Temperature Dependence of Novel Inorganic Scintillation Detectors

O’Reilly, David; Qayyum, Kashan; Alharbi, Majed; Foley, Mark

doi:10.1109/sensors47125.2020.9278713

Cited by 4 publications

(5 citation statements)

References 13 publications

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“…Note that the range of SNR observed across the probe array for each source‐probe spacing x is due to small discrepancies in scintillation volume and in‐fiber luminescence coupling efficiency of the probes. We did not observe noticeable signal variation of the MPD with the slight temperature drift in the water phantom during our experiments, thus confirming the very low sensitivity of the Gd 2 O 2 S:Tb to changes in temperature 35,36 …”

Section: Discussionsupporting

confidence: 75%

“…Scintillating powder (Gd 2 O 2 S:Tb) is locally attached to the tapered tip of six of the seven fibers to form the probes P1‐P4, P6, and P7 (see Figure 1b). Gd 2 O 2 S:Tb is chosen as the scintillating material owing to its high scintillation efficiency, stability, linearity and fast temporal response 32–34 and with very low sensitivity to temperature (in the range of 15°–40°) 35,36 . This inorganic scintillator shows an energy dependence 30 that need to be corrected if a direct dose rate measurement, rather than a source tracking, is targeted.…”

Section: Methodsmentioning

confidence: 99%

“…Gd 2 O 2 S:Tb is chosen as the scintillating material owing to its high scintillation efficiency, stability, linearity and fast temporal response [32][33][34] and with very low sensitivity to temperature (in the range of 15 • -40 • ). 35,36 This inorganic scintillator shows an energy dependence 30 that need to be corrected if a direct dose rate measurement, rather than a source tracking, is targeted. The last bare fiber, labelled as P5, is used to evaluate the level of spurious Cerenkov signal generated within fibers upon irradiation.…”

Section: Multiprobe Systemmentioning

confidence: 99%

“…We did not observe noticeable signal variation of the MPD with the slight temperature drift in the water phantom during our experiments, thus confirming the very low sensitivity of the Gd 2 O 2 S:Tb to changes in temperature. 35,36 Beyond the opportunity of inserting a seven-probe detector within a brachytherapy needle, the advantage of the miniaturization of a water nonequivalent fiber dosimeter resides in a smaller volume averaging effect in the strong dose gradients of the radioactive source, as well as a minimum electron fluence perturbation.…”

Section: Detector Specification and Calibrationmentioning

confidence: 99%

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Six‐probe scintillator dosimeter for treatment verification in HDR‐brachytherapy

Gonod,

Suarez,

Avila

et al. 2023

Medical Physics

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BackgroundIn vivo dosimetry (IVD) is gaining interest for treatment delivery verification in HDR‐brachytherapy. Time resolved methods, including source tracking, have the ability both to detect treatment errors in real time and to minimize experimental uncertainties. Multiprobe IVD architectures holds promise for simultaneous dose determinations at the targeted tumor and surrounding healthy tissues while enhancing measurement accuracy. However, most of the multiprobe dosimeters developed so far either suffer from compactness issues or rely on complex data post‐treatment.PurposeWe introduce a novel concept of a compact multiprobe scintillator detector and demonstrate its applicability in HDR‐brachytherapy. Our fabricated seven‐fiber probing system is sufficiently narrow to be inserted in a brachytherapy needle or in a catheter.MethodsOur multiprobe detection system results from the parallel implementation of six miniaturized inorganic Gd2O2S:Tb scintillator detectors at the end of a bundle of seven fibers, one fiber is kept bare to assess the stem effect. The resulting system, which is narrower than 320 microns, is tested with a MicroSelectron 9.14 Ci Ir‐192 HDR afterloader, in a water phantom. The detection signals from all six probes are simultaneously read with a sCMOS camera (at a rate of 0.06 s). The camera is coupled to a chromatic filter to cancel Cerenkov signal induced within the fibers upon exposure. By implementing an aperiodic array of six scintillating cells along the bundle axis, we first determine the range of inter‐probe spacings leading to optimal source tracking accuracy (first tracking method). Then, three different source tracking algorithms involving all the scintillating probes are tested and compared. In each of these four methods, dwell positions are assessed from dose measurements and compared to the treatment plan. Dwell time is also determined and compared to the treatment plan.ResultsThe optimum inter‐probe spacing for an accurate source tracking ranges from 15 to 35 mm. The optimum detection algorithm consists of adding the readout signals from all detector probes. In that case, the error to the planned dwell positions is of 0.01 ± 0.14 mm and 0.02 ± 0.29 mm at spacings between the source and detector axes of 5.5 and 40 mm, respectively. Using this approach, the average deviations to the expected dwell time are of s and s, at spacings between source and probe axes of 5.5 and 20 mm, respectively.ConclusionsOur six‐probe Gd2O2S:Tb dosimeter coupled to a sCMOS camera can perform time‐resolved treatment verification in HDR brachytherapy. This detection system of high spatial and temporal resolutions (0.25 mm and 0.06 s, respectively) provides a precise information on the treatment delivery via a dwell time and position verification of unmatched accuracy.

