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 Design and Build a Working Plasma-catheter Design and Build a Working Plasma-catheter –Construct functioning basic plasma needle prototype –Design catheter –Build catheter design incorporating functioning plasma needle –Characterize plasma-catheter prototype –Refine design to suit surgical needs

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.

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

Our Progress So Far Arranging for Experimental Setup Consult Faculty Consult Faculty –Identify knowledge on campus. –Meet with these individuals to gain information, direction and advice. Finalize List of Materials Finalize List of Materials –Look into specifications and compatibility of products. –Order necessary materials. –Identify people who can help us put everything together.

Composition of Previous Basic Needle Prototype ____ 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

Plasma Needle Operating Characteristics  RF Frequency = MHz (universal)  P-P RF Voltage ~ V  Power Level ~ 100 – 400 mW  Needle Resistance = 1.1 ohm  Needle Capacitance = 28.8 pF  Plasma Resistance = 2 ohms  (Plasma discharge purely resistive)  Helium Flow = 0.1L/min  Minimum Ignition Voltage = 250 V

Solid Model of Test Rig for Plasma Needle Prototype Inner Diameter = 4mm Diameter of Tungsten Needle = 0.3mm Length = 5cm Helium Flow Rate < 1L/min Material: Glass glass Teflon coating tungsten helium RF 5 cm 2 mm

Plasma Needle Prototype Experimental Setup

Function Generator (Courtesy of our Dutch colleagues) RF Signal: MHz Max Power Output: 10 W

Variable Matchbox Z-11 QRP Automatic Antenna Tuner  Manufacturer: LDG Electronics Inc.  Size: 5.0 x 6.5 x 1.3” enclosure  Tunes ohm loads  Tuning time:.1-3 sec 1.8 – 30.0 MHz Coverage 1.8 – 30.0 MHz Coverage Power range:.1-30 W Power range:.1-30 W

Z-11 QRP Automatic Antenna Tuner  Config: Switched “L” network  Microprocessor Controlled Inductor range: 20 uH Inductor range: 20 uH Capacitor range: 2700 pf Capacitor range: 2700 pf

Helium Source  On hand in EE Welding Lab

Other Materials Needed  100 cm 50 ohm Coax cable (RG058)  25 cm 50 ohm Coax cable (RG058)  20 cm Tungsten wire  Photodiode?  Thermocouple?

Potential Catheter Designs Actuator Teflon coating tungsten helium RF 5 cm 1-2 mm He

Immediate Goals (through end of February) 1.Construction of plasma needle prototype  Purchase remaining materials  Perform P-Spice Simulation  Build matchbox tuner from kit  Construct experimental setup in EE Welding Lab  Run simulation and make necessary modifications 2.Contact Coordinating Group  Clarify necessary parameters for prototype operation characterization 3.Catheter Design Work  Gather opinions from local medical professionals  Evaluate pros and cons of potential designs  Select most promising design  Draw up detailed specifications  Continue research on appropriate selectively porous membranes

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

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 consumption Adapted positioning sensor Adapted positioning sensorCurrent: Design Plasma-Catheter Design Plasma-CatheterFuture:  Testing in animal blood vessels