HetMS-MC: A framework for heterogeneous multiscale Monte Carlo modelling in radiation medicine

Area of Science:

• Radiation physics
• Computational modeling
• Medical physics

Background:

• Radiation medicine requires understanding processes across multiple length scales.
• Multiscale modeling is crucial for advancing treatments like gold nanoparticle-enhanced radiation therapy (GNPT).
• Previous multiscale modeling efforts lacked standardization and a unified framework.

Purpose of the Study:

• To introduce a standardized framework for heterogeneous multiscale Monte Carlo (HetMS-MC) modeling in radiation medicine.
• To provide a structured approach for creating and analyzing HetMS-MC models.

Main Methods:

• Developed a framework encompassing model creation, simulation setup, and uncertainty analysis.
• Demonstrated the framework using two examples: a tumor model and a GNPT scenario.
• Implemented models in EGSnrc, simulating cm-scale tumors with micron-scale cells to score specific energy.

Main Results:

• The tumor model highlighted the necessity of multiscale modeling by revealing variations in specific energy distributions not apparent in conventional simulations.
• The GNPT model underscored the significance of multi-scale bridging in HetMS-MC model development.
• HetMS-MC models captured parameter-dependent energy distribution differences influenced by cell arrangement and random number seeds.

Conclusions:

• A general HetMS-MC framework has been established for radiation medicine applications.
• The framework facilitates efficient simulation of radiation physics across length scales for diverse treatment modalities.
• This approach supports the development of advanced radiation therapies by enabling comprehensive multiscale analysis.