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Section: Discussionsupporting

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Section: Multiprobe Systemmentioning

confidence: 99%

Section: Detector Specification and Calibrationmentioning

confidence: 99%

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Six‐probe scintillator dosimeter for treatment verification in HDR‐brachytherapy

Gonod,

Suarez,

Avila

et al. 2023

Medical Physics

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“…Scintillation materials, which emit light when excited by high-energy particles, are available in various forms, including organic, − inorganic, − and organic–inorganic composite scintillators. , Organic scintillators offer quick response and flexibility but suffer from lower efficiency and radiation resistance. − In contrast, inorganic scintillators deliver higher efficiency and durability but at a higher cost and with fabrication limitations. − Organic–inorganic composite scintillators, combining organic substances with inorganic scintillation components, offer a promising solution by merging the benefits of both types, such as cost-effectiveness and tunable scintillation properties . These advantages of organic–inorganic composite scintillators make them suitable for practical applications in X-ray panel imaging.…”

Section: Introductionmentioning

confidence: 99%

Enhanced X-ray Imaging with Gd₂O₂S:Pr-Epoxy Composite Films: Synthesis, High-Resolution Performance, and Flexibility

Sun,

Du,

Luo

et al. 2024

ACS Appl. Electron. Mater.

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Organic–inorganic composite scintillation films, recognized for their cost-efficiency and tunable scintillation characteristics, have been the subject of extensive research due to their considerable promise for use in X-ray flat panel imaging applications. This study presents a composite scintillation film utilizing Gd2O2S:Pr phosphors, traditional yet effective in this application. By optimizing the solid-state reaction process and employing acid pickling to eliminate impurities, we achieved Gd2O2S:Pr phosphors with pure phase and precise stoichiometric ratios. Subsequently, these phosphors were combined with epoxy resin to fabricate a composite scintillation film, which demonstrated excellent structural uniformity and flexibility. Furthermore, its imaging performance was evaluated under X-ray irradiation, revealing a resolution of 8 line pairs per millimeter. This outcome underscores the substantial promise of our films for advanced X-ray imaging applications, paving the way for future advancements in this domain.

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Miniaturized scintillator dosimeter for small field radiation therapy

et al. 2021

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The concept of a miniaturized inorganic scintillator detector is demonstrated in the analysis of the small static photon fields used in external radiation therapy. Such a detector is constituted by a 0.25 mm diameter and 0.48 mm long inorganic scintillating cell (1.6 × 10−5 cm3 detection volume) efficiently coupled to a narrow 125 μm diameter silica optical fiber using a tiny photonic interface (an optical antenna). The response of our miniaturized scintillator detector (MSD) under 6 MV bremsstrahlung beam of various sizes (from 1 × 1 cm2 to 4 × 4 cm2) is compared to that of two high resolution reference probes, namely, a micro-diamond detector and a dedicated silicon diode. The spurious Cerenkov signal transmitted through our bare detector is rejected with a basic spectral filtering. The MSD shows a linear response regarding the dose, a repeatability within 0.1% and a radial directional dependence of 0.36% (standard deviations). Beam profiling at 5 cm depth with the MSD and the micro-diamond detector shows a mismatch in the measurement of the full widths at 80% and 50% of the maximum which does not exceed 0.25 mm. The same difference range is found between the micro-diamond detector and a silicon diode. The deviation of the percentage depth dose between the MSD and micro-diamond detector remains below 2.3% within the first fifteen centimeters of the decay region for field sizes of 1 × 1 cm2, 2 × 2 cm2 and 3 × 3 cm2 (0.76% between the silicon diode and the micro-diamond in the same field range). The 2D dose mapping of a 0.6 × 0.6 cm2 photon field evidences the strong 3D character of the radiation-matter interaction in small photon field regime. From a beam-probe convolution theory, we predict that our probe overestimates the beam width by 0.06%, making our detector a right compromise between high resolution, compactness, flexibility and ease of use. The MSD overcomes problem of volume averaging, stem effects, and despite its water non-equivalence it is expected to minimize electron fluence perturbation due to its extreme compactness. Such a detector thus has the potential to become a valuable dose verification tool in small field radiation therapy, and by extension in Brachytherapy, FLASH-radiotherapy and microbeam radiation therapy.

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Temperature Dependence of Novel Inorganic Scintillation Detectors

Cited by 4 publications

References 13 publications

Six‐probe scintillator dosimeter for treatment verification in HDR‐brachytherapy

Six‐probe scintillator dosimeter for treatment verification in HDR‐brachytherapy

Enhanced X-ray Imaging with Gd₂O₂S:Pr-Epoxy Composite Films: Synthesis, High-Resolution Performance, and Flexibility

Miniaturized scintillator dosimeter for small field radiation therapy

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Temperature Dependence of Novel Inorganic Scintillation Detectors

Cited by 4 publications

References 13 publications

Six‐probe scintillator dosimeter for treatment verification in HDR‐brachytherapy

Six‐probe scintillator dosimeter for treatment verification in HDR‐brachytherapy

Enhanced X-ray Imaging with Gd2O2S:Pr-Epoxy Composite Films: Synthesis, High-Resolution Performance, and Flexibility

Miniaturized scintillator dosimeter for small field radiation therapy

Contact Info

Product

Resources

About

Enhanced X-ray Imaging with Gd₂O₂S:Pr-Epoxy Composite Films: Synthesis, High-Resolution Performance, and Flexibility