A novel dose-based intra-preplan method for high-dose-rate brachytherapy in cervical cancer using modeling and...

Area of Science:

• Medical Physics
• Radiation Oncology
• Oncology

Background:

• Intracavitary/interstitial brachytherapy (IC/ISBT) is crucial for cervical cancer treatment.
• Optimizing catheter configuration is key to effective dose delivery and minimizing toxicity.
• Current methods may not fully leverage patient-specific anatomy for optimal planning.

Purpose of the Study:

• To introduce and evaluate the clinical feasibility and efficacy of the dose-based intra-preplan (DIP) method for IC/ISBT in cervical cancer.
• To assess if DIP can optimize catheter configurations for improved dose distribution.
• To compare DIP with conventional intra-preplan (IP) methods.

Main Methods:

• The DIP method utilizes Oncentra Brachy's implant modeling and inverse planning optimization.
• Virtual applicator and catheter models were merged with patient CT images.
• An optimization algorithm determined optimal catheter number, positions, and depths.
• Retrospective validation in 14 IC/ISBT patients using Geneva applicators.
• Comparison of DIP and IP methods using dose-volume histogram (DVH) parameters for CTVHR and OARs.

Main Results:

• The DIP workflow was successfully implemented.
• DIP achieved comparable DVH parameters for CTVHR and OARs compared to IP.
• DIP used significantly fewer catheters than the IP method (p < 0.01).
• Adding catheters did not significantly improve DVH parameters, while reducing them compromised CTVHR coverage and increased OAR doses.

Conclusions:

• The DIP method allows for patient-specific optimization of minimal catheter configurations in IC/ISBT.
• DIP supports the wider implementation of high-quality brachytherapy for cervical cancer.
• This method enhances treatment planning by focusing on optimal dose distribution.