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Scintillation Properties of Ce3+ Doped Silicon-Magnesium-Aluminum-Lithium Glass Scintillators by using Radiation Sources
摘要： Glass scintillators can be doped with different elements to improve their luminescence properties. In this study, we present 0.5 wt% Ce3+-doped (58?x)SiO2-4MgO-18Al2O3-20Li2O and (58?x)SiO2-4MgO-18Al2O3-20LiF glass scintillators. We used a pulsed laser to measure the laser-induced emission spectrum and the decay time with decreasing temperature from 300 K to 10 K. The light intensity of both glass samples increased with decreasing temperature from 300 K to 10 K. Additionally, the two glass samples exhibited a fast decay time of approximately 25 ns. In the photo-induced spectrum, an excitation peak at 312 nm and two emission peaks, at 370 nm and 700 nm, were observed in both the glass samples. The X-ray-induced emission intensity of former is approximately six times higher than that of latter, and only former glass sample exhibits a proton-induced emission spectrum.
关键词： Luminescence,Decay time,Ce3+,Glass scintillator
更新于2025-11-25 10:30:42
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Characterization of a non-contact imaging scintillator-based dosimetry system for total skin electron therapy
摘要： Surface dosimetry is required for ensuring effective administration of total skin electron therapy (TSET); however, its use is often reduced due to the time consuming and complex nature of acquisition. A new surface dose imaging technique was characterized in this study and found to provide accurate, rapid and remote measurement of surface doses without the need for post-exposure processing. Disc-shaped plastic scintillators (1 mm thick x 15 mm) were chosen as optimal-sized samples and designed to attach to a flat-faced phantom for irradiation using electron beams. Scintillator dosimeter response to radiation damage, dose rate, and temperature were studied. The effect of varying scintillator diameter and thickness on light output was evaluated. Furthermore, the scintillator emission spectra and impact of dosimeter thickness on surface dose were also quantified. Since the scintillators were custom-machined, dosimeter-to-dosimeter variation was tested. Scintillator surface dose measurements were compared to those obtained by optically stimulated luminescence dosimeters (OSLD). Light output from scintillator dosimeters evaluated in this study was insensitive to radiation damage, temperature, and dose rate. Maximum wavelength of emission was found to be 422 nm. Dose reported by scintillators was linearly related to that from OSLDs. Build-up from placement of scintillators and OSLDs had a similar effect on surface dose (3.9% increase). Variation among scintillator dosimeters was found to be 0.3 ± 0.2%. Scintillator light output increased linearly with dosimeter thickness (~1.9×/mm). All dosimeter diameters tested were able to accurately measure surface dose. Scintillator dosimeters can potentially improve surface dosimetry-associated workflow for TSET in the radiation oncology clinic. Since scintillator data output can be automatically recorded to a patient medical record, the chances of human error in reading out and recording surface dose are minimized.
关键词： non-contact,surface dosimetry,optical imaging,scintillator,remote
更新于2025-11-14 15:30:11
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Potential of GAGG:Ce scintillation crystals for synchrotron X-Ray micro-imaging
摘要： We examined the use of cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce) as a material for scintillation screens in synchrotron X-ray radiography (SXR). Highlighted for gamma-ray detection, GAGG:Ce is also an attractive material for SXR because of its high X-ray stopping power and the high light yield at around 530 nm. A thin and transparent screen prepared from our grown ingot of GAGG:Ce was compared with commonly used scintillators of CdWO4 and YAG:Ce in terms of image quality under monochromatic X-ray illumination. Micron spatial resolutions were achieved with comparable image quality, suggesting that a single crystal of GAGG:Ce is competent scintillation material for SXR.
关键词： Spatial resolutions,GAGG,X-ray detection,Synchrotron X-ray radiography,Scintillator
更新于2025-09-23 15:23:52
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Radiation induced luminescence properties of Ce-doped Y2O3-Al2O3-SiO2 glass prepared using floating zone furnace
摘要： We synthesized Y2O3-Al2O3-SiO2 glasses doped with various concentrations of Ce (0, 0.03%, 0.10%, 0.30%, and 1.00%). The glasses were obtained by melt-quenching using an IR mirror furnace, and then they were studied in terms of their optical, dosimetric and scintillation properties. The obtained samples indicated photoluminescence (PL) and scintillation due to the 5d-4f transitions of Ce3+ characterized as a broad emission peaking around 350 nm. The PL and scintillation decay times were 35.4-38.1 ns and 47-109 ns, respectively. The 0.10% Ce-doped sample showed the highest PL quantum yield (20%) among the synthesized samples. The quantum yield was well-correlated with the decay time of PL and scintillation. Thermally- and optically-stimulated luminescence were observed after the irradiation of X-rays (10 Gy). The thermally- and optically-stimulated luminescence spectra were confirmed that the luminescence was due to the 5d-4f transitions of Ce3+ in the 0.03% and 0.10% Ce-doped samples. Overall, the samples showed sensitive response of thermally-stimulated luminescence, and it was the highest for the 0.10% and 0.30% Ce-doped samples, having the dynamic range from 0.01 mGy to 1 Gy.
