Nanodosimetry-Based Plan Optimization for Particle Therapy.

Area of Science:

• Medical Physics
• Radiation Oncology
• Nanodosimetry

Background:

• Particle therapy treatment planning faces challenges in achieving uniform biological dose response due to uncertainties in physical dose modification.
• Current methods often rely on complex biophysical models, highlighting the need for alternative optimization strategies.

Purpose of the Study:

• To propose and investigate a novel treatment plan optimization strategy for particle therapy based on measurable nanodosimetric quantities.
• To assess the feasibility of achieving uniform biological dose distribution using nanodosimetric descriptors in proton and carbon ion therapy simulations.

Main Methods:

• Simulated simplified proton and carbon ion treatment plans in a water phantom.
• Utilized Geant4-DNA to simulate radiation track structures and calculate nanodosimetric descriptors at various depths.
• Optimized treatment field pencil beam fluences to achieve uniform nanodosimetric descriptors across spread-out particle Bragg peaks.

Main Results:

• A uniform spatial distribution of nanodosimetric descriptors was achievable for both proton and carbon ion plans when optimizing opposing fields.
• Single-field optimization did not yield a uniform distribution of nanodosimetric descriptors.
• The proposed nanodosimetric approach demonstrated potential for creating uniform, and possibly radiobiologically uniform, treatment plans.

Conclusions:

• Nanodosimetry-based optimization offers a promising strategy for achieving uniform biological dose distributions in particle therapy.
• Opposing-field optimization is crucial for realizing uniform nanodosimetric distributions.
• Further research is needed to validate this approach for complex beam arrangements and demonstrate biological uniformity in tumor tissues.