3D-printed personalized bolus designed through structured-light scanning for adaptive radiotherapy

Abstract

Conformal dose delivery in external beam radiotherapy often requires a tissue‐equivalent bolus to compensate for surface irregularities and increase skin dose. However, traditional bolus fabrication methods are time‐consuming, imprecise, and poorly adaptable to patient anatomy. This study presents an alternative, innovative workflow that integrates three-dimensional (3D) structured-light scanning (SLS), computer-aided design, and 3D printing to rapidly and accurately fabricate patient‐specific boluses. First, a chin bolus was generated within the treatment planning system using a Rando anthropomorphic phantom as a reference. The generated bolus was then processed, 3D-printed, and tested. To avoid additional computed tomography scans and unnecessary X-ray exposure, a high‐resolution, inoffensive SLS scanner was used to capture the treatment surface. The resulting point‐cloud data were imported into 3D modeling software to design a custom bolus geometry that conforms exactly to the patient’s skin contour. The workflow also incorporated a rapid rescanning and reprinting loop, enabling intra‐fractional and inter‐fractional modifications in response to anatomical changes. The 3D‐printed bolus demonstrated excellent conformity to the phantom surface. The entire process, from scanning to bolus deployment, was completed within a reasonable timeframe, substantially reducing patient waiting time compared with conventional methods. Overall, the proposed 3D printing-based workflow offers a rapid, accurate, and patient-specific alternative to conventional bolus fabrication. By leveraging SLS and digital modeling, this approach enhances conformity, improves dosimetric accuracy, and allows agile modifications to accommodate anatomical changes, thereby optimizing radiotherapy treatment delivery.

Keywords

Radiotherapy / Patient-specific bolus / 3D printing / Structured-light scanning / 3D modeling / Rapid fabrication and modification

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