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AbstractAbstractOur objective was to design an infusion pump that Our objective was to design an infusion pump that will be used to deliver contrast agents during a MRI will be used to deliver contrast agents during a MRI exam. Currently used is a syringe pump injector exam. Currently used is a syringe pump injector system that delivers fluids at the rates our client system that delivers fluids at the rates our client desires. However, it is limited in its sequence desires. However, it is limited in its sequence capability and saline/gadolinium capacities. Our capability and saline/gadolinium capacities. Our client would like a new pump that is more client would like a new pump that is more programmable and large enough to hold the amount programmable and large enough to hold the amount of gadolinium and saline needed for the entirety of of gadolinium and saline needed for the entirety of one study. A replacement would reduce the total one study. A replacement would reduce the total time needed to complete imaging and consequently, time needed to complete imaging and consequently, produce more accurate results. We propose a design produce more accurate results. We propose a design where the movement of a ratchet and pawl due to an where the movement of a ratchet and pawl due to an air-driven solenoid valve/linear actuator rotates a air-driven solenoid valve/linear actuator rotates a peristaltic pump to deliver fluids to the patient.peristaltic pump to deliver fluids to the patient.

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BackgroundBackground

To be used with MRI to study To be used with MRI to study cerebral hemodyanmics in stroke cerebral hemodyanmics in stroke patientspatients

Contrast agent (gadolinium) injected Contrast agent (gadolinium) injected in blood stream to create image.in blood stream to create image.

Saline used to “flush” contrast agent Saline used to “flush” contrast agent out of circulation systemout of circulation system

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Pump Currently UsedPump Currently Used

Medrad’s Spectris Medrad’s Spectris Solaris MR Injection Solaris MR Injection SystemSystem

Specifications:Specifications:– Syringe drivenSyringe driven– 0.1 mL/s – 10.0 0.1 mL/s – 10.0

mL/smL/s– 50 mL capacity 50 mL capacity

for each for each compartmentcompartment

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Problem StatementProblem Statement

Design a MRI-compatible infusion Design a MRI-compatible infusion pump that is:pump that is:– Easily programmableEasily programmable– Made of non-ferrous materialsMade of non-ferrous materials– Capable of delivering fluids at the Capable of delivering fluids at the

desired flow ratesdesired flow rates– Large enough to hold amount of Large enough to hold amount of

gadolinium and saline needed for gadolinium and saline needed for entirety of one studyentirety of one study

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MotivationMotivation

A new infusion pump will:A new infusion pump will:– Save client’s time Save client’s time

No need to constantly refill the solutions No need to constantly refill the solutions between bolus and infusionbetween bolus and infusion

– Give accurate resultsGive accurate results Patient movements are minimized with Patient movements are minimized with

less scan interruptionsless scan interruptions– Typical interruption time: ~7 min Typical interruption time: ~7 min – Eliminates image inaccuraciesEliminates image inaccuracies

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Design SpecificationsDesign Specifications The infusion pumps must:The infusion pumps must:

– Be made of a non-ferrous materialBe made of a non-ferrous material– Deliver accurate flow ratesDeliver accurate flow rates

(0.2-4 mL/s, ± 0.02 mL/s)(0.2-4 mL/s, ± 0.02 mL/s)

– Be easily sterilized Be easily sterilized – Be durable Be durable – Be Be programmableprogrammable

Sequence: saline→bolus→saline →infusion →salineSequence: saline→bolus→saline →infusion →saline Should be done quickly so interruption time is Should be done quickly so interruption time is

minimizedminimized

– Connect to containers that can hold at least 60 Connect to containers that can hold at least 60 mL of gadolinium and 180 mL of salinemL of gadolinium and 180 mL of saline

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Initial DesignsInitial Designs

Specifications:Specifications:– Peristaltic pumpPeristaltic pump– Stepping motorStepping motor

Control with LabViewControl with LabView

Problems:Problems:– Few pumps can Few pumps can

achieve 0.2 - 4 achieve 0.2 - 4 mL/secmL/sec

– Issues with shielding Issues with shielding motor and pumpmotor and pump

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Final DesignFinal Design

Proposed Proposed Mechanism Mechanism consists of:consists of:– 5-way solenoid 5-way solenoid

valvevalve– Double action Double action

linear actuator linear actuator – Ratchet and Ratchet and

pawlpawl– Peristaltic Peristaltic

pumppump

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Final Design – Role of Solenoid Final Design – Role of Solenoid ValveValve

Air is directed into the solenoid valveAir is directed into the solenoid valve2 exit tubes with a vent for each2 exit tubes with a vent for each