关键词： Cerium,Scintillator,Dosimeter,Glass
更新于2025-09-23 15:23:52
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Development of simultaneous PET and Compton imaging using GAGG-SiPM based pixel detectors
摘要： Positron emission tomography (PET) is considered an important and powerful tool for molecular imaging and medical diagnosis with its high sensitivity. Further, single-photon emission CT (SPECT) is another important imaging modality providing different types of information in medical diagnosis. On the other hand, Compton imaging is a promising technique for future molecular imaging with multi-nuclides based on Compton scattering kinetics. In this regard, previously, we have developed gadolinium aluminum gallium garnet (GAGG)-scintillation-based PET systems and GAGG-scintillation-based Compton imaging systems for environmental applications. Here, we propose and develop a novel PET–Compton hybrid simultaneous imager based on a two-layer structure using thin scatterers and thick absorbers for multi-nuclide imaging, for e.g., simultaneous imaging of PET and SPECT tracers such as 18F-FDG and 111In, respectively. For achieving good spatial resolution of the Compton imager, the energy resolution of the utilized scintillators forms one of the most important characteristics. In this regard, GAGG is a promising scintillator because of its high light yield of over 50 000 photon/MeV and excellent energy resolution of 4% with no background radiation and moderate decay time. In this study, we present the development of a simultaneous PET–Compton detector that consists of an 8 × 8 multi-pixel photon counter/SiPM (MPPC) array individually coupled with a 2.5 × 2.5 × 9-mm3 Ce:Gd3Ga2.7Al2.3O12 scintillators (absorbers) for proof of concept of simultaneous PET and SPECT imaging. The pixel size of the MPPC is 3 mm × 3 mm, and it is operated at 55 V at room temperature. The signals from the MPPC scintillators are individually amplified and converted with a dynamic time over threshold (dTOT) circuit to record the energy and timing information. In image reconstruction, the data acquired with the use of the developed modules are classified into events of either Compton imaging or PET imaging by coincidence detection between scatterer and absorber or between absorber and absorber, respectively. The coincidence events between absorber and absorber are regarded as PET annihilation-gamma events and those between scatterer and absorber are used as Compton imaging events. In our experiment, images of 111In and 18F-FDG, which are used as multi-nuclide tracers, are acquired simultaneously using the developed detector for Compton imaging and PET imaging. We believe that our approach is a significant step forward for medical imaging and related fields.
关键词： Scintillator,Single-photon emission CT,SiPM,Positron emission tomography,Compton imaging
更新于2025-09-23 15:23:52
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Photoluminescence, scintillation and TSL properties of Eu-doped Al2O3 transparent ceramics synthesized by spark plasma sintering method
摘要： We synthesized Al2O3 transparent ceramics doped with different concentrations of Eu (0.001, 0.01, 0.1 and 1.0%) by the spark plasma sintering (SPS) method, and then we investigated their photoluminescence (PL), scintillation and thermally-stimulated luminescence (TSL) properties. In the PL, the samples showed a broad emission peak at 400 nm due to the 5d-4f transitions of Eu2+ and several sharp emission peaks across 550–750 nm due to the 4f-4f transitions of Eu3+ and the 3d-3d transitions of Cr3+ impurity ion. In addition to these peaks over 550–750 nm, in scintillation, the samples exhibited two broad peaks over 300–400 nm possibly due to not the 5d-4f transitions of Eu2+ but F and F+ centers. In TSL, the glow curve consisted of peaks at approximately 100, 160, 210 and 320 °C. The TSL intensity of the 0.001% Eu-doped sample was the highest, and the TSL response was confirmed to be linear to irradiated X-ray dose in the range from 0.1 to 1000 mGy.
