Monte Carlo simulation of dose distributions from a synchrotron-produced microplanar beam array using the EGS4 code...

Area of Science:

• Medical Physics
• Radiation Oncology
• Monte Carlo Simulations

Background:

• Microbeam radiation therapy (MRT) is a promising technique for brain tumor treatment.
• Accurate simulation of synchrotron-based X-ray microbeams is crucial for optimizing MRT parameters.
• Existing simulation tools required adaptation for precise low-energy X-ray transport and synchrotron characteristics.

Purpose of the Study:

• To develop and validate a novel Monte Carlo simulation code for calculating microbeam radiation dose profiles.
• To accurately model synchrotron X-ray properties, including polarization, spectrum, and beam penumbra.
• To investigate the efficacy of microbeam array configurations for brain tumor treatment.

Main Methods:

• Adapted the LSCAT (Low energy SCATtering) package within the EGS4 Monte Carlo code.
• Developed a custom user code to simulate synchrotron X-ray microbeam properties with 1-micrometer precision.
• Utilized a two-concentric-sphere phantom (brain and skull) and tested various microbeam array configurations.

Main Results:

• The simulation accurately calculated microbeam radiation dose profiles, validated by experimental measurements.
• Simulated microbeam arrays demonstrated adequate peak-to-valley dose ratios (≥5:1) at relevant therapeutic depths.
• The code successfully incorporated synchrotron X-ray characteristics like polarization and spectral distribution.

Conclusions:

• The developed user code provides a precise tool for simulating synchrotron-based microbeam radiation therapy.
• Optimized microbeam parameters show potential for effective brain tumor treatment with improved dose conformity.
• Further research can leverage these simulations to refine MRT protocols and enhance treatment planning.