Intensity Modulated High Dose Rate (HDR) Brachytherapy Using Patient Specific 3D Metal Printed Applicators: Proof of
James J Sohn1, Mitchell Polizzi1, Sang-Won Kang2
1Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, United States.
Frontiers in Oncology
|July 18, 2022
Summary
This study introduces 3D metal printing for patient-specific applicators in intensity-modulated brachytherapy (IMBT). This novel approach significantly improves target coverage for cancer treatment compared to conventional methods.
Area of Science:
- Medical Physics
- Radiation Oncology
- Biomedical Engineering
Background:
- High-dose-rate (HDR) brachytherapy often requires anisotropic dose distributions for optimal therapeutic index, especially with challenging patient anatomy.
- Existing intensity-modulated brachytherapy (IMBT) methods face practical limitations due to extended delivery times and complex mechanisms.
- A need exists for improved brachytherapy techniques that offer precise dose tailoring to individual patient anatomy.
Purpose of the Study:
- To present a novel approach for intensity-modulated brachytherapy (IMBT) using patient-specific applicator design with 3D metal printing.
- To develop and implement an inverse plan optimization model for designing 3D printed applicators for HDR brachytherapy.
- To achieve non-isotropic dose distributions tailored to individual patient anatomy for improved target coverage.
Main Methods:
- Designed patient-specific HDR applicators with internal shielding walls divided into adjustable sections.
- Developed a mathematical model to optimize shielding thicknesses and dwell times using inverse planning and alternating minimization.
- Utilized 3D modeling software and 3D metal printing for applicator fabrication; tested with digital phantoms and a simulated cervical cancer patient.
Main Results:
- The 3D printed applicator significantly improved target dose coverage compared to conventional methods in both phantom (99.18% vs. 58.32%) and clinical cases (99.92% vs. 56.21%).
- The proposed method successfully met treatment constraints for organs at risk (OARs) in all tested scenarios.
- Demonstrated the feasibility of producing non-isotropic dose maps with optimized shielding for conformal treatment planning.
Conclusions:
- The study successfully simulated IMBT with inverse planning using a novel 3D printed applicator design.
- This approach enables the creation of patient-specific, non-isotropic dose distributions tailored to individual anatomy.
- The 3D printed applicator offers a promising solution for more conformal and effective brachytherapy treatment planning.
