ANGIOGRAPHIC INJECTOR EQUIPMENT

• US 3,701,345 A
• Filed: 09/29/1970
• Issued: 10/31/1972
• Est. Priority Date: 09/29/1970
• Status: Expired due to Term

• Current Assignee: Donald Jones, Marlin S. Heilman, Rudolph J. Kranys
• Original Assignee: Donald Jones, Marlin S. Heilman, Rudolph J. Kranys
• Inventors: Heilman, Marlin S., Kranys, Rudolph J., Jones, Donald
• Primary Examiner(s): Truluck, Dalton L.
• Application Number:
  US05/076,491
• Time in Patent Office: 763 Days
• Field of Search: 128/2R,2A,2.5F,2.5R,215,218R,218A,DIG.1
• US Class Current: 600/432
• CPC Class Codes: A61B 6/481 involving the use of contrast agents
• CPC Class Codes: A61B 6/504 for diagnosis of blood vessels, e.g. by angiography
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: B01L 3/0227 Details of motor drive means B01L3/0231, B01L3/0234 take precedence
• CPC Class Codes: G05D 7/0676 by action on flow sources G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10S 128/01 Motorized syringe

Abstract

An angiographic injector control system for delivering a controlled volume of injection fluid is described. The injector has a motor driven piston for ejecting fluid from a syringe cartridge contained within a pressure jacket. The drive motor is operated in accordance with a command voltage corresponding to an incremental position of the injector piston, the command position signal also corresponding to the volume of fluid to be ejected from the cartridge. This command position voltage signal is compared to an actual position voltage to produce an error signal for operating the drive motor, whereby the syringe piston follows the position command signal. Volume selector means produce a volume signal corresponding to a desired maximum volume of fluid to be ejected; this volume signal is compared to the sum of the position command increments, producing a stop signal when the position command signal equals or exceeds the volume limit signal. Thus, the injector control system regulates the injection of fluid by sensing and controlling the position of the injector piston.

Claims

1. An injection system for producing a controlled volume of injection fluid for use in angiography comprising:

a. an injector including syringe means for said fluid, piston means connected to said syringe and movable along a linear path for ejecting said fluid from said syringe means, conduit means for connecting said syringe means to a patient, and a drive motor for moving said piston; and

b. control means for said injector, said control means including command means for producing a command signal which is a function of the desired injector piston position, sensing means for producing a position signal which is a function of the actual injector piston position along its path, and means for comparing said command and actual position signals to produce a resultant signal for operating said drive motor, whereby said piston is advanced along said path to its command position to eject said controlled volume of fluid.

2. The injector system of claim 1 wherein said sensing means is a potentiometer driven by said injector to produce said position signal.

3. The injector system of claim 2 wherein said control means further includes means for selecting the volume of fluid to be injected by said injector, and means for regulating the operation of said drive motor to terminate an injection after said selected volume has been injected.

4. The injector system of claim 3 wherein said means for regulating the operation of said drive motor includes a comparison means responsive to a first signal corresponding to the selected volume and to said position signal, said position signal corresponding to incremental movement of said drive motor, said comparison means producing an output when the position signal is equal to or greater than said first signal. 5. The injector system of claim 4 wherein said control means further includes a disarm circuit for said injector, the output from said comparison means being effective to trigger said disarm circuit and stop said drive motor.

6. The injector system of claim 1 wherein said command means includes means for selecting a predetermined command function, and integrator means for integrating said command function to produce said command signal.

7. The injector system of claim 1 wherein said control means further includes means for selecting a maximum injector pressure in said syringe and means for regulating the operation of said drive motor to limit said injector pressure to the selected value.

8. The injector system of claim 7 wherein said means for limiting said injector pressure includes means for producing a signal proportional to the actual torque of said drive motor, comparing said torque signal to a signal proportional to said selected injector pressure and producing a resultant pressure limit signal for regulating said drive motor.

9. The injection system of claim 8 wherein said means for producing a signal proportional to the actual torque of said drive motor comprises a resistor in series with said motor.

10. The injector system of claim 8 wherein said means for selecting a maximum injector pressure further includes actual means responsive to said signal proportional to the actual torque of said drive motor for displaying the torque in terms of injector pressure.

11. The injector system of claim 5, further including fault detector means responsive to malfunctions in said injector for triggering said disarm circuit to stop said drive motor.

