The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
E. Lewis - One of the best experts on this subject based on the ideXlab platform.
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Investigation of YAG:Ce-Based Optical Fibre Sensor for Use in Ultra-Fast External Beam Radiotherapy Dosimetry
Journal of Lightwave Technology, 2019Co-Authors: Lingxia Chen, Peter Woulfe, Sinead O'Keeffe, Shuilin Chen, Sean Gillespie, Benxue Jiang, E. LewisAbstract:Radiation dosimetry plays a crucial role in the quality assurance in radiotherapy. To date, this is limited to monitoring the overall dose over the complete beam time, and so, there is limited information on the actual beam quality. An optical fibre sensor is developed based on cerium-doped yttrium aluminum garnet (YAG:Ce) scintillator. The temporal resolution and the stability of this scintillator-based optical fibre sensor have been experimentally evaluated and directly compared with similarly fabricated sensors based on terbium activated Gadolinium Oxysulfide and commercial plastic scintillating fibre, BCF-12. The photon yield and repeatability of the YAG-based sensor are compared in the clinical setting with the BCF-12 sensor and both show a high stability. The coefficient of variation of the YAG sensor is 0.7%, which is lower than the BCF sensor with a coefficient of variation of 1.4%.
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Investigation of YAG:Ce Based Optical Fibre Sensor for Use in External Beam Radiotherapy Dosimetry
26th International Conference on Optical Fiber Sensors, 2018Co-Authors: Lingxia Chen, Peter Woulfe, E. Lewis, Shuilin Chen, Sean Gillespie, Benxue Jiang, Charusluk Viphavakit, Sinead O'KeeffeAbstract:The main focus of this study is the evaluation of Cerium doped yttrium aluminium garnet (YAG:Ce) scintillator for its suitability for in vivo dosimetry during radiotherapy. An optical fibre sensor has been developed based on YAG:Ce and is compared with similarly fabricated sensors using Terbium activated Gadolinium Oxysulfide (GOS) and plastic scintillating fibre, BCF-12. The YAG:Ce based optical fibre sensor has a fast decay time (70 ns) and lower afterglow allowing it to accurately discern the individual micro-pulses and recovers quickly between pulses, which is not possible with the GOS based sensor. The photon yield and repeatability of the YAG sensor and is compared with the BCF-12 sensor. The YAG sensor provides a stable output signal, 12 times higher than that observed with the BCF-12 sensor, with a coefficient of variation of 0.7 %, which is lower than the BCF sensor (1.4 %).
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A novel structure optical fiber radiation dosimeter for radiotherapy applications
Proceedings of SPIE, 2016Co-Authors: Yu Ma, Wenhui Zhao, Daxin Zhang, Ziyin Chen, Yaosheng Hu, E. LewisAbstract:An investigation into a novel in-vivo PMMA (polymethyl methacrylate) fiber-optic dosimeter to monitor the dose of ionizing radiation, both for instantaneous and integrating measurements, for radiotherapy applications is proposed. This fiber sensor is designed as an intracorporal X-ray ionizing sensor to enhance the curative effect of radiotherapy. The fiber-optic dosimeter is made in a PMMA fiber, whose core is micromachined to create a small diameter (0.25 to 0.5 mm) hole at one fiber end. An inorganic scintillating material, terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb) is chosen as the sensing material, because it can fluoresce on immediately under exposure of ionizing radiation (X-Rays or electron beam). This sensing material is filled and packaged in the small hole by epoxy resin adhesive. This kind of novel structure dosimeter shows high light coupling efficiency compared with other kind of inorganic scintillation dosimeter. This fiber-optic dosimeter shows good repeatability with a maximum deviation of 0.16%. The testing results of the fiber-optic dosimeter are perfectly proportional to the data of IC with R2 as 0.9999. In addition, the fiber sensor shows excellent isotropic in its radial angular dependence. All the experiments indicate that the fiber-optic dosimeter is properly used for patient in-vivo dosimeter such as brachytherapy applications or intraoperative radiation therapy.
