bhpa

1. Use of 3D printing to generate patient-specific
electron beam aperture blocks
S Michiels1, B Mangelschots2, C Devroye2, T Depuydt1,2
1KU Leuven - University of Leuven, Department of Oncology, Laboratory of Experimental Radiotherapy, Leuven, Belgium
2University Hospitals Leuven, Department of Radiation Oncology, Leuven, Belgium
PURPOSE
METHODS AND MATERIALS
RESULTS
CONCLUSION
e-mail: michiels.steven@kuleuven.be
3D Printer
• Electron beam collimators for non-standard field sizes or for irregular
field shapes typically fabricated in Cerrobend using Styrofoam molds
Requires a dedicated foam-cutting machine
• Additive manufacturing is finding its way into several applications in
radiation oncology, e.g. patient-specific bolus, phantom creation,
immobilization, …
Allows the use of a single 3D printing device
for a range of applications
Proof-of-concept study of a 3D printing solution for the creation of patient-specific aperture blocks
• Electron beam planning, including determining the field aperture
• Export RT PLAN DICOM from the treatment planning system
• Create patient-specific 3D-printable mold and export as standard tesselation (.stl) file using
open source programming (Python v3.6) and computer-aided design software (FreeCAD v0.16)
• Integration of
• Dosimetric comparison of conventional clinical workflow using styrofoam vs. 3D printing workflow
- Dose distribution measurements using radiochromic film at 2 cm depth in a polystyrene slab phantom
- Gamma-index analysis between both measurements using 1.5 % dose-difference and
1.5 mm distance-to-agreement acceptance criteria
Beam’s eye view of the clinical field:
Planning target volume and required
aperture
Patient-specific 3D printed mold and positioning device (A) fit onto the block tray (B), and the resulting aperture block (C).
-Patient ID-number in the mold  process tracking
- Key to attach the mold to a reusable 3D-printed positioning device
 ensure correct alignment of the mould in the tray
2D dose distribution (A) and line profiles along the X-axis (B) and Y-axis (C).
Gamma-index
agreement score:
98.5%
• Standardized, operator-friendly workflow, without the need for specific equipment
• Increased safety and quality of the patient, including patient identification and error-safe mold positioning
3D printing technology allows for