12. The injector system of claim 1, wherein said resultant signal for operating said drive motor is an error signal proportional to the difference between the instantaneous value of said command signal and the incremental position of the injector piston, the instantaneous value of said position signal being proportional to said incremental position.

13. The injector system of claim 1, further including means for producing a volume selector signal which may be varied to select a desired displacement of said piston, means responsive to said actual position signal for establishing a signal proportional to the initial location of said piston, and means for comparing said initial location signal, actual position signal and volume selector signal and for producing a volume limiting signal when the difference between said initial location signal and said actual position signal equals said volume selector signal, said volume limiting signal terminating an injection after said selected volume has been injected.

14. The injector system of claim 13 wherein said means for establishing said signal proportional to the initial location of said piston comprises a memory circuit for storing the position signal at the start of an injection.

15. The injector system of claim 14, wherein said means for producing a volume selector signal comprises a digital switch array.

16. The injector system of claim 1 wherein said control means further includes an arm/disarm circuit for said injector drive motor, said arm/disarm circuit being operable to establish and to interrupt the armature current of said motor.

17. The injector system of claim 16 wherein said control circuit further includes means for generating a volume limit signal, and means within said arm/disarm circuit responsive to said volume limit signal for terminating the operation of said injector after a predetermined amount of fluid has been ejected from said syringe means.

18. The injector system of claim 1, wherein said control circuit further includes pressure limit means for limiting the armature current of said motor.

19. The injector system of claim 18, said pressure limit means comprising means for producing an actual pressure signal proportional to the actual armature current in said motor, pressure selector means for producing a selected pressure sigNal proportional to the desired maximum armature current, and comparator means for producing a pressure limit signal proportional to the difference between said actual pressure signal and said selected pressure signal, said pressure limit signal modifying said resultant signal for regulating the operation of said drive motor.

20. The injector system of claim 17 wherein said means within said arm/disarm circuit responsive to said volume limit signals comprises a volume limit switch, said volume limit switch serving to terminate the operation of said injector and permitting subsequent injection cycles in a multiple inject mode.

21. The injector system of claim 17 wherein said means within said arm/disarm circuit responsive to said volume limit signals comprises a disarm switch to terminate the operation of said injector and preventing subsequent injection cycles to thereby establish a single inject mode.

22. The injector system of claim 21 wherein said arm/disarm circuit further includes an arm switch, a master relay, and a volume limit switch in series with said disarm switch and with a start switch, closure of all said arm/disarm circuit switches and consequent energization of said master relay being required for operation of said injector.

23. The injector system of claim 22 wherein said arm/disarm switch further includes a safe circuit in series with the armature of said drive motor, said safe circuit being controlled by said master relay, whereby said arm/disarm circuit regulates the operation of said drive motor.

24. The injector system of claim 22, further including fault detector means responsive to malfunctions in said injector for opening said disarm switch, thereby to disable said drive motor.

25. The injector system of claim 24, wherein said fault detector means includes overrate sensing means responsive to the speed of said drive motor, said overrate sensing means producing a fault output for disabling said motor when said motor exceeds a predetermined speed.

26. The injector system of claim 1 wherein said means for producing a command signal comprises a digital switch array having adjustable switch contacts for selecting a desired command signal level.

27. The injector system of claim 1, wherein said means for producing a command signal comprises a source of variable voltage, whereby said command signal varies in accordance with a preselected program to produce a desired command signal function.

28. The injector system of claim 27, wherein said source of variable voltage comprises an array of potentiometers connectable to a common line, and means for sequentially connecting said potentiometers to said line, whereby said variable voltage is a step function corresponding to the settings of said potentiometers.

29. The injector system of claim 28 wherein said means for sequentially connecting said potentiometers to said common line comprises clock-driven counter means having a plurality of outputs, each output being energized in sequence to connect a corresponding potentiometer to said common line.

30. The injector system of claim 29, further including means for synchronizing said counter means with an electrocardiogram, whereby said command signal function is initiated at a selected time.

31. The injector system of claim 30, further including counter means for counting the number of times said command signal function is generated, said counter means producing an output signal after a predetermined count is reached to terminate operation of said drive motor.

32. The injector system of claim 1, further including fault detector means responsive to malfunction in said injector for stopping said drive motor.

33. The injector system of claim 32, wherein said fault detector means includes overrate sensing means responsive to the speed of said drive motor, said overrate sensing means producing a fault output for disabling said drive motor when said drive motor exceeds a predetermined speed.