Program Information
Dosimetric Verification of 3D Printed Electron Bolus
K Rasmussen*, M Corbett , C Pelletier , Z Huang , Y Feng , J Jung , East Carolina Univ, Greenville, NC
Presentations
SU-C-213-6 (Sunday, July 12, 2015) 1:00 PM - 1:55 PM Room: 213
Purpose: To determine the dosimetric effect of 3D printed bolus in an anthropomorphic phantom.
Methods: Conformable bolus material was generated for an anthropomorphic phantom from a DICOM volume. The bolus generated was a uniform expansion of 5mm applied to the nose region of the phantom, as this is a difficult area to uniformly apply bolus clinically. A Printrbot metal 3D Printer using PLA plastic generated the bolus. A 9MeV anterior beam with a 5cm cone was used to deliver dose to the nose of the phantom. TLD measurements were compared to predicted values at the phantom surface. Film planes were analyzed for the printed bolus, a standard 5mm bolus sheet placed on the phantom, and the phantom with no bolus applied to determine depth and dose distributions.
Results: TLDs measured within 2.5% of predicted value for the 3D bolus. Film demonstrated a more uniform dose distribution in the nostril region for the 3d printed bolus than the standard bolus. This difference is caused by the air gap created around the nostrils by the standard bolus, creating a secondary build-up region. Both demonstrated a 50% central axis dose shift of 5mm relative to the no bolus film. HU for the bolus calculated the PLA electron density to be ~1.1g/cc. Physical density was measured to be 1.3g/cc overall.
Conclusion: 3D printed PLA bolus demonstrates improved dosimetric performance to standard bolus for electron beams with complex phantom geometry.
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