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A PMMA Optical Fibre Sensor for Clinic Radiotherapy Real-Time Monitoring Application
2015 Fifth International Conference on Instrumentation and Measurement Computer Communication and Control (IMCCC), 2015Co-Authors: Wenhui Zhao, Daxin Zhang, Ziyin Chen, E. LewisAbstract:A PMMA optical fibre sensor for real-time monitoring of radiotherapy dosimetry is presented. The sensor is based on a X-Ray sensitive scintillating material filled into the micro hole located at one end of the fibre. The scintillating material terbium-doped Gadolinium Oxysulfide (Gd2O2S: Tb) fluoresces under the X-Ray beam delivered with a range of dose rate from 100MU/min to 600MU/min, and the signal intensity delivered using OFS shows great linearity with the detector background noise removed. The results represent an excellent linear relationship (R2 of 1) between the output intensity using OFS and the simultaneous measurements of dose which was simultaneously measured and verified using an Ionsitation Chamber IC, demonstrating the potential of the novel OFS for use in radiotherapy dosimetry applications.
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Terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillation-based polymer optical fibre sensor for real time monitoring of radiation dose in oncology
Optical Sensing and Detection III, 2014Co-Authors: E. Lewis, Peter Woulfe, Sinead O'Keeffe, M. Grattan, A. Hounsell, J. Cronin, D. Mccarthy, Dan Sporea, Laura Mihai, Arvind SanthanamAbstract:A PMMA based plastic optical fibre sensor for use in real time radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb), which fluoresces when exposed to ionising radiation (X-Ray). The emitted visible light signal penetrates the sensor optical fibre and propagates along the transmitting fibre at the end of which it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.5% and the response is independent of dose rate.
Sinead O'Keeffe - One of the best experts on this subject based on the ideXlab platform.
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Investigation of YAG:Ce-Based Optical Fibre Sensor for Use in Ultra-Fast External Beam Radiotherapy Dosimetry
Journal of Lightwave Technology, 2019Co-Authors: Lingxia Chen, Peter Woulfe, Sinead O'Keeffe, Shuilin Chen, Sean Gillespie, Benxue Jiang, E. LewisAbstract:Radiation dosimetry plays a crucial role in the quality assurance in radiotherapy. To date, this is limited to monitoring the overall dose over the complete beam time, and so, there is limited information on the actual beam quality. An optical fibre sensor is developed based on cerium-doped yttrium aluminum garnet (YAG:Ce) scintillator. The temporal resolution and the stability of this scintillator-based optical fibre sensor have been experimentally evaluated and directly compared with similarly fabricated sensors based on terbium activated Gadolinium Oxysulfide and commercial plastic scintillating fibre, BCF-12. The photon yield and repeatability of the YAG-based sensor are compared in the clinical setting with the BCF-12 sensor and both show a high stability. The coefficient of variation of the YAG sensor is 0.7%, which is lower than the BCF sensor with a coefficient of variation of 1.4%.
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Investigation of YAG:Ce Based Optical Fibre Sensor for Use in External Beam Radiotherapy Dosimetry
26th International Conference on Optical Fiber Sensors, 2018Co-Authors: Lingxia Chen, Peter Woulfe, E. Lewis, Shuilin Chen, Sean Gillespie, Benxue Jiang, Charusluk Viphavakit, Sinead O'KeeffeAbstract:The main focus of this study is the evaluation of Cerium doped yttrium aluminium garnet (YAG:Ce) scintillator for its suitability for in vivo dosimetry during radiotherapy. An optical fibre sensor has been developed based on YAG:Ce and is compared with similarly fabricated sensors using Terbium activated Gadolinium Oxysulfide (GOS) and plastic scintillating fibre, BCF-12. The YAG:Ce based optical fibre sensor has a fast decay time (70 ns) and lower afterglow allowing it to accurately discern the individual micro-pulses and recovers quickly between pulses, which is not possible with the GOS based sensor. The photon yield and repeatability of the YAG sensor and is compared with the BCF-12 sensor. The YAG sensor provides a stable output signal, 12 times higher than that observed with the BCF-12 sensor, with a coefficient of variation of 0.7 %, which is lower than the BCF sensor (1.4 %).
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A Novel Plastic Optical Fibre-Based Scintillator Detector's Response in Neutron Irradiation up to 400 MeV
2018 IEEE SENSORS, 2018Co-Authors: C. Penner, Sinead O'Keeffe, C. Duzenli, Boris Stoeber, C. HoehrAbstract:A study was carried out to determine if a novel, millimeter sized Terbium-activated Gadolinium Oxysulfide optical fibre detector can detect neutrons from a 0×400 MeV neutron beam. Two different sensor samples with different distributions of scintillator powder were tested. Both responded to the neutron irradiation. The denser sample was then explored to measure the vertical profile of the neutron beam. This demonstrates that the sensor can be used to detect neutrons.
