Speaker
Description
Abstract
Background: FLASH radiotherapy, characterized by ultra-high dose rates (UHDR), has emerged as a promising modality for tumor control with reduced normal tissue toxicity. Dosimetry under UHDR conditions remains challenging due to detector saturation effects, strong dose-rate dependence, and the limited suitability of conventional dosimetric systems. Silicon carbide (SiC) detectors have attracted increasing interest owing to their radiation hardness, fast charge collection, and potential dose-rate independence; nevertheless, their dosimetric response under FLASH irradiation is not yet fully characterized. Comprehensive Monte Carlo (MC) simulations are therefore required to investigate SiC detector behavior and assess their suitability for FLASH-RT applications.
Materials and Methods: Electron FLASH linac (eRT6) geometry model within the GEANT4 simulation framework. The temporal beam structure, including pulse width, pulse shape (square and Gaussian), and repetition frequency, was explicitly implemented in eRT6 model. A SiC detector array was modeled with realistic geometry and material properties and placed at various orientations within a voxelated water phantom.
Results: Dose profile distributions measured by the SiC detector array were compared with those obtained in the water phantom, showing good agreement. Time-resolved detector response was obtained by post-processing the simulation output using dedicated Python-ROOT analysis scripts. Whereas, time-resolved readout successfully captured the temporal structure of the pulsed eRT6 beam, with the pulse shape generated at the source clearly captured by the 40-SiC detector array.
Conclusion: The implementation of the beam structure enabled an accurate reproduction of pulsed irradiation conditions, and the simulated SiC detector response showed good agreement with the dose distributions in a water phantom. The developed framework therefore provides a validated basis for further characterization of SiC detector performance under UHDR conditions. Ongoing analyses focus on assessing the influence of detector characteristics, such as active area and material density, as well as beam structure parameters, including dose per pulse and repetition rate.