A heterogeneous-cavity model for miniaturized detectors of orthovoltage X-rays

Abstract

Abstract To meet the needs of modelling small-sized detectors of orthovoltage X-rays, for spatially fractionated radiotherapy, we propose a model to determine responses of the detectors in cases of highly heterogeneous cavity. The model was applied to a detector whose cavity features a sparse high-Z perovskite scintillation layer embedded in an epoxy resin. Irradiations were carried out using the Small Animal Radiation Research Platform. Local photon and electron spectra were computed by the SpekPy toolbox and Penelope Monte Carlo simulations, respectively. The detector model considers that X-ray photons mainly interact with medium surrounding the scintillation layer, and that the output of the detector mainly results from secondary electrons in this layer. Results from model computations are compared with measurement data, showing differences less than 16% for beam energies in the 60 kVp −220 kVp range.