Group 10:Corynne Hume presenter

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• Group 10 Corynne Hume (presenter)
• Holly Rockweiler
• Andrew Killips
• Mentor Sasa Mutic

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Design Requirements

• The mask must
• Immobilize patient to within 3 mm
• Be cast by one technician
• Limit Shrinkage
• Reduce repositioning deviations between fractions
• Allow for use of anesthesia tube
• Will not attenuate radiation
• Last for 30-40 fractions
• Cost less than 500

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Design Parts

• Mask
• Chin Strap
• Head Block
• Couch Modifications
• Attachment Rods

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Mask

• Clipping U-frame allows use of twice as much
  thermoplastic, decreasing shrinkage potential
• Reinforcements stabilize rigid areas of the face
• Open area at the top of the head leaves room for
  head block
• Mask ends at maxilla decreasing shrinkage at the
  chin and allowing easy access for anesthesia tubes

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Mask

• Porous thermoplastic material for the mask
• U-frame with Clip made of Delrin
• Reinforced in same areas as in the Medtec mask
  and along the bottom at the maxilla

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Chin Strap

• Chin strap serves to stabilize mandible
• Holes fit over knobs on the couch
• After initial placement the excess can be cut off
  to permanently mark strap length
• The chin strap will be made of silicone rubber

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Chin Strap Positioning Analysis

• To secure the mandible, the straps must be angled
  correctly
• To offset the possible downward movement of the
  mandible, the top strap must be angled

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Head Block

• The head block sets a localization point between
  fractions
• The existing masks do not offer a point off of
  which the patient can be sure they were
  positioned at the last sitting

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Head Block

• The head block will be made of Delrin
• The base is made of Lucite
• The head block will be attached to the grid of
  the couch by four nylon screws

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Couch Modifications

• The couch is an existing piece of the current
  immobilization devices.
• Additions of our design include
• Nylon knobs
• for chinstrap
• attachment
• Nylon eyelets
• for mask
• attachment

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Rods

• The rods are made of nylon
• They slide through the eyelets on the couch and
  hold in the mask
• There are two rods per mask, one on each side
• The handle at the end will improve the ease of
  positioning for the technician

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Manufacturing Process

• Mask
• U-frame cut out of Delrin sheet along with clasp
• Thermoplastic fused to frame with and epoxy
• Chin Strap
• Silicone rubber poured into mold
• For the prototype it will be cut out of a sheet
  of silicon
• Head Block
• Delrin will be cut down

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Manufacturing Process

• Couch Modifications
• Holes drilled into carbon fiber couch with a
  diamond or carbide drill tip
• Knobs and eyelets will be machined by cutting
  them down to specified dimensions
• Knobs and eyelets set into couch with an epoxy
• Rod
• Cut from sheet of nylon
• Handles attached

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Manufacturing Estimate
Prototype will cost 1700
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Conclusions

• Requirements Met
• Immobilize Patient to within 3 mm
• Cast by one technician
• Limit Shrinkage
• Reduce repositioning deviations
• Opening for anesthesia tube
• Will not attenuate radiation
• Last for 30-40 fractions
• Cost

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IP Considerations

• Our design is patentable because it is novel and
  useful.
• Our design will be licensed to Medtec. They will
  manufacture the mask and attachments.
• The goal of our design was to improve the
  accuracy of radiation oncology not to begin our
  own manufacturing company.

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Design Safe Analysis

• Highest risks include
• Psychological effects of and risks of entrapment
• Radiation
• Abrasion
• Burns
• Trapping and radiation exposure are the purpose
  of the mask.
• Anesthesia can be administered if patient is
  uncomfortable.
• The mask is thin and porous to reduce the risks
  of burns from radiation.
• Technician training will diminish these risks.

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Future Directions

• Clinical Trials
• Control subjects
• Position imaged through Infrared camera
• Future Adaptations
• Moldable Head Block
• Release Mechanism
• Lessons Learned
• In industry precedence is on profitability
  before functionality

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Questions?