Multichannel dosemeter and Al2O3:C optically stimulated luminescence fibre sensors for use in radiation therapy: evaluation with electron beams

Abstract

This article proposes an innovative multichannel optically stimulated luminescence (OSL) dosemeter for on-line in vivo dose verification in radiation therapy. OSL fibre sensors incorporating small Al2O3:C fibre crystals (TLD500) have been tested with an X-ray generator. A reproducible readout procedure should reduce the fading-induced uncertainty (∼− 1% per decade). OSL readouts are temperature-dependent [∼0.3% K−1 when OSL stimulation is performed at the same temperature as irradiation; ∼0.16% K−1 after thermalisation (20°C)]. Sensor calibration and depth–dose measurements with electron beams have been performed with a Saturne 43 linear accelerator in reference conditions at CEA-LNHB (ionising radiation reference laboratory in France). Predosed OSL sensors show a good repeatability in multichannel operation and independence versus electron energy in the range (9, 18 MeV). The difference between absorbed doses measured by OSL and an ionisation chamber were within ±0.9% (for a dose of about 1 Gy) despite a sublinear calibration curve.