Characterization of a Terbium-Activated Gadolinium Oxysulfide Plastic Optical Fiber Sensor in Photons and Protons

Penner, Crystal; Hoehr, Cornelia; O'Keeffe, Sinéad; Woulfe, Peter; Duzenli, Cheryl

doi:10.1109/jsen.2017.2780163

Cited by 23 publications

(11 citation statements)

References 20 publications

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“…However, the percentage differences between the OFS and the microdiamond and the W1 decreased with a decrease in field size from 17.4 ± 0.04%, 8.3 ± 0.04% and 5.4 ± 0.06% for 10x10 cm 2 , 4x4 cm 2 and 2x2 cm 2 , respectively. As the Gd2O2S:Tb scintillator is not a water equivalent material (Zeff = 64), the scattered radiation produced when the field sizes and/or the depth in phantom increases plays an important role in the overresponse of the OFS [15,19,20] When compared to other studies that employed scintillating material with high Z numbers, however, our results showed higher discrepancies across the investigated field sizes [15,20].This can be partly attributed to the Cerenkov radiation produced in the fibre itself and in the solid water phantom [21]. A 5% difference was reported by Martinez et al (2015) for their YVO4:Eu 3+ sensor when measuring PDD for a 3x3 cm 2 radiation field size with and without temporal filtration of Cerenkov at 10 cm depth [19].…”

Section: Percentage Depth Dose and Lateral Dose Measurementscontrasting

confidence: 61%

Dosimetric Characterization of an Inorganic Optical Fiber Sensor for External Beam Radiation Therapy

et al. 2019

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The aim of this study was to investigate the dosimetric performance of a novel optical fiber sensor for use in external beam radiation therapy. Repeatability and reproducibility of the output signal, linearity, dose rate and dose per pulse dependence were evaluated. Angular dependence was investigated in the axial and azimuthal planes. The percentage depth dose and lateral dose profiles were measured using the optical fiber sensor system and compared to commercially available detectors such as Exradin W1 plastic scintillator and a PTW-microdiamond detector. The result of this study show that the optical fiber sensor system has good repeatability and reproducibility of the output signal with a maximum deviation of 0.17% and 1.00%, respectively. The system also showed an excellent linearity with dose, and its signal was independent of dose rate. However, the system showed a strong dependence on dose per pulse with 27% deviation from the W1 result at the highest dose per pulse value that was achieved at 75 cm source to surface distance. The system also showed an angular dependence when the incident beam was in the azimuthal plane due to the geometry of the scintillator at the tip of the fiber. The optical fiber sensor overresponded when measuring percentage depth dose curves and lateral dose profiles due in part to the sensitivity of the scintillating material (Gd2O2S:Tb) to low energy scattered radiation. However, further investigation is needed to quantify the overall contribution of Cerenkov radiation to the over-response of the optical fiber sensor.

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Section: Percentage Depth Dose and Lateral Dose Measurementscontrasting

confidence: 61%

Dosimetric Characterization of an Inorganic Optical Fiber Sensor for External Beam Radiation Therapy

et al. 2019

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“…Since the linear energy transfer (LET) does change dramatically along the Bragg peak of proton therapy, the independence of both energy and dose rate are crucial characteristics in any new detector. Most scintillation detectors are known to exhibit increased quenching when LET increases 4,6,12–17 due to the participation of alternate modes of energy dissipation in regions of high ionization density. In order to resolve the Bragg peak of the proton dose depth profile, a fiber diameter of 250 m or less may be required 12 .…”

Section: Introductionmentioning

confidence: 99%

Novel Gd3+-doped silica-based optical fiber material for dosimetry in proton therapy

