1. Heated X-ray Examination Table
Team Leader: Tyler Vovos
BWIG: Joel Gaston
BSAC: Joey Labuz
Communicator: Paul Schildgen
Client: Lanee MacLean
Advisor: Mitch Tyler

2. Overview Background Information Problem Statement
Design Specifications
Proposed Design
Heating Material Options
Design Matrix
Future Work

3. Background Information
Diagnostic use of X-ray
Density of body structures
Skeletal pathologies, some soft tissue applications
Anatomy vs. physiology
Duration of procedure
Current exam table
Hard laminate surface
Dimensions 2.2 x .75 m
In medicine X-rays are primarily use to image the anatomy of the body. One of the most common uses of x-ray is in the diagnosis of skeletal pathologies. The duration of a procedure can vary from minutes to around an hour, during which time it is usually necessary for the patient to remain still. The exam table we are working with is shown. Note the hard laminate surface where a patient would lie.

4. Problem Statement Current X-ray examination tables are uncomfortable
Hard
Cold
Discomfort may cause patient movement
Long examination duration
Not available commercially
A common patient complaint is that x-ray tables are too hard and too cold. It is our goal to find a solution to this probem.

5. Design Specifications
Materials/design must be radiolucent
No anatomical distortion
Must incorporate patient or technician control
Must not obstruct the technician’s workspace
Patient safety
Limited budget
Our device must be almost completely radiolucent. We have to consider how specific materials, temperatures, and designs will cause x-ray attenuation or introduce contrast into the image. Also, it is important that our device does not alter the normal anatomy of the patient (hard/soft spots). Because the device is intended to provide the patient with a comfortable temperature, they must have control. Finally, we have the extra challenge of designing and creating a prototype with a limited budget.

6. Proposed Design Thermistor Microcontroller
Upper Layer of Electrically Insulating Material and/or Padding
Lower Layer of Electrically Insulating Material
Heating Element
Voltage Source
Conducting material
Microcontroller
Thermistor 6

7. EEONFELT (Polyaniline Dipped Nylon)
Pros:
Even heating
Adjustable resistivity (20 Ω/square to 106 Ω/square)
Very flexible
Cons:
Unknown degradation
Limited commercial availability 7

8. Carbon Fiber Pros: Commercially Available Thickness: < 0.4mm
Non-degradable
Safe, even distribution of heat
Cons:
Non-uniform
Maximum Temperature: 27.8°
Limited flexibility 8

9. Kapton 200RS100 Film (Polyimide)
Pros:
Commercially available
Stable up to 350 °C
Even heating
Uniform
Thin (~0.5 mm)
Flexible
Cons:
Unknown degradation
Dupont.com 9

10. Indium Tin Oxide Film Pros: Commercially available
Adjustable resistivity
Thin ITO layer (~100 nm)
Uniform ITO deposition
Cons:
Degrades under repeated bending 10

11. Materials Matrix Weight Kapton ITO Film Carbon Fiber EEONFELT
Uniformity 30 27 12
Heating 20
TEST
Radiolucency 15
Degradation
Flexibility 10 9 8
Cost 7
TOTAL
100
49+
42+
39+
48+ 11

12. Future Work Purchase all necessary materials Testing protocol:
Resistivity using multi-meter
Heating using infrared thermometer
Radiolucency using exponential attenuation law
Degradation using stress/strain analysis, and long X- ray exposure
Scale up using:
Ohm’s law
Thermodynamic principles
Exponential Attenuation Law

13. References
Bird, B., Lightfoot, E., Stewart, W., Transport Phenomena. New York: Wiley and Sons
Links, J. M., Links, J., Prince, J., Medical Imaging Signals and Systems. Prentice Hall, 2005.
Personal Interview with Dr. Frank Ranallo
Personal Interview with Dr. John Vetter
Personal Interview with Dr. Wally Block
Personal Interview with Dr. Wally Peppler
Personal Interview with Prof. John Yin
Testing with Lanee MacLean

14. Questions?

15. Material Heating
Governed by Fourier’s law of conduction and Newton’s law of cooling
Fourier
Newton
h = heat transfer coefficient
~6 (w/m2K)
k = thermal conductivity
~0.4 (w/mK)
Foam Pad TA Q Q Q Q T1 y T0
Heating Element 15

16. X Ray Attenuation Mass Attenuation Coefficient (µ/ρ)
Dependent on Photon Energy ( keV for Diagnostic X-rays). Testing at ~80 KeV would maximize attenuation effects.
Require substantially less than 10% attenuation of beam, ideally < 1 % (99 % transmission).
I = End intensity
IO = Incident intensity
µ = Mass attenuation coefficient
p = Material density
x = Material thickness 16

17. X Ray Intensity vs. Energy Spectrum
Testing Region (~ 30 to 40 Kev)
Max. Photon
Energy (80 KeV)
Original Beam
Transmitted Beam
(Actual Image)
30 Kev
40 Kev
Energy (KeV) 17 17