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Session: Therapy: Electron Treatment [Return to Session]

Verification of a Cost-Effective and Cerrobend-Free Workflow for Customized 3D-Printing Based Skin Collimation

M Polizzi*, J Sohn, S Kim, Virginia Commonwealth University, Richmond, VA


SU-IePD-TRACK 6-6 (Sunday, 7/25/2021) 3:00 PM - 3:30 PM [Eastern Time (GMT-4)]

Purpose: Secondary skin collimation is the optimal methodology for reducing electron scatter and preventing irradiation of non-involved tissue. However, the process of molds is cumbersome and commercial solutions are cost-prohibitive. We investigate the feasible clinical use of a 3D printed shaper filled with tungsten balls for skin collimation.

Methods: Using a 3D model a 3D printing based skin collimator (3D-SC) was produced. The thickness of the 3D-SC was set at 8 mm and filled with 2 mm tungsten balls (17.5 g/cm³). Measurements were performed with 6 MeV in solid water at 0.5 cm depth with Gafchromic™ EBT3 films. The film was irradiated with 300 MU. The irradiated film was scanned and analyzed with an OmniPro I’mRT (IBA Dosimetry). A clinical case is used to demonstrate the ease of implementation.

Results: The penumbra (90% to 20%) value measured was 0.175 mm for the 3D-SC. Compared to this, the conventional Cerrobend cut-out created 0.72 mm penumbra. The total print time of the 3D-SC was less than 5 hours. Once the CT scan was acquired, our clinical case was modeled in our 3D planning software within 30 minutes.

Conclusion: Skin collimation’s efficacy is confirmed with the 3D-SC. This process is efficient (e.g., less labor-intensive than molding), cost-effective, and the shielding (tungsten balls) is reusable. Future work will verify this methodology with additional patient cases involving large curvature and irregularity.



    Electron Therapy, 3D, Conformal Radiotherapy


    TH- External Beam- Electrons: Development (new technology and techniques)

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