vi sinh, james simonelli, prof. tsu-chin tsao

BACKGROUND

ViSinh,JamesSimonelli,Prof.Tsu-ChinTsao

IwouldliketothankmyDailyLabSupervisor,JamesSimonelli, forlendingmehisknowledgeandguidingmethroughtheprojectandProfessorTsaoforallowingmetheopportunitytoresearchinhislab.IwouldalsoliketothankWilliamHerreraandtherestoftheHSSRPstaffforgivingmetheresourcestobeoncampusandgivingmethisexperience.

DepartmentofMechanicalandAerospaceEngineering,UniversityofCalifornia- LosAngeles

Analysis and Comparison of MRI-Compatible Actuators For Use in Minimally Invasive MRI

Procedures

OurgoalistoimproveonthehydrostaticactuatorandtakeadvantageoftheMRI’simagingcapabilitiesinrealtimebyreplacingtheoversizedsyringesystemwitharollingdiaphragmcylindersystem.

CurrentMRIproceduresareverytimeconsumingduetoinaccuraciesfromthephysicianhavingtorelyonastillimagetomapoutthetargetedarea.Theseerrorscanresultinmisdiagnoses.ThecurrentsolutionistocreateamachinethatdoesnotcontainferrousmetalsandworksintheMRImachinetotakeadvantageoftheMRIimagingsysteminrealtime.Thisstudyattemptstoeliminatetheseinaccuraciesbyimprovingonthehydrostaticactuator.Thefirstprototypeusedplasticsyringesformovement.Althoughtheseplasticsyringeswererobust,theywerenotsmooth.Thecurrentprototypeusesglasssyringesandwhilethesearesmooth,theyarefragileandaretoolargetobeconsideredviable.Thedevicecanbeimprovedbyusingaactuatorthatisrobust,compact,andoperateswithlowfriction.

MATERIALS AND METHODS

CONCLUSION/DISCUSSIONS ACKNOWLEDGEMENTS

BIOPSYPROCESSForabiopsy,andiseasedtissuesampleisremovedfromapatient.ThetissueisfoundbyusinganMRImachine.Astillphotoofthetissueistakenandthephysicianusesthistodeterminewheretoinserttheneedleandtakesasampleofthetissue.Estimatingwheretoplacetheneedlecreatesanareaforerror.

GOAL

RESULTS

HydrostaticActuatorPrototype

Theexperimenthasshownthattherollingdiaphragmcylindersareassmoothastheglasssyringes.Alsothefabricreinforcedrubberrollingdiaphragmcylindersystemismuchmorestiffthantheglasssyringesystem.Withmorestiffness,thereshouldbeanincreaseinhapticfeedbackfromthesystem.Thisgivesthephysiciananothersenseotherthanvisualfeedbackwhiletakingthebiopsy.Furthermoretherollingdiaphragmcylindersaremorerobustandcompactthantheglasssyringe.

RollingDiaphragmCylinderandSyringe

Actuatorsystemismountedontoopticaltable

Displacementprobeisfittedtotheoutputoftheactuator

Forcegaugemeasurestheforceappliedontothesystem

Displacementtrackermeasuresthedistancethesystemmoves

StictionExperiment

Thefabricreinforcedrubberrollingdiaphragmcylinder’ssmoothnessiscomparabletothatoftheglasssyringes.

Stictiontest

Siliconmixtureisinjectedintoamoldandallowedtocure.Nylonisaddedforfabricreinforcement.

Rubberdiaphragmfabrication

FabricReinforcedRubberDiaphragm

Non-reinforcedRubberDiaphragm

StiffnessExperiment

Actuatorsystemismountedontoopticaltable

Displacementprobeisfittedtothesystem

Outputsideofactuatorislockedfrommoving

Displacementtrackermeasuresthedistancethesystemmoves

Forcegaugemeasurestheforceappliedontothesystem

StiffnesstestThestiffnessofthefabricreinforcedrubberrollingdiaphragmcylinderismuchhigherthanthatoftheglasssyringeorofthenon-reinforcedrubber.