Multichannel dosemeter and Al2O3:C optically stimulated luminescence fibre sensors for use in radiation therapy: evaluation with electron beams
Résumé
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 Al2 O3 :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 pm 0.9% (for a dose of about 1 Gy) despite a sublinear calibration curve.
Mots clés
OSL fibre sensor
instrumentation
Optical Fiber Sensor
temperature
thermalisation
Sensor
calibration
calibration curve
Saturne 43 linear accelerator
Distributed and Quasi-distributed sensing
repeatability
radiation therapy
multichannel operation
X-rays
radiotherapy
dose verification
dosimetry
dose measurement
optically stimulated luminescence dosemeter
ionizing radiation
absorbed dose
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