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Terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillation-based polymer optical fibre sensor for real time monitoring of radiation dose in oncology
Optical Sensing and Detection III, 2014Co-Authors: E. Lewis, Peter Woulfe, Sinead O'Keeffe, M. Grattan, A. Hounsell, J. Cronin, D. Mccarthy, Dan Sporea, Laura Mihai, Arvind SanthanamAbstract:A PMMA based plastic optical fibre sensor for use in real time radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb), which fluoresces when exposed to ionising radiation (X-Ray). The emitted visible light signal penetrates the sensor optical fibre and propagates along the transmitting fibre at the end of which it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.5% and the response is independent of dose rate.
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Optical Fibre Luminescence Sensor for Real-time Radiotherapy Dosimetry
Imaging and Applied Optics, 2013Co-Authors: Sinead O'Keeffe, Peter Woulfe, J. Cronin, Arvind Santhanam, D. Mccarthy, N. Agazaryan, E. LewisAbstract:A plastic optical fibre, coated with a terbium-doped Gadolinium Oxysulfide phosphor (Gd2O2S:Tb) is presented. The paper presents the sensor's response to a range of known radiotherapy exposure patterns and characterises its response to varying energy levels and dose rates.
Peter Woulfe - One of the best experts on this subject based on the ideXlab platform.
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Investigation of YAG:Ce-Based Optical Fibre Sensor for Use in Ultra-Fast External Beam Radiotherapy Dosimetry
Journal of Lightwave Technology, 2019Co-Authors: Lingxia Chen, Peter Woulfe, Sinead O'Keeffe, Shuilin Chen, Sean Gillespie, Benxue Jiang, E. LewisAbstract:Radiation dosimetry plays a crucial role in the quality assurance in radiotherapy. To date, this is limited to monitoring the overall dose over the complete beam time, and so, there is limited information on the actual beam quality. An optical fibre sensor is developed based on cerium-doped yttrium aluminum garnet (YAG:Ce) scintillator. The temporal resolution and the stability of this scintillator-based optical fibre sensor have been experimentally evaluated and directly compared with similarly fabricated sensors based on terbium activated Gadolinium Oxysulfide and commercial plastic scintillating fibre, BCF-12. The photon yield and repeatability of the YAG-based sensor are compared in the clinical setting with the BCF-12 sensor and both show a high stability. The coefficient of variation of the YAG sensor is 0.7%, which is lower than the BCF sensor with a coefficient of variation of 1.4%.
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Investigation of YAG:Ce Based Optical Fibre Sensor for Use in External Beam Radiotherapy Dosimetry
26th International Conference on Optical Fiber Sensors, 2018Co-Authors: Lingxia Chen, Peter Woulfe, E. Lewis, Shuilin Chen, Sean Gillespie, Benxue Jiang, Charusluk Viphavakit, Sinead O'KeeffeAbstract:The main focus of this study is the evaluation of Cerium doped yttrium aluminium garnet (YAG:Ce) scintillator for its suitability for in vivo dosimetry during radiotherapy. An optical fibre sensor has been developed based on YAG:Ce and is compared with similarly fabricated sensors using Terbium activated Gadolinium Oxysulfide (GOS) and plastic scintillating fibre, BCF-12. The YAG:Ce based optical fibre sensor has a fast decay time (70 ns) and lower afterglow allowing it to accurately discern the individual micro-pulses and recovers quickly between pulses, which is not possible with the GOS based sensor. The photon yield and repeatability of the YAG sensor and is compared with the BCF-12 sensor. The YAG sensor provides a stable output signal, 12 times higher than that observed with the BCF-12 sensor, with a coefficient of variation of 0.7 %, which is lower than the BCF sensor (1.4 %).
