Fabrication of malleable three-dimensional-printed customized bolus using three-dimensional scanner

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Biomedical Engineering

Background:

• Conventional bolus fabrication for radiotherapy often relies on computed tomography (CT) scans, which can be complex and lead to unnecessary radiation exposure.
• Customized boluses are crucial for conforming to irregular patient surfaces, ensuring accurate dose delivery in radiotherapy.
• Existing methods for creating patient-specific boluses can be cumbersome and may involve radiation doses that are not therapeutically beneficial.

Purpose of the Study:

• To develop and evaluate a novel method for fabricating customized three-dimensional (3D)-printed boluses using 3D scanning technology.
• To assess the dosimetric properties and clinical applicability of 3D-scanned and printed boluses for irregular surfaces in radiotherapy.
• To compare the efficacy of 3D-scanned boluses with traditional CT-based fabrication and commercial bolus materials.

Main Methods:

• Utilized a 3D scanner to capture the surface geometry of an Alderson Rando phantom's head.
• Reconstructed 3D surface data using Geomagic Design X software to design a 5-mm thick, nose-conforming 3D bolus.
• Fabricated the 3D bolus using a rubber-like printing material and developed a radiotherapy plan for evaluation.

Main Results:

• Successfully fabricated a customized 3D bolus that accurately conformed to the phantom's irregular nasal surface without air gaps.
• CT simulation confirmed the acceptable fit of the 3D bolus.
• The 3D bolus demonstrated an enhanced surface dose compared to the phantom without a bolus, with percent depth dose (PDD) curves comparable to commercial superflab boluses.
• Radiotherapy planning incorporating the 3D bolus resulted in improved target coverage.

Conclusions:

• A customized 3D bolus for irregular surfaces can be effectively fabricated using 3D scanning, offering a more efficient and potentially safer alternative to CT-based methods.
• The 3D-scanned and printed bolus provides accurate surface conformity and enhances dose delivery in radiotherapy applications.
• This innovative approach improves radiotherapy planning and target coverage for patients with complex surface geometries.