Hoehr

Morana

Duhamel

et al. 2019

Sci Rep

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Optical fibers hold promise for accurate dosimetry in small field proton therapy due to their superior spatial resolution and the lack of significant Cerenkov contamination in proton beams. One known drawback for most scintillation detectors is signal quenching in areas of high linear energy transfer, as is the case in the Bragg peak region of a proton beam. In this study, we investigated the potential of innovative optical fiber bulk materials using the sol-gel technique for dosimetry in proton therapy. This type of glass is made of amorphous silica (SiO) and is doped with Gd ions and possesses very interesting light emission properties with a luminescence band around 314 nm when exposed to protons. The fibers were manufactured at the University of Lille and tested at the TRIUMF Proton Therapy facility with 8.2–62.9 MeV protons and 2–6 nA of extracted beam current. Dose-rate dependence and quenching were measured and compared to other silica-based fibers also made by sol-gel techniques and doped with Ce and Cu. The three fibers present strong luminescence in the UV (Gd) or visible (Cu,Ce) under irradiation, with the emission intensities related directly to the proton flux. In addition, the 0.5 mm diameter Gd-doped fiber shows superior resolution of the Bragg peak, indicating significantly reduced quenching in comparison to the Ce and Cu fibers with a Birks’ constant, k, of (0.0162 0.0003) cm/MeV in comparison to (0.0333 0.0006) cm/MeV and (0.0352 0.0003) cm/MeV, respectively. To our knowledge, this is the first report of such an interesting k for a silica-based optical fiber material, showing clearly that this fiber presents lower quenching than common plastic scintillators. This result demonstrates the high potential of this inorganic fiber material for proton therapy dosimetry.

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“…Except for photon-based RT and BT dosimetry, IOSFDs also demonstrate the potential for dosimetry in other types of therapy treatments such as PT and BNCT [73][74][75][76][77][78][79]. PT offers improved dose distribution compared to ionizing photon radiation.…”

Section: Iosfd For Other Types Of Particle Radiation Dosimetrymentioning

confidence: 99%

“…The IOSFDs reported in this area include a Gd 2 O 2 S:Tb-based detector and a lanthanide-doped silica scintillator-based detector [73][74][75]. Penner et al [73] investigated Gd 2 O 2 S:Tb-based IOSFD for photon and proton dosimetry. For proton dose detection, the detector exhibited excellent sensitivity, signal-to-noise ratio, and reproducibility.…”

Section: Iosfd For Other Types Of Particle Radiation Dosimetrymentioning

confidence: 99%

“…These are due to the ionization-quenching phenomenon resulting from non-radiative de-excitation occurring under conditions of high-density energy deposition [ 80 ]; efforts have been made to find a scintillator with minimized quenching phenomenon. The IOSFDs reported in this area include a Gd 2 O 2 S:Tb-based detector and a lanthanide-doped silica scintillator-based detector [ 73 – 75 ]. Penner et al [ 73 ] investigated Gd 2 O 2 S:Tb-based IOSFD for photon and proton dosimetry.…”

Section: Development Of Iosfdsmentioning

confidence: 99%

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Advances on inorganic scintillator-based optic fiber dosimeters

Ding

Wang³

et al. 2020

EJNMMI Phys

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This article presents a new perspective on the development of inorganic scintillator-based fiber dosimeters (IOSFDs) for medical radiotherapy dosimetry (RTD) focusing on real-time in vivo dosimetry. The scintillator-based optical fiber dosimeters (SFD) are compact, free of electromagnetic interference, radiation-resistant, and robust. They have shown great potential for real-time in vivo RTD. Compared with organic scintillators (OSs), inorganic scintillators (IOSs) have larger X-ray absorption and higher light output. Variable IOSs with maximum emission peaks in the red part of the spectrum offer convenient stem effect removal. This article outlines the main advantages and disadvantages of utilizing IOSs for SFD fabrication. IOSFDs with different configurations are presented, and their use for dosimetry in X-ray RT, brachytherapy (BT), proton therapy (PT), and boron neutron capture therapy (BNCT) is reviewed. Challenges including the percentage depth dose (PDD) deviation from the standard ion chamber (IC) measurement, the angular dependence, and the Cherenkov effect are discussed in detail; methods to overcome these problems are also presented.

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Characterization of a Terbium-Activated Gadolinium Oxysulfide Plastic Optical Fiber Sensor in Photons and Protons

Cited by 23 publications

References 20 publications

Dosimetric Characterization of an Inorganic Optical Fiber Sensor for External Beam Radiation Therapy

Dosimetric Characterization of an Inorganic Optical Fiber Sensor for External Beam Radiation Therapy

Novel Gd3+-doped silica-based optical fiber material for dosimetry in proton therapy

Advances on inorganic scintillator-based optic fiber dosimeters

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