Radioluminescence results from an Al2O3:C fiber prototype: 6 MV medical beam

Abstract

The Investigations of this article focus on the response of an Al2O3:C radioluminescence (RL) prototype for medical dosimetry in a 6 MV photon beam. The prototype can be configured using two types of detectors coupled to fiber-optic cables - single crystal (1 × 1 × 2 mm3) and droplets (in two grain sizes, 38 and 4 μm, molded in r = 0.5 mm, l = 200 μm). By using the appropriate filters in addition to time gating it is possible to remove disturbance present during irradiation: the stem effect. Pre-irradiation of the dosimeters to a dose of 300 Gy made the memory effects in Al2O3:C negligible, so as to not impair the dosimetric properties of the system. The key findings are that the system is suitable for small field beam dosimetry, while giving overall good dose response in other features (i.e., beam profile, dose rate - FF and FFF modes). The results show that our prototype can be used for real time dose rate assessment in medical photon dosimetry without many correction factors. The 4 μm RL measurement results are in excellent agreement (i.e. below 1%) with the dose delivered according to standard beam data.