关键词： Transparent ceramic,Scintillator,Eu,Dosimeter,Al2O3
更新于2025-09-23 15:23:52
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Novel scintillating nanocomposite for X-ray induced photodynamic therapy
摘要： We synthesize a novel prospective nanocomposite material for X-ray induced photodynamic therapy. ZnO:Ga core is coated by the SiO2 shell facilitating a functionalization by a photosensitizer, protoporphyrin PpIX layer. By steady-state and time resolved spectroscopy we confirm the presence of energy transfer between the core and the photosensitizer, an essential requirement to induce a cytotoxic effect. Using the commercial chemical probe we also demonstrate the ability of prepared ZnO:Ga@SiO2-PpIX nanocomposite to generate singlet oxygen. Presented results show that this nanocomposite can be considered as a good candidate for potential application in X-ray induced photodynamic therapy.
关键词： Scintillator,Nanocomposite,Zinc oxide,Photodynamic therapy,Singlet oxygen
更新于2025-09-23 15:23:52
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Characterizing a novel scintillating glass for application to megavoltage cone-beam computed tomography
摘要： Purpose: The purpose of the present study was to evaluate the performance of a prototype electric portal imaging device (EPID) with a high detective quantum efficiency (DQE) scintillator, LKH-5. Specifically, image quality in context of both planar and megavoltage (MV) cone-beam computed tomography (CBCT) is analyzed. Methods: Planar image quality in terms of modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) are measured and compared to an existing EPID (AS-1200) using the 6 MV beamline for a Varian TrueBeam linac. Imager performance is contextualized for three-dimensional (3D), MV-CBCT performance by measuring imager lag and analyzing the expected degradation of the DQE as a function of dose. Finally, comparisons between reconstructed images of the Catphan phantom in terms of qualitative quality and signal-difference-to-noise ratio (SDNR) are made for 6 MV images using both conventional and LKH-5 EPIDs as well as for the kilovoltage (kV) on-board imager (OBI). Results: Analysis of the NPS reveals linearity at all measured doses using the prototype LKH-5 detector. While the first zero of the MTF is much lower for the LKH-5 detector than the conventional EPID (0.6 cycles/mm vs. 1.6 cycles/mm), the normalized NPS (NNPS) multiplied by total quanta (qNNPS) of the LKH-5 detector is roughly a factor of 7-8 times lower, yielding a DQE(0) of approximately 8%. First, second, and third frame lag was measured at approximately 23%, 5%, and 1% respectively, although no noticeable image artifacts were apparent in reconstructed volumes. Analysis of low dose performance reveals that DQE(0) remains at 80% of its maximum value at a dose as low as 7.5x10-6 MU. For a 400 projection technique, this represents a total scan dose of 0.0030 MU, suggesting that if imaging doses are increased to a value typical of kV-CBCT scans (~2.7 cGy), the LKH-5 detector will retain quantum noise limited performance. Finally, comparing Catphan scans, the prototype detector exhibits much lower image noise than the conventional EPID, resulting in improved small object representation. Further, SDNR of H2O and polystyrene cylinders improved from -1.95 and 2.94 to -15 and 18.7, respectively. Conclusions: Imaging performance of the prototype LKH-5 detector was measured and analyzed for both planar and 3D contexts. Improving noise transfer of the detector results in concurrent improvement of DQE(0). For 3D imaging, temporal characteristics were adequate for artifact-free performance and at relevant doses, the detector retained quantum-noise limited performance. Although quantitative MTF measurements suggest poorer resolution, small object representation of the prototype imager is qualitatively improved over the conventional detector due to the measured reduction in noise.
关键词： EPID,NPS,scintillator,MV-CBCT,DQE,MTF,Portal imaging
更新于2025-09-23 15:23:52
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Rapid Multisite Remote Surface Dosimetry for Total Skin Electron Therapy: Scintillator Target Imaging
摘要： Verifying radiation-field uniformity in total skin electron therapy is important to ensuring adequate and effective treatment administration. This clinical study presents a novel, scintillation-based, optical-imaging technique for conducting surface dosimetry in patients undergoing total skin electron therapy. The system exceeded the ease of use of established dosimetry techniques at a similar level of accuracy.
关键词： total skin electron therapy,optical imaging,surface dosimetry,scintillator,remote dosimetry
更新于2025-09-23 15:23:52
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Improving light yield measurements for low-yield scintillators
摘要： Light power spectra are introduced as a new tool for relative light yield (LY) determinations. Light event spectra have commonly been used for this purpose. Theoretical background supporting this change is provided. It is shown that the derivative of a light power spectrum can provide a reliable LY measurement at levels as low as 2% of those for high-yield liquid scintillators. Applications to light evolution in the PPO+LAB system and to water-based liquid scintillators are described.
关键词： light yield,data analysis,water-based scintillator,liquid scintillator
更新于2025-09-23 15:22:29