On the use of Al2O3:C and plastic scintillators for small-field dosimetry in MR-linacs

Fiber coupled luminescence detectors based on organic plastic scintillators or inorganic materials such as Al2O3:C are suitable for dosimetry in strong magnetic fields as found in MR-linacs. The main finding of this work was that field-output factor measurements at the maximum dose point are less variable than if measured at the central beam axis (CAX). In contrast to plastic scintillators, Al2O3:C was found to have a yield of radioluminescence per dose that (within uncertainty) is independent of the magnetic field strength.