apparatus is not provided, the object of the present invention can be achieved to some extent.

DESCRIPTION OF SYMBOLS 100 Chemical liquid injection device 101 Injection control unit 110 Injection head 120 Syringe receiver 130 Piston drive mechanism 131 Ball screw 132 Ball nut unit 133 Piston holding mechanism 134 Drive motor 135 Rotation detector 161 Control part 161a Retraction judgment part 161b Time difference drive part 162 Input part 163 Display unit 200C, 200P Syringe 221 Cylinder 222 Piston 300 X-ray CT apparatus

Claims (5)

In a chemical liquid injector that injects a chemical liquid in the syringe by attaching a plurality of syringes each having a cylinder and a piston, and advancing the piston of the mounted syringe,
A plurality of piston drive mechanisms that are driven independently of each other to advance the pistons of the mounted syringes;
A control unit for controlling the operation of the piston drive mechanism;
With
Each of the piston drive mechanisms includes a piston pressing member supported so as to be able to advance and retract so that the piston can be advanced by a forward operation, and a drive motor rotated to advance and retract the piston pressing member And a rotation detector for detecting the rotation of the drive motor,
The controller is
For the piston drive mechanism that is not driven among the plurality of piston drive mechanisms, based on the output from the rotation detector, it is determined whether or not the piston pressing member is retracted, A chemical solution injection device, comprising: a reverse determination unit that rotates the drive motor so as to advance the piston pressing member by an amount corresponding to the reverse direction.   When the control unit switches from the forward movement of the piston by the at least one piston drive mechanism to the forward movement of the piston by the remaining at least one piston drive mechanism, the control unit and the remaining operation state of the at least one piston drive mechanism The at least one piston drive mechanism is provided with a predetermined time difference before or after the drive of the at least one piston drive mechanism is stopped so that the stable operation state of the at least one piston drive mechanism does not overlap with time. The chemical solution injecting device according to claim 1, further comprising a time difference driving unit that starts driving.   The chemical liquid injector according to claim 1, wherein the drive motor is a direct current brushless motor. The DC brushless motor has a rotor provided with a plurality of magnets, and a magnetic sensor for detecting positions of the plurality of rotors,
The chemical solution injector according to claim 3, wherein the rotation detector is the magnetic sensor.   The chemical injection device according to claim 1, wherein the rotation detector is a rotary encoder.

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