1. Solenoid - charged1. Solenoid - charged air from one exit tube pushes piston in air from one exit tube pushes piston in

– Air on other side of piston is pushed back through Air on other side of piston is pushed back through valve and out the ventvalve and out the vent

2. Solenoid - discharged2. Solenoid - discharged air flow redirected to other exit tube and air flow redirected to other exit tube and

pushes piston out (opposite)pushes piston out (opposite)– Air originally pushing piston in is now venting to Air originally pushing piston in is now venting to

valve and out the ventvalve and out the vent

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Final Design/Solenoid Valve Final Design/Solenoid Valve (cont.)(cont.)

On/off cycle of On/off cycle of solenoid causes solenoid causes back and forth back and forth movement of piston movement of piston within chamber.within chamber.– Same motion Same motion

translates to translates to attached attached linear linear actuator actuator (cylinder tube)(cylinder tube) Shaft attached to Shaft attached to

pawl, which drives pawl, which drives ratchetratchet

Circuit schematic of solenoid valve

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Rotational views of solenoid Rotational views of solenoid valvevalve

(a) 3D view of solenoid valve

(b) Bottom of solenoid valve

Additional Specifications-Body width – 15 mm-2 position single-Metal seal-24 V DC / 110 V AC-L plug connector with lead wire

-Also with light and surge voltage suppressor

-Operating Pressure: 0.1 - 0.7 MPa

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Final Design (cont.)Final Design (cont.)

Shaft attached to pawl, which drives Shaft attached to pawl, which drives ratchetratchet

Ratchet connected to rod that rotates Ratchet connected to rod that rotates peristaltic pumpperistaltic pump

Rotation of peristaltic pump delivers Rotation of peristaltic pump delivers fluid to patientfluid to patient

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Final Design/Cylinder TubeFinal Design/Cylinder Tube

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Final Design/Cylinder tubeFinal Design/Cylinder tube

Additional Specifications-Front nose mount-Double acting actuation-Bore size: 1.5”-Operating pressure: 8 - 250 PSI

(a) 3D view of cylinder tube (linear actuator)

(b) Side view of cylinder tube (linear actuator)

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Future WorkFuture Work

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Possible Modifications of Possible Modifications of PrototypePrototype

Develop sensors to detect and Develop sensors to detect and control amount of air at:control amount of air at:

Air sourceAir source Peristaltic pumpPeristaltic pump

Non-ferrous linear actuatorNon-ferrous linear actuator Casing for solenoid valveCasing for solenoid valve Separate casing for ratchet, pawl, Separate casing for ratchet, pawl,

linear actuator, and peristaltic pumplinear actuator, and peristaltic pump

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AcknowledgementsAcknowledgements

Prof. Frank J. FronczakProf. Frank J. Fronczak

Dept. of Mechanical EngineeringDept. of Mechanical Engineering

Prof. John G. WebsterProf. John G. Webster

Dept. of Biomedical EngineeringDept. of Biomedical Engineering

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ReferencesReferences

Fronczak, Frank. Personal Interview. April 16, 2004 Fronczak, Frank. Personal Interview. April 16, 2004

Hospod, Frank. Personal Interview. February 2, 2004.Hospod, Frank. Personal Interview. February 2, 2004.

Medrad. (2003). Spectris Solaris MR injection system.Medrad. (2003). Spectris Solaris MR injection system.Retrieved Dec. 4, 2003, from Retrieved Dec. 4, 2003, from http://www.medrad.com/systems-and-products/maghttp://www.medrad.com/systems-and-products/magnetic-resonance/spectris-solaris.htmlnetic-resonance/spectris-solaris.html

Newman, George C. Personal Interview. April 2, 2004.Newman, George C. Personal Interview. April 2, 2004.

SMC Corporation of America (2004). Retrieved April SMC Corporation of America (2004). Retrieved April 27, 2004, from http://www.smcusa.com27, 2004, from http://www.smcusa.com

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TEAM MEMBERSTEAM MEMBERS

Aman Ghotra – LeaderAman Ghotra – Leader

Can Pi – CommunicatorCan Pi – Communicator

Miguel Benson – BSACMiguel Benson – BSAC

Prakash Rao - BWIGPrakash Rao - BWIG

2020

Client

Dr. George C. Newman, MD, PhD

Frank HospodDept. of Neurology

Advisor

Prof. John G. WebsterBiomedical Engineering

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MRI

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COM

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PATI

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BLE

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INFU

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SION

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PUM

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