Real-time dosimetry of ultrahigh dose-rate x-ray beams using scintillation detectors

Shaharuddin, Shahirah; Hart, Alexander; Cecchi, Daniel D.; Bazalova‐Carter, Magdalena; Foley, Mark

doi:10.1109/sensors47087.2021.9639825

Cited by 4 publications

(2 citation statements)

References 19 publications

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“…Scintillator detectors, which produce optical photons in response to ionizing radiation, may be an alternative which avoid the previously mentioned problems. Combining fast response times (and the ability for real-time readout), with sub-mm spatial resolution, and dose rate independence for a variety of radiation types and sources [14]- [20], radioluminescent detectors are excellent dosimeters for use across the spectrum of dose rates em-ployed in preclinical studies and radiotherapy [21]- [23]. There are a wide range of scintillating materials including organic (polystyrene and polyvinyltoluene-based plastics), and inorganic scintillators.…”

Section: Introductionmentioning

confidence: 99%

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

Hart,

Giguére,

Bateman

et al. 2024

Preprint

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Very high energy electron (VHEE) beams with energies greater than 100 MeV may be promising candidates for FLASH radiotherapy due to their favourable dose distributions and accessibility of ultrahigh dose-rates (UHDR). Combining VHEE with the normal tissue-sparing FLASH effect of UHDR radiotherapy could improve patient outcomes. The standard dosimeters used for conventional radiotherapy, including ionization chambers and film, have limited application to UHDR radiotherapy due to deficits in dose rate independence and temporal resolution. Plastic scintillator detectors (PSDs) are a potential alternative. PSDs connected to a Medscint Hyperscint RP-100 were used to measure the response to 200 MeV electrons produced by the CERN Linear Electron Accelerator for Research (CLEAR). The dose-response linearity and radiation hardness of PSDs under UHDR VHEE conditions was investigated, using dose rates up to 1.21 × 10 Gy/s. Two scintillators were investigated: a polystyrene-based BCF-12 and a proprietary polyvinyltoluene (PVT)-based material. The BCF-12 probe exhibited linear light output with dose per train from 4.9 to 125.2 Gy, and dose rates up to 1.16 × 10 Gy/s within a single pulse. The output of the PVT-based probe was linear from 3.9 to 59.5 Gy per train, and dose rates up to 9.92 × 10 Gy/s. While output linearity was retained (R > 0.998) after delivering 26.2 and 13.8 kGy to the BCF-12 and PVT-based probe, respectively, the light output was reduced by < 1.5%/kGy. The performance of PSDs in this work suggest they may be useful real-time dosimeters for applications in UHDR VHEE radiotherapy.

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Section: Introductionmentioning

confidence: 99%

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

Hart,

Giguére,

Bateman

et al. 2024

Preprint

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“…Luminescence detectors offer most of those desired characteristics 8,9 . Fiber‐coupled scintillators are suitable candidates that have been used before in UHDR electron, 10,11 proton 12 and x‐ray beams 13 . However, they have so far only been used for measurement of the total delivered dose 10,11,13 or the spot durations 12 rather than the time‐resolved dose rate.…”

Section: Introductionmentioning

confidence: 99%

Time‐resolved dose rate measurements in pencil beam scanning proton FLASH therapy with a fiber‐coupled scintillator detector system

et al. 2022

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Background:The spatial and temporal dose rate distribution of pencil beam scanning (PBS) proton therapy is important in ultra-high dose rate (UHDR) or FLASH irradiations. Validation of the temporal structure of the dose rate is crucial for quality assurance and may be performed using detectors with high temporal resolution and large dynamic range. Purpose: To provide time-resolved in vivo dose rate measurements using a scintillator-based detector during proton PBS pre-clinical mouse experiments with dose rates ranging from conventional to UHDR. Methods: All irradiations were performed at the entrance plateau of a 250 MeV PBS proton beam. A detector system with four fiber-coupled ZnSe:O inorganic scintillators and 20 μs temporal resolution was used for dose rate measurements. The system was first characterized in terms of precision and stem signal. The detector precision was determined through repeated irradiations with the same field. The stem signal contribution was quantified by irradiating two of the detector probes alongside a bare fiber (fiber without a coupled scintillator). Next, the detector system was calibrated against an ionization chamber (IC) with all four detector probes and the IC placed in a water bath at 2 cm depth. A scan pattern covering 9.6 × 9.6 cm was used. Multiple irradiations with different requested nozzle currents provided instantaneous dose rates at the detector positions in the range of 7-1270 Gy/s. The correspondence of the detector signal (in Volts) to the instantaneous dose rate (in Gy/s) was found.The instantaneous dose rate was calculated from the beam current and the spot-to-detector distance assuming a Gaussian beam profile at distances up to 8 mm from the spot. Afterwards, the calibrated system was used in vivo, in mouse experiments, where mouse legs were irradiated with a constant dose and varying field dose rates of 0.7-87.5 Gy/s. The instantaneous dose rate was measured for each delivered spot and the delivered dose was determined as the integrated instantaneous dose rate. The spot dose profile and PBS dose rate map were calculated. The dose contamination to neighbouring mice were measured together with the upper limit of the dose to the mouse body. Results: The detectors showed high precision with ≤0.4% fluctuations in the measured dose. The stem signal exceeded 10% for spots <5 mm from the This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Plastic Scintillator Dosimetry of Ultrahigh Dose-Rate 200 MeV Electrons at CLEAR

Hart,

Giguère,

Bateman

et al. 2024

IEEE Sensors J.

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Real-time dosimetry of ultrahigh dose-rate x-ray beams using scintillation detectors

Cited by 4 publications

References 19 publications

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

Time‐resolved dose rate measurements in pencil beam scanning proton FLASH therapy with a fiber‐coupled scintillator detector system

Plastic Scintillator Dosimetry of Ultrahigh Dose-Rate 200 MeV Electrons at CLEAR

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