Stereotactic Device

1
Stereotactic Device

• Team Members
• Team Leader- Jeremy Glynn
• Communicator- Jeremy Schaefer
• BSAC- Mike Conrardy
• BWIG- Adam Goon
• Client- Ian Rowland, Ph.D., Department Of
  Radiology
• Advisor- Professor Bill Murphy

2
Overview

• Background Information
• Problem Statement
• Motivation
• Client Requirements
• Existing Technology
• Design Alternatives
• Design Matrix
• Future Work
• Questions?

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Background Information

• Basics of MRI (Magnetic Resonance Imaging)
• Generates very strong (4.7 T) magnetic field
• Causes atoms to emit radiowaves
• Uses of MRI
• MR images provides information such as
• Size of tumors
• Functions of organs
• Chemical concentrations
• Clients focus Brain imaging

http//en.wikipedia.org/wiki/Magnetic_resonance_im
aging
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Problem Statement

• Design a stereotactic device that will
• Minimize head movement of rats/mice while
  positioned in MRI
• Incorporate a heating device to prevent
  hypothermia
• Fit within the MRI coil
• Allow for provided anesthetic

MRI Coil for imaging rats Captured 2/5/08, UW
Hospital
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Motivation

• Imaging quality and efficiency
• Allow for imaging over a longer time period
• Animals metabolic rates decrease with anesthesia
• Can lead to hypothermia or death
• Anesthetic can be connected quickly and easily
• Animal can be positioned with ease
• Animal safety
• Current heating methods are inadequate

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Client Requirements

• Cant interfere with MRI images
• Animals brain must be centrally aligned in MRI
• Heating device to warm animal
• Within 5o of 37oC
• Fit inside MRI coils
• Rat- 63 mm diameter
• Mouse-36 mm diameter
• Anesthetic mask must cover animals mouth
• Minimal movement of animal
• Restraint without harm
• Withstand 4.7 Tesla magnetic field

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Existing Stereotactic Devices

• David KOPF Instruments
• Model 324 MRI Head Holder
• for Rat
• Model 325 MRI Head Holder
• for Mouse
• Model 923M MRI Mouse Gas
• Anesthesia Adaptor
• Enzyme Research Facility

http//www.kopfinstruments.com/Stereotaxic/ Stereo
taxicPrintables/324-325-P.pdf
Enzyme Research Facility (Beth Rauch)
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Our Restraining Device

• Tooth restraint does not obscure anesthetic mask.
• Fits inside MR tray
• Recessed in tray for proper brain alignment.

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Air Chamber

• Advantages
• Inexpensive
• Disadvantages
• Difficult to move heated air efficiently
• Air has less effective heat transfer
• Larger volume of air to heat

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Fluid Piping

• Advantages
• Easy to manufacture
• Water has better thermal conductivity
• Accessory parts inexpensive
• Disadvantages
• 3D printing expensive
• Possibility water could leak

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Air Piping

• Advantages
• Easy to manufacture
• No possibility of leaking water
• Disadvantages
• Air has low thermal conductivity
• Difficult to move heated air through small
  diameter tube

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Design Matrix
Cost (0.05) Durability (0.20) Heat Consistency- Quality of Circulation (0.30) Heat Transfer - Efficiency (0.25) Ease of Manufacturing (0.20) Total
Air Chamber 8 (.4) 8 (1.6) 4 (1.2) 6 (1.5) 6 (1.2) 5.9
Fluid Piping 5 (.25) 7 (1.4) 9 (2.7) 8 (2) 7 (1.4) 7.75
Air Piping 6 (.3) 8 (1.6) 7 (2.1) 5 (1.25) 6 (1.2) 6.55
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Future Work

• Research
• Pumping/Heating design
• Start up time
• Efficiency
• Testing
• Heat lost through piping
• Durability of 3D printing material
• Temperature of heating pad
• Temperature of fluid

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Questions?