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Validation of Patient-Specific 3D-Printed Bolus Caps for Clinical Use in Total Scalp Irradiation

G C Baltz*, P Chi, P Wong, C Wang, D Craft, S Kry, S Lin, A S Garden, R M Howell, MD Anderson Cancer Ctr., Houston, TX


(Wednesday, 8/1/2018) 9:30 AM - 10:00 AM

Room: Exhibit Hall | Forum 7

Purpose: We have previously presented a workflow for the fabrication of patient-specific 3D-printed bolus caps for use in Total Scalp Irradiation (TSI). Two bolus caps fabricated for an anthropomorphic head phantom, one 3D-printed in-house and one externally, proved to have good conformality to the scalp, with minimal air gaps. The purpose of this study was to show the clinical efficacy of using the 3D-printed bolus caps for TSI through setup reproducibility and dosimetric validation measurements to demonstrate the 3D-printed bolus caps can reproducibly generate a homogeneous dose to the scalp.

Methods: Two CT simulations for TSI were acquired of an anthropomorphic head phantom, one fitted with the in-house printed bolus cap and one fitted with the external 3D-printed bolus cap. Volumetric-modulated arc therapy TSI plans were generated for each CT simulation. Flat-pack thermoluminescent dosimeters (TLD) were placed in 20 locations in the treatment area on the phantom scalp and the respective planned treatment was delivered for each bolus cap. TLD measured doses were compared to doses calculated by the treatment planning system (TPS). To study reproducibility, three different radiation therapists independently setup the phantom and bolus in the treatment setup and CT scans were acquired to measure bolus positioning compared to the original CT simulation.

Results: TLD measurements showed that both bolus caps generated a homogeneous dose to the scalp within 2.7% standard deviation. The TPS calculated doses agreed with measured doses to within 2.41% on average. CT scans acquired from the reproducibility study demonstrated bolus positioning was consistent to within 2 mm compared to original simulation.

Conclusion: We have shown that the 3D-printed bolus caps fabricated by our workflow can be reproducibly setup for treatment and generate a uniform dose to the phantom scalp.


3D, Treatment Techniques, Surface Dose


TH- External beam- photons: Development (new technology and techniques)

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