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
http://solar.physics.montana.edu/martens/plasma/
Problem


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
Project Goal




To design and build a working gas-plasma
needle.
Prototype consists of plasma needle and
flexible catheter.
Prototype will deliver helium gas through
coaxial catheter to produce plasma
discharge.
The design must be safe for surgical use.
Requirements to Meet
Goals

Flexibility:
– Tungsten electrode
– Bending catheter should not affect gas helium flow
– Insulating material

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.
Rabbits will be used as experimental
subjects for this prototype.
Our Progress So Far
Research
 Literature from Eindhoven
 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
 Identified vendors for prototype parts
 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 1-100 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
The Development of a Smart-Scanning Probe for the Plasma Needle, Ewout van der Laan
diameter
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
Frequency = 13.56 MHz (universal)
Plasma resistance = 2 ohms
Needle resistance = 1.1 ohm
Needle Capacitance = 28.8 pF
Plasma discharge is purely resistive.
Helium flow = 0.1L/min
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 (15-120 pF)
Experimental setup
Materials
Equipment
Type
price
status
Function generator
HP 33210A 15MHz
$0
En route
Power Amplifier
Kalmus 125C-CE 0.5-50 MHz,
25 W, 45 dB
$0
En route
Power coupler
AR DC3002 0.1 - 1000 MHz
-
Pending
Power heads
AR PH2002
-
Pending
Power meter
AR PM2002
-
Pending
Flow controller
Mass flow controller Brooks
instrument
-
http://www.emersonprocess.com/br
ooks/sp210/sp210-1.html
Coaxial cables
RG 058 50 ohm
$3
http://www.cablewholesale.com/cat
alog/rg58coaxialcables.htm
Automatic RCL
meter
Fluke PM 6303A 1kHz
-
Pending
Wheatstone bridge
Rhode-Schwarz inductor
bridge
-
Pending
Voltage probe
Agilent N2771A 15kV 100 M/1
pF
-
Pending
Oscilloscope
Tektronix 2215 60 MHz
-
Pending
Photodiode
UV50 from UDT sensors, Inc.
-
Pending
Matchbox Materials
Equipment
Type
price
link
SpraqueGoodman
capacitor
GME50201
(15-120Pf)
Waiting on
quote
http://www.4starelectronics.
com/part_search/RFG.aspx
Temperature
Compensating
Dogbone
Capacitor
470pF-500v
$1.70
http://www.surplussales.co
m/Capacitors/RFTempDogbone.html
Temperature
Compensating
Dogbone
120pF1000v
$2.25
http://www.surplussales.co
m/Capacitors/RFTempDogbone.html
Temperature
Compensating
Dogbone
50pF-1000v
$2.50
http://www.surplussales.co
m/Capacitors/RFTempDogbone.html
Inductor
3.8(needs
3.4mH)
Waiting on
quote
http://www.coilcraft.com/spt
.cfm
inductor



Used to reduce
stray capacitance
3.4 micro-H
Found 3.8 micro-H
Experimental setup
Catheter Design

A potential analog to our design:
–LMGN-9.0C-90-ANG-HC
(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
December
Gas Plasma &
Catheter Research
January
Research & Design
of Catheter
February
Catheter
Construction
Construction of
Functioning Plasma
Needle Setup
March
April
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
 Sensing the gap width by monitoring the discharge power
consumption
Current:
 Control of the gap width with robotic
actuation
 Integration into catheter
Future:
 Testing in animal blood vessels