Optimizing Dual-layer Neutron Moderators for Accelerator-based Boron Neutron Capture Therapy: A Geant4 Simulation...

Area of Science:

• Medical Physics
• Materials Science
• Radiation Oncology

Background:

• Accelerator-based Boron Neutron Capture Therapy (BNCT) is a promising cancer treatment.
• Optimizing moderator materials is crucial for enhancing BNCT efficacy and safety.
• Current beam-shaping assemblies require further development for clinical applications.

Purpose of the Study:

• To investigate the impact of two-layer moderator material combinations on BNCT performance.
• To evaluate the effectiveness of different material pairings in delivering therapeutic neutron doses.
• To assess the safety profile by analyzing radiation levels within and outside a simulated tumor.

Main Methods:

• Utilized Geant4 Monte Carlo simulations to model neutron and gamma radiation transport.
• Tested 16 distinct two-layer combinations of aluminum oxide (Al2O3), titanium(III) fluoride, lithium bromide (LiBr), and lithium carbonate.
• Employed a weighted scoring system to assess treatment effectiveness and patient safety.

Main Results:

• The LiBr dual-layer configuration (Configuration N) maximized thermal neutron dose to the tumor.
• The Al2O3 double-layer configuration (Configuration P) significantly reduced radiation outside the tumor.
• The LiBr + Al2O3 combination (Configuration G) offered a balanced approach to efficacy and safety.

Conclusions:

• Specific two-layer moderator materials can significantly enhance BNCT performance.
• LiBr-based configurations show potential for maximizing therapeutic dose delivery.
• Al2O3-based configurations are effective in minimizing off-target radiation exposure.
• These findings provide critical data for designing improved beam-shaping assemblies for clinical BNCT.