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Characterization of a Terbium-Activated Gadolinium Oxysulfide Plastic Optical Fiber Sensor in Photons and Protons
IEEE Sensors Journal, 2018Co-Authors: C. Penner, Peter Woulfe, C. Hoehr, Sinead O’keeffe, C. DuzenliAbstract:A characterization study was carried out to determine if a novel, millimeter sized Terbium-activated Gadolinium Oxysulfide optical fibre detector has potential for future use in proton dosimetry. Preliminary studies employed a Theratronics Theratron 780C Cobalt-60 unit and were used to determine nominal dose response, field size response and Čerenkov contributions in 1.25-MeV gamma radiation. More extensive testing was done using 74 MeV-protons produced in the TRIUMF 500-MeV cyclotron facility examining raw Bragg peak, spread out Bragg peak, dose response, and Čerenkov signal. The detector was low-cost and easily assembled; it showed excellent sensitivity, signal to noise ratio, and reproducibility. Quenching at high linear energy transfer was severe. Additional investigations are needed to further explore Čerenkov-only depth-dose curves, signal detection at the extreme distal end of the Bragg peak, and possible sensitivity to neutrons.
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Terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillation-based polymer optical fibre sensor for real time monitoring of radiation dose in oncology
Optical Sensing and Detection III, 2014Co-Authors: E. Lewis, Peter Woulfe, Sinead O'Keeffe, M. Grattan, A. Hounsell, J. Cronin, D. Mccarthy, Dan Sporea, Laura Mihai, Arvind SanthanamAbstract:A PMMA based plastic optical fibre sensor for use in real time radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped Gadolinium Oxysulfide (Gd2O2S:Tb), which fluoresces when exposed to ionising radiation (X-Ray). The emitted visible light signal penetrates the sensor optical fibre and propagates along the transmitting fibre at the end of which it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.5% and the response is independent of dose rate.
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Optical Fibre Luminescence Sensor for Real-time Radiotherapy Dosimetry
Imaging and Applied Optics, 2013Co-Authors: Sinead O'Keeffe, Peter Woulfe, J. Cronin, Arvind Santhanam, D. Mccarthy, N. Agazaryan, E. LewisAbstract:A plastic optical fibre, coated with a terbium-doped Gadolinium Oxysulfide phosphor (Gd2O2S:Tb) is presented. The paper presents the sensor's response to a range of known radiotherapy exposure patterns and characterises its response to varying energy levels and dose rates.
Gabriela Palestino - One of the best experts on this subject based on the ideXlab platform.
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Eu3+/Yb3+ co-doped Gadolinium Oxysulfide upconverting nanorods: Morphological, physicochemical and optical evaluation
Journal of Alloys and Compounds, 2019Co-Authors: César Del Angel-olarte, Luis Hernandez-adame, Antonio Méndez-blas, Gabriela PalestinoAbstract:Abstract In this study, we introduce a novel route to produce down and upconverting Eu3+/Yb3+ co-doped Oxysulfide nanorods, which display strong red emission at 620 nm under Vis (460 nm) or NIR (976 nm) wavelength excitation. An in-depth analysis of the synthesis parameters such as lanthanides concentration, type of nucleating agent, reaction temperature, and the reaction pressure was performed to determine their influence in the morphology and photoluminescence properties. It was demonstrated that as a nucleating agent, ethanolamine is a good substitute of the commonly used triethylamine providing the advantage of using lower toxicity reagents. The Transmission Electron Microscopy (TEM), Infrared (FTIR) and Zeta Potential analysis showed that the chemical surface of nanorods evolve during thermal and sulfidation processes without producing morphological changes. The intensity of light emission during downconversion (DC) and upconversion (UC) phenomena was found to be doping ions concentration dependent. The highest DC light emission was found at a Yb3+/Eu3+ concentration ratio of 0.25, while the most intense UC luminescence was found at 4. Conversely, quenching of DC and UC was observed when using Yb3+/Eu3+ concentration ratios of 4 and 0.25 respectively, indicating that luminescent centers are strongly affected in both processes by the chemical environment but also for the ions doping ratio. It was demonstrated that two-photon absorption is the primary mechanism for the red emission in the UC process.
