Scatter factors assessment in microbeam radiation therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Dosimetry

Background:

• Preclinical studies in Microbeam Radiation Therapy (MRT) have advanced to clinical trial preparations.
• Accurate dose determination is critical for the safe and effective implementation of MRT in clinical settings.
• European Synchrotron Radiation Facility's Biomedical Beamline is preparing for clinical trials.

Purpose of the Study:

• To accurately assess scatter factors for Microbeam Radiation Therapy (MRT).
• Scatter factors are essential for translating reference dose measurements to peak doses in MRT.
• To establish reliable methods for dose estimation in upcoming clinical trials.

Main Methods:

• Monte Carlo (MC) simulations using PENELOPE and GEANT4 codes.
• Scatter factors calculated as the ratio of microbeam dose to reference field dose at a specific depth.
• Comparison of MC simulations with experimental data from radiochromic films and a large area chamber.

Main Results:

• MC simulations showed agreement between PENELOPE and GEANT4 for scatter factors.
• Calculated scatter factors reproduced experimental data within uncertainty margins.
• Microbeams (e.g., 50 μm) deposited an average of 30% less dose than reference conditions, highlighting the non-negligible impact of scatter factors.

Conclusions:

• This study provides the first systematic investigation of scatter factors in MRT.
• Scatter factors are crucial for accurate dose delivery in future MRT clinical trials.
• The concordance between MC simulations and experimental results validates the micrometric dose estimation methods.