Infill selection for 3D printed radiotherapy immobilisation devices.

Area of Science:

• Medical Physics
• Materials Science
• Additive Manufacturing

Background:

• 3D printing offers novel applications in radiotherapy device fabrication.
• Process parameters' impact on 3D printed radiotherapy devices remains largely uncharacterized.
• Optimizing these parameters is crucial for device efficacy and patient safety.

Purpose of the Study:

• To investigate the influence of infill pattern, density, and print orientation on surface dose and mechanical properties of 3D printed samples.
• To identify optimal 3D printing parameters for radiotherapy devices, focusing on immobilization applications.
• To provide data for informed selection of 3D printing parameters in clinical settings.

Main Methods:

• Fused Deposition Modeling (FDM) used to print samples with ten infill patterns in two orientations.
• Surface dose measurements conducted using a Varian Truebeam linear accelerator (6 MV photon beam).
• Tensile strength evaluated using ASTM D638 type I standards on a 50 KN Instron 5969.

Main Results:

• Horizontal print orientation generally yielded lower surface doses than vertical.
• The 'Stars' infill pattern showed the lowest surface dose in horizontal orientation.
• The '3D Honeycomb' pattern exhibited the highest ultimate tensile strength (UTS) across orientations.
• The 'Stars' pattern demonstrated an optimal combination of low surface dose and good UTS.

Conclusions:

• Infill patterns significantly impact the dosimetry and mechanical performance of 3D printed radiotherapy devices.
• Print orientation and infill pattern are critical factors for surface dose and mechanical integrity.
• The 'Stars' infill pattern is recommended for applications requiring a balance between low surface dose and mechanical robustness.