Dustin Borg, ME Patrick Henley, BME Ali Husain, BME Nick Stroeher, BME Advisor: Dr. Paul King

What is Plasma? Plasma is a state of matter with enough free charged particles so that its dynamics are heavily influenced by electromagnetic forces.  gaseous fluid-like mixture of ions, free electrons,radicals and excited atoms and molecules The Plasma Needle uses Low-Temperature Plasma (LTP)  small fraction of neutral particles in gas are ionized  electrons are high energy; ions are ambient temp.  retains neutral charge

Problem Plaque can build up in blood vessels leading to infarctions, stoppage in blood flow or possibly to heart attack Plaque can build up in blood vessels leading to infarctions, stoppage in blood flow or possibly to heart attack Our approach to this problem is to develop a novel and safe treatment to remove plaque without causing cell necrosis in the surrounding tissue Our approach to this problem is to develop a novel and safe treatment to remove plaque without causing cell necrosis in the surrounding tissue

Project Goal To design and build a working gas-plasma needle. To design and build a working gas-plasma needle. Prototype consists of plasma needle and flexible catheter. Prototype consists of plasma needle and flexible catheter. Prototype will deliver helium gas through coaxial catheter to produce plasma discharge. Prototype will deliver helium gas through coaxial catheter to produce plasma discharge. The design must be safe for surgical use. The design must be safe for surgical use.

Requirements to Meet Goals Flexibility: Flexibility: –Tungsten electrode –Bending catheter should not affect gas helium flow –Insulating material Safety: Safety: –Helium flow no greater than 100 cc/min –Separating material between plasma discharge and biological tissue –No blood flowing into catheter and no bubbles going into bloodstream

Additional Requirements Maximum size of catheter should be 1-2 mm diameter to fit into blood vessels. Maximum size of catheter should be 1-2 mm diameter to fit into blood vessels. Rabbits will be used as experimental subjects for this prototype. Rabbits will be used as experimental subjects for this prototype.

Our Progress So Far Research Literature from Eindhoven Literature from Eindhoven Independent Research: Independent Research: –Compatibility of helium gas with biological tissue –Effect of free radicalization on cell-adhesion molecules –Design more flexible needle for catheter Coordination NetMeeting NetMeeting Identified vendors for prototype parts Identified vendors for prototype parts Potentially procured lab space after review of technical specifications in the EE welding lab Potentially procured lab space after review of technical specifications in the EE welding lab

Composition of the Needle ____ The AC source produces Radio Frequent (RF) discharges on the order of MHz ____ This design uses Capacitively Coupled Plasma to create E field from voltage difference ____ In the middle is a metal wire with a sharp point  electrode for the E field ____ The coaxial metal tube is grounded  Helium gas is moved into space between ____ Wire is insulated so that plasma is generated only at tip; it appears like a ball 1 mm in diameter ____ The Development of a Smart-Scanning Probe for the Plasma Needle, Ewout van der Laan

Current Known Effects Main effect is the dissolution of tissue Most likely Plasma Needle damages CAM proteins and causes breakup of tissue without accidentally killing cells Destruction of CAM  proliferation of free radicals (O, OH) The Development of a Smart-Scanning Probe for the Plasma Needle, Ewout van der Laan

Catheter Specifications Length = 5 cm Length = 5 cm Frequency = MHz (universal) Frequency = MHz (universal) Plasma resistance = 2 ohms Plasma resistance = 2 ohms Needle resistance = 1.1 ohm Needle resistance = 1.1 ohm Needle Capacitance = 28.8 pF Needle Capacitance = 28.8 pF Plasma discharge is purely resistive. Plasma discharge is purely resistive. Helium flow = 0.1L/min Helium flow = 0.1L/min Minimum voltage to ignite plasma = 250 V Minimum voltage to ignite plasma = 250 V

Matching Network

Variable Matchbox –Connects two circuits together via a network in such a way that the maximum transfer of energy occurs between the circuits. –The max transfer occurs when the impedances of those two circuits are equal. (source and plasma) –Better: power that has to be delivered by the amplifier reduces with a factor of 10. –Tunable –Cheap –Small: 25X25X9mm –Very large capacitance ranges ( pF)

Experimental setup Materials EquipmentTypepricestatus Function generatorHP 33210A 15MHz$0En route Power AmplifierKalmus 125C-CE MHz, 25 W, 45 dB $0En route Power couplerAR DC MHz-Pending Power headsAR PH2002-Pending Power meterAR PM2002-Pending Flow controllerMass flow controller Brooks instrument - ooks/sp210/sp210-1.html Coaxial cablesRG ohm$3http:// alog/rg58coaxialcables.htm Automatic RCL meter Fluke PM 6303A 1kHz-Pending Wheatstone bridgeRhode-Schwarz inductor bridge -Pending Voltage probeAgilent N2771A 15kV 100 M­/1 pF -Pending OscilloscopeTektronix MHz-Pending PhotodiodeUV50 from UDT sensors, Inc.-Pending

Matchbox Materials EquipmentTypepricelink Spraque- Goodman capacitor GME50201 (15-120Pf) Waiting on quote com/part_search/RFG.aspx Temperature Compensating Dogbone Capacitor 470pF-500v $1.70http:// m/Capacitors/RF- TempDogbone.html Temperature Compensating Dogbone 120pF- 1000v $2.25http:// m/Capacitors/RF- TempDogbone.html Temperature Compensating Dogbone 50pF-1000v $2.50http:// m/Capacitors/RF- TempDogbone.html Inductor3.8(needs 3.4mH) Waiting on quote

inductor Used to reduce stray capacitance Used to reduce stray capacitance 3.4 micro-H 3.4 micro-H Found 3.8 micro-H Found 3.8 micro-H

Experimental setup

Catheter Design A potential analog to our design: A potential analog to our design: –LMGN-9.0C-90-ANG-HC (Cook Diagnostic and Interventional Products) (Cook Diagnostic and Interventional Products)

Immediate Goals (next two weeks) 1.Construction of plasma needle prototype  Buy components  Lab space  Acquire generator  Consult an electrical engineering professor / technician 2.Focused research efforts  Catheter  Materials  Specifications  Selectively Porous Membranes

Timeline DecemberJanuaryFebruaryMarchApril Gas Plasma & Catheter Research Construction of Functioning Plasma Needle Setup Research & Design of Catheter Catheter Construction Physical Testing and Refinement of Prototype

Our Dutch Counterparts Willem-Jan van Harskamp, Applied Physics Vivian Roode, BME Gijs Snieders, BME M. van Vlimmeren, BME Advisor: Dr. Eva Adamowicz

Level of Development of Plasma Needle Technology Completed: Evaluation of the electrical characteristics of the plasma needle Evaluation of the electrical characteristics of the plasma needle Sensing the gap width by monitoring the discharge power consumption Sensing the gap width by monitoring the discharge power consumptionCurrent: Control of the gap width with robotic actuation Control of the gap width with robotic actuation Integration into catheter Integration into catheterFuture:  Testing in animal blood vessels