Journal article
Stem signal suppression in fiber-coupled Al2O3:C dosimetry for 192Ir brachytherapy
Radiation Physics, Radiation Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark1
Radiation Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark2
Risø National Laboratory for Sustainable Energy, Technical University of Denmark3
Copenhagen University Hospital Herlev and Gentofte4
Aarhus University5
The stem signal, composed of fluorescence and Čerenkov light, becomes a significant source of uncertainty in fiber-coupled afterloaded brachytherapy dosimetry when the source dwells near the fiber cable but far from the detector. A stem suppression technique originally developed for scintillators was adapted for on-line in-vivo dosimetry using fiber-coupled carbon doped aluminum oxide (Al2O3:C).
The technique involved a two-channel optical filtration of the radioluminescence (RL) emitted from a pre-irradiated Al2O3:C crystal with enhanced sensitivity. The system responded linearly in the absorbed dose range 0.05–50 Gy, as needed under high dose rate (HDR) conditions. The dosimeter was irradiated in a water phantom using a 37 GBq 192Ir source at source-to-crystal distances ranging from 0.5 cm to 6.7 cm.
For irradiation conditions that generated a stem component in the range 4%–15% in the unfiltered signal, and up to 5 ± 1% in a single-channel read-out optimized for Al2O3:C, the adapted stem suppression technique reduced the stem component to −1 ± 3%. The stem suppressed dosimeter response and the 192Ir source depth dose curve agreed within position uncertainties, and with a 5% maximum deviation, for distances up to 6 cm.
Language: | English |
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Year: | 2011 |
Pages: | 2020-2024 |
ISSN: | 18790925 and 13504487 |
Types: | Journal article |
DOI: | 10.1016/j.radmeas.2011.05.079 |
ORCIDs: | Andersen, Claus Erik |
Al2O3:C Background suppression Brachytherapy dosimetry Dose-rate brachytherapy Ir-192 Luminescence dosimetry Nuclear Radiation Stem signal Strålingsfysik System