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Baikalov, A. ; Tho, D.* ; Liu, K.* ; Bartzsch, S. ; Beddar, S.* ; Schüler, E.*

Characterization of a time-resolved, real-time scintillation dosimetry system for ultra-high dose rate radiation therapy applications.

Int. J. Radiat. Oncol. Biol. Phys., DOI: 10.1016/j.ijrobp.2024.11.092 (2024)
DOI PMC
: Postprint online available 12/2025
BACKGROUND: Scintillation dosimetry has promising qualities for ultra-high dose rate (UHDR) radiotherapy (RT), but no system has shown compatibility with mean dose rates (DR‾) above 100 Gy/s and doses per pulse (Dp) exceeding 1.5 Gy typical of UHDR (FLASH)-RT. The aim of this study was to characterize a novel scintillation dosimetry system with the potential of accommodating UHDRs. METHODS AND MATERIALS: We undertook a thorough dosimetric characterization of the system on an UHDR electron beamline. The system's response as a function of dose, DR‾, Dp, and the pulse dose rate (DRp) was investigated, as was the system's dose sensitivity (signal per unit dose) as a function of dose history. The capabilities of the system for time-resolved dosimetric readout were also evaluated. RESULTS: Within a tolerance of ±3%, the system exhibited dose linearity and was independent of DR‾ and Dp within the tested ranges of 1.8-1341 Gy/s and 0.005-7.68 Gy, respectively. A 6% reduction in the signal per unit dose was observed as DRp was increased from 8.9e4 to 1.8e6 Gy/s. The dose delivered per integration window of the continuously sampling photodetector had to remain between 0.028 and 11.56 Gy to preserve a stable signal response per unit dose. The system accurately measured Dp of individual pulses delivered at up to 120 Hz. The day-to-day variation of the signal per unit dose in a reference setup varied by up to ±13% but remained consistent (<±2%) within each treatment day and showed no signal loss as a function of dose history. CONCLUSIONS: With daily calibrations and DRp-specific correction factors, the system reliably provides real-time, millisecond-resolved dosimetric measurements of pulsed conventional and UHDR beams from typical electron linacs, marking an important advancement in UHDR dosimetry and offering diverse applications to FLASH-RT and related fields.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Dosimetry ; Flash Radiotherapy ; Scintillator ; Ultra-high Dose Rates
ISSN (print) / ISBN 0360-3016
e-ISSN 0360-3016
Publisher Elsevier
Non-patent literature Publications
Reviewing status Peer reviewed