TY  - JOUR
AU  - Oancea, Cristina
AU  - Sykorova, Katerina
AU  - Jakubek, Jan
AU  - Pivec, Jiri
AU  - Riemer, Felix
AU  - Worm, Steven
AU  - Bourgouin, Alexandra
TI  - Dosimetric and temporal beam characterization of individual pulses in FLASH radiotherapy using Timepix3 pixelated detector placed out-of-field
JO  - Physica medica
VL  - 129
SN  - 1120-1797
CY  - Amsterdam
PB  - Elsevier
M1  - PUBDB-2025-01216
SP  - 104872
PY  - 2025
N1  - Waiting for fulltext
AB  - Background: FLASH radiotherapy necessitates the development of advanced Quality Assurance methods and detectors for accurate monitoring of the radiation field. This study introduces enhanced time-resolution detection systems and methods used to measure the delivered number of pulses, investigate temporal structure of individual pulses and dose-per-pulse (DPP) based on secondary radiation particles produced in the experimental room. Methods: A 20 MeV electron beam generated from a linear accelerator (LINAC) was delivered to a water phantom. Ultra-high dose-per-pulse electron beams were used with a dose-per-pulse ranging from  1 Gy to over 7 Gy. The pulse lengths ranged from 1.18 µs to 2.88 µs at a pulse rate frequency of 5 Hz. A semiconductor pixel detector Timepix3 was used to track single secondary particles. Measurements were performed in the air, while the detector was positioned out-of-field at a lateral distance of 200 cm parallel with the LINAC exit window. The dose deposited was measured along with the pulse length and the nanostructure of the pulse. Results:The time of arrival (ToA) of single particles was measured with a resolution of 1.56 ns, while the deposited energy was measured with a resolution of several keV based on the Time over Threshold (ToT) value. The pulse count measured by the Timepix3 detector corresponded with the delivered values, which were measured using an in-flange integrating current transformer (ICT). A linear response (R<sup>2</sup> = 0.999) was established between the delivered beam current and the measured dose at the detector position (orders of nGy). The difference between the average measured and delivered pulse length was  0.003(30) μs. Conclusion: This simple non-invasive method exhibits no limitations on the delivered DPP within the range used during this investigation.
LB  - PUB:(DE-HGF)16
C6  - 39667142
UR  - <Go to ISI:>//WOS:001385622400001
DO  - DOI:10.1016/j.ejmp.2024.104872
UR  - https://bib-pubdb1.desy.de/record/625891
ER  -