Dosimetric Validation and Surface Fit Evaluation of 3D-Printed Dose Boluses for Radiation Therapy Applications

Background: In modern radiation therapy, accurate dose delivery to tumor sites while sparing surrounding healthy tissue is paramount. A dose bolus, commonly employed to modulate surface dose distribution, ensures effective treatment. Objectives: The present study focuses on the dosimetric validation of 3D-printed dose boluses by comparing their effective performances to the targeted ones when creating the virtual boluses by the clinician on the treatment planning system (TPS). Methods: The research involves the fabrication of 3D-printed boluses using flexible thermoplastic polyurethane filament (TPU) and the assessment of their dose delivery accuracy using “Eclipse” and “Monaco” TPS. By considering 3 treatment cases and clinical locations, namely: Frontal lobe, right breast and inguinal region, the validation process was based on the measurement and comparison of dose profiles across the air/bolus/tissue interfaces, dose coverage: D98%, D95%, D50%, D2% and Dmean, dose Homogeneity Index (HI), and dose Conformity Index (CI). How boluses fit the received surfaces was also checked through CT scanning. Results: The results demonstrate that 3D-printed boluses offer superior conformity to patient-specific anatomy, leading to improved surface dose distribution. Overall, the 3D-printed boluses exhibit optimal dosimetric performances that conform to the targeted ones, with the added benefits of customization and ease of production. Conclusions: This study highlights the potential of 3D printing technology to enhance radiation therapy by providing flexible, patient-specific solutions for the fabrication of dose bolus while maintaining the dosimetric integrity required for an effective and accurate treatment.