Intracavitary in vivo dosimetry based on multichannel fiber-coupled Radioluminescence and Optically Stimulated Luminescence of Al$_2$O$_3$ :C
Résumé
Fiber Optic Dosimetric Catheters (FODCs) composed of chains of alumina crystals are investigated by the CEA LIST within the French ANR-INTRADOSE Project in the purpose of intracavitary in vivo dosimetry (IVD) during Brachytherapy (BT) with iridium sources and Intensity-Modulated Radiation Therapy (IMRT) with linear accelerators. A dedicated process involving PMMA fibers, casted altogether forming hexagonal bundle, is demonstrated. Optically Stimulated Luminescence (OSL) signals are recorded on-line after irradiation and absorbed doses are compared to planned dose distribution. Real-time dose measurements may also be performed by recording the RadioLuminescence (RL), spontaneously emitted by the crystals during irradiation. In this case, a correction method is implemented to correct for stem effect influence (Cerenkov and scintillation generated within the fibers). For BT, the dual-fiber subtraction method is used (using a reference fiber) whereas the time discrimination method is used for IMRT. The experimental dose distribution leads to an underestimation of the source-sensor distance presumably due to energy dependence of the alumina crystal at low photon energy. At the time being, Monte-Carlo modeling of the FODC is performed with the aim to estimate this energy dependence and finally correct for it. Finally, metrological and preclinical validations are still running at Centre Léon Bérard (Lyon, France) in the purpose of checking the compliance of the FODC prototypes with treatment specifications and medical constraints.
Mots clés
brachytherapy
iridium sources
intensity modulated radiation therapy
IMRT
linear accelerator
hexagonal PMMA fiber bundle
OSL signals
planned dose distribution
real time dose measurements
spontaneously emitted radioluminescence
stem effect influence
Cerenkov radiation
scintillation radiation
dual fiber subtraction method
source-sensor distance
FODC Monte Carlo modeling
Al2O3:C
Photonics
Crystals
Optical fiber cables
Radiation effects
multichannel fiber coupled RL-OSL
intracavitary in vivo dosimetry
optically stimulated luminescence
carbon doped alumina
Optical fiber sensor
Optical fibers
fiber optic dosimetric catheters
alumina crystals
instrumentation
nuclear instrumentation
radiotherapy
ionizing radiation
dosimetry
dose measurement
dose distribution
Distributed and Quasi-distributed sensing
metrology
Monte Carlo
modelling
particle transport
Origine | Accord explicite pour ce dépôt |
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