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eu3 yb3 co doped Gadolinium Oxysulfide upconverting nanorods morphological physicochemical and optical evaluation
Journal of Alloys and Compounds, 2019Co-Authors: Cesar Del Angelolarte, Luis Hernandezadame, Antonio Mendezblas, Gabriela PalestinoAbstract:Abstract In this study, we introduce a novel route to produce down and upconverting Eu3+/Yb3+ co-doped Oxysulfide nanorods, which display strong red emission at 620 nm under Vis (460 nm) or NIR (976 nm) wavelength excitation. An in-depth analysis of the synthesis parameters such as lanthanides concentration, type of nucleating agent, reaction temperature, and the reaction pressure was performed to determine their influence in the morphology and photoluminescence properties. It was demonstrated that as a nucleating agent, ethanolamine is a good substitute of the commonly used triethylamine providing the advantage of using lower toxicity reagents. The Transmission Electron Microscopy (TEM), Infrared (FTIR) and Zeta Potential analysis showed that the chemical surface of nanorods evolve during thermal and sulfidation processes without producing morphological changes. The intensity of light emission during downconversion (DC) and upconversion (UC) phenomena was found to be doping ions concentration dependent. The highest DC light emission was found at a Yb3+/Eu3+ concentration ratio of 0.25, while the most intense UC luminescence was found at 4. Conversely, quenching of DC and UC was observed when using Yb3+/Eu3+ concentration ratios of 4 and 0.25 respectively, indicating that luminescent centers are strongly affected in both processes by the chemical environment but also for the ions doping ratio. It was demonstrated that two-photon absorption is the primary mechanism for the red emission in the UC process.
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effect of tb3 concentration in the visible emission of terbium doped Gadolinium Oxysulfide microspheres
Solid State Sciences, 2018Co-Authors: Luis Hernandezadame, Gabriela Palestino, O Meza, Pablo Luis Hernandezadame, Hector Rene Vegacarrillo, Iyad SarhidAbstract:Abstract Experimental data obtained from optical characterization of Gd2O2S:Tb3+ microspheres were compared with a rate-equation model in order to understand and simulate the emission intensity and color tonality as a function of Tb3+ concentration. The microparticles were prepared by hydrothermal synthesis and characterized by TEM and XRD to confirm spherical microparticles with a hexagonal lattice. Furthermore, fluorescent spectroscopy and rate equation model revealed that the direct energy transfer between Gd3+→Tb3+ ions and the migration of the excitation energy between Tb3+ play an important role in the luminescence intensity, while the color tonality is mainly governed by the non-radiative relaxation processes between Tb3+ at low concentrations. Finally, our results suggest that the rate equation model provides an efficient alternative to estimate theoretically the maximum doping concentration in Oxysulfides before they present quenching of luminescence.
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Synthesis, characterization, and photoluminescence properties of Gd:Tb Oxysulfide colloidal particles
Chemical Engineering Journal, 2014Co-Authors: Luis Hernandez-adame, Francisco J. Medellín-rodríguez, Antonio Méndez-blas, Jaime Ruiz-garcia, J. Roger Vega-acosta, Gabriela PalestinoAbstract:Abstract Terbium-doped Gadolinium Oxysulfide (Gd 2 O 2 S:Tb 3+ ) nanoparticles were synthesized by using a hydrothermal method followed with a sulfur reaction. We studied parameters such as precursor concentration, stock solutions temperature, reaction time, and reaction temperature to obtain well defined homogeneous particles with specific shape and size. The chemical evolution of the formed particles was followed by the Infrared Spectroscopy (FTIR), thus showing the removal of the hydroxycarbonate precursors at different stages of synthesis. X-ray analysis (WAXD) confirmed that the calcination and sulfidation processes produced cubic (Gd 2 O 3 :Tb 3+ ) and hexagonal (Gd 2 O 2 S:Tb 3+ ) crystalline structures. The photoluminescent (PL) properties were evaluated as a response to UV light excitation in both solid phase and colloidal suspension; we determine the maximum emission intensity as a function of the Tb 3+ ion dopant concentration and determine the limiting amount in the material before quenching occurs. In colloidal suspensions, the emission spectra of both Gd 2 O 3 :Tb 3+ and Gd 2 O 2 S:Tb 3+ were compared, and we observed that the sulfidation process increased the integrated emission intensity seventyfold with respect to the former. To evaluate the particles behavior in aqueous media for possible uses in medical applications, an electrophoretic mobility study was carried out, thus observing that the fluorescence emission depends on the pH of the solution, which in turn correlates with the electrophoretic mobility of the particles.
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Synthesis of Gd2O2S:Tb nanoparticles and optical characterization
Proceedings of SPIE, 2013Co-Authors: Luis Hernandez-adame, Francisco J. Medellín-rodríguez, Antonio Méndez-blas, R. Vega-acosta, Gabriela PalestinoAbstract:Terbium-doped Gadolinium Oxysulfide (Gd 2 O 2 S:Tb) nanoparticles were synthesized by hydrothermal precipitation of urea. On the reaction, were analyzed variables as the temperature of solutions, the reaction time and the stirring velocities as main factors in the crystal growth. WAXD TEM and FTIR analysis were used to characterize the Crystallographic phase, morphology and chemical vibrations of the materials. Moreover, the photoluminescent properties were evaluated as response at the UV light, obtaining the main emission at 544 nm produced by 5 D 4 → 7 F 5 transition of the Tb 3+ ions. Besides, we found that the host lattice and doped-ions concentration is essential to obtain a strong visible photoluminescence evaluated experimentally.
Lingxia Chen - One of the best experts on this subject based on the ideXlab platform.
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Investigation of YAG:Ce-Based Optical Fibre Sensor for Use in Ultra-Fast External Beam Radiotherapy Dosimetry
Journal of Lightwave Technology, 2019Co-Authors: Lingxia Chen, Peter Woulfe, Sinead O'Keeffe, Shuilin Chen, Sean Gillespie, Benxue Jiang, E. LewisAbstract:Radiation dosimetry plays a crucial role in the quality assurance in radiotherapy. To date, this is limited to monitoring the overall dose over the complete beam time, and so, there is limited information on the actual beam quality. An optical fibre sensor is developed based on cerium-doped yttrium aluminum garnet (YAG:Ce) scintillator. The temporal resolution and the stability of this scintillator-based optical fibre sensor have been experimentally evaluated and directly compared with similarly fabricated sensors based on terbium activated Gadolinium Oxysulfide and commercial plastic scintillating fibre, BCF-12. The photon yield and repeatability of the YAG-based sensor are compared in the clinical setting with the BCF-12 sensor and both show a high stability. The coefficient of variation of the YAG sensor is 0.7%, which is lower than the BCF sensor with a coefficient of variation of 1.4%.
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Investigation of YAG:Ce Based Optical Fibre Sensor for Use in External Beam Radiotherapy Dosimetry
26th International Conference on Optical Fiber Sensors, 2018Co-Authors: Lingxia Chen, Peter Woulfe, E. Lewis, Shuilin Chen, Sean Gillespie, Benxue Jiang, Charusluk Viphavakit, Sinead O'KeeffeAbstract:The main focus of this study is the evaluation of Cerium doped yttrium aluminium garnet (YAG:Ce) scintillator for its suitability for in vivo dosimetry during radiotherapy. An optical fibre sensor has been developed based on YAG:Ce and is compared with similarly fabricated sensors using Terbium activated Gadolinium Oxysulfide (GOS) and plastic scintillating fibre, BCF-12. The YAG:Ce based optical fibre sensor has a fast decay time (70 ns) and lower afterglow allowing it to accurately discern the individual micro-pulses and recovers quickly between pulses, which is not possible with the GOS based sensor. The photon yield and repeatability of the YAG sensor and is compared with the BCF-12 sensor. The YAG sensor provides a stable output signal, 12 times higher than that observed with the BCF-12 sensor, with a coefficient of variation of 0.7 %, which is lower than the BCF sensor (1.4 %).
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Highly Sensitive Extrinsic X-Ray Polymer Optical Fiber Sensors Based on Fiber Tip Modification
IEEE Sensors Journal, 2017Co-Authors: Ana I. De Andrés, Sinead O’keeffe, Lingxia Chen, Óscar EstebanAbstract:An extrinsic X-ray fiber sensor with improved sensitivity is presented. The developed device is based on an inorganic scintillator (terbium-doped Gadolinium Oxysulfide) attached to a polymer fiber tip. Sensitivity improvement has been accomplished by modifying the fiber tip in two ways: by thermomechanical tapering and by chemical etching. Thus, the useful surface in contact with the scintillator increases, and so the fluorescence light gathering capability. All the fabricated devices have been tested under X-ray irradiation from a Linac at a dose rate of 300 monitor units/min, with a readout every 100 ms. The obtained results shown a signal improvement of up to 43 times when compared with previous reported proposals using inorganic scintillators and polymer fibers. Moreover, the recorded signal under the same measurement conditions can be further improved if the inorganic scintillator is used in powder format instead into an epoxy matrix.
