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Experimental verification of the applicability of the AQURE IOERT accelerator for FLASH radiotherapy

Lenartowicz-Gasik Aleksandra, Misiarz Agnieszka, Adrich Przemysław, Wronka Sławomir, Piotrowski Tomasz, Pawałowski Bartosz, Nowaczyk Piotr, Trzuskowski Jan, Rzadkiewicz Jacek

Polish Journal of Medical Physics and Engineering

2025

Vol. 31, Iss. 1

62--72

Introduction: FLASH radiotherapy is based on delivering an ultra-high dose of ionizing radiation in a very short time, which allows for the enhanced protection of healthy tissues and the effective destruction of tumour tissues. The paper presents experimental verification of the applicability of the intraoperative electron radiotherapy (IOERT) accelerator to obtain electron beams with ultra-high dose rates. The results of electron beam dosimetric measurements were compared with simulations to verify the parameters of the electron beams obtained in FLASH mode. Material and Methods: The IOERT AQURE accelerator is designed and manufactured at the National Centre for Nuclear Research. The device provides electron beams with energies in the energy range of 4-12 MeV. The accelerator was recently upgraded to deliver ultra-high-dose rates (FLASH). The emitted electron beams were verified by percentage dose depth (PDD) and beam profile measurements using Gafchromic EBT-XD films. The measurement results were compared with Monte Carlo simulations performed using the Geant4 application. Results: Conventional and FLASH electron beam parameters, i.e. depths of doses, most probable beam energies at the phantom surface, and average beam energies at the phantom surface were determined experimentally for the upgraded IOERT accelerator for 6 MeV and 9 MeV. The results of dose measurements showed that the accelerator can provide electron beams with homogeneous and symmetrical fields with dose rates up to 300 Gy/s ± 6 Gy/s, for an electron beam at a nominal energy of 6 MeV, and up to 440 Gy/s ± 9 Gy/s at a nominal energy of 9 MeV. A comparison of measured and