Performance of a BeO-based dosimetry system for proton and electron beam dose measurements

This study aims to evaluate the performance of the BeO-based myOSLchip system (RadPro International GmbH, Remscheid, Germany) for dosimetry of proton and electron radiotherapy beams. Although beryllium oxide (BeO) has been recognised as a promising material for luminescence dosimetry in radiotherapy, this research extends beyond material properties and examines the entire BeO-based dosimetry system, including the detector, holder, and readout components. Packages of myOSLchip dosimeters were irradiated either in a ( 70-230 ) MeV proton beam or in a 16 MeV electron beam. The readouts were carried out using the portable myOSLchip reader. In the electron beam, tests on the precision, dose response up to 100 Gy and dose-rate effects of the system were carried out. In the proton beam, the system was tested for its dose response (up to 10 Gy), fading, and linear energy transfer (LET) response. For proton irradiations, the myOSLchip BeO OSLDs exhibited stability within 2% over 135 days, as well as a linear dose response in the tested range, (0.1 - 10) Gy. The efficiency showed a reduction for proton beams with LET values (for water) above 0.6 keV/mu m, with up to 40% loss inefficiency at 4 keV/mu m. For the electron irradiations, they showed a linear dose-response up to 20 Gy and dose-rate independence, with a constant response at least up to 2.99 x 105 Gy s-1. Using individual dosimeter sensitivity correction, the precision fora single dosimeter was around 3.5% (standard deviation of the data of all dosimeters) and fora package comprising four dosimeters was 1.7% (standard deviation of the mean of the four dosimeters). These findings suggest the myOSLchip system's potential as a reliable alternative to existing dosimetry systems in clinical applications.