Clinical Application of Patient-Specific Bolus Based on Molding and Casting Method in Radiotherapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomaterials Engineering

Background:

• Patient-specific boluses are crucial for precise radiation dose delivery, especially on irregular surfaces.
• Conventional boluses often result in air gaps and poor conformity, compromising dose distribution.
• Limitations of traditional boluses necessitate innovative fabrication methods.

Purpose of the Study:

• To develop and assess a novel patient-specific bolus fabrication method using mold-and-casting (M&C).
• To integrate 3D printing and silicone casting for improved bolus conformity and dose accuracy.
• To evaluate the geometric accuracy, dosimetric performance, and biocompatibility of the novel bolus.

Main Methods:

• A workflow involving CT imaging, 3D modeling, 3D printed mold fabrication, and silicone casting was established.
• Geometric accuracy was verified using surface matching and cross-sectional analysis.
• Dosimetric performance was evaluated with in vivo MOSFET measurements, and biocompatibility was assessed via standardized tests.

Main Results:

• The M&C fabricated boluses exhibited high geometric fidelity with <3% volumetric and surface discrepancies.
• In vivo dosimetric evaluations showed dose differences within the clinically acceptable ±5% range.
• Biocompatibility testing confirmed the silicone material's safety for clinical application.

Conclusions:

• The mold-and-casting method provides an efficient workflow for patient-specific bolus fabrication.
• This technique significantly reduces air gaps and improves surface dose uniformity compared to traditional boluses.
• The M&C method holds clinical potential for enhancing precision and efficiency in radiation therapy.