An integrated endotracheal brachytherapy system: Engineering validation and dosimetric advantages

Area of Science:

• Medical Devices
• Radiation Oncology
• Biomedical Engineering

Background:

• Conventional applicators (e.g., Bonvoisin-Gérard applicator) have suboptimal positioning for tracheal brachytherapy.
• Tracheal brachytherapy requires precise dose delivery and stable applicator placement.

Purpose of the Study:

• To develop and validate a novel multichannel tracheal applicator (MTA) for patient-adapted tracheal brachytherapy.
• To assess MTA's integration with endotracheal tubes (ETT), ventilation compatibility, positional stability, and dosimetric performance.
• To address clinical needs in treating recurrent granulation tissue and primary tracheal carcinomas.

Main Methods:

• Anatomical modeling and device design based on 25 patient CT datasets.
• Validation using Computational Fluid Dynamics (CFD) simulations and bench experiments for ventilation and stability.
• Dosimetric evaluation via phantom radiochromic film measurements and comparison with the Bonvoisin-Gérard applicator (BGA).

Main Results:

• MTA demonstrated minimal airflow resistance within ETTs, with peak inspiratory pressure differences <2% and safe ventilation up to 500 mL TV.
• Simulated motion testing confirmed excellent positional stability (<0.5 mm displacement).
• Dosimetric evaluation showed 99% agreement between planned and measured doses, with improved conformity and OAR sparing compared to BGA.

Conclusions:

• The MTA overcomes geometric and stability limitations of conventional applicators, enabling precise, customizable tracheal brachytherapy.
• Validated airflow resistance, positional stability, and superior dosimetry provide strong proof-of-concept for MTA.
• MTA's performance justifies progression to early-phase clinical trials for safety, feasibility, and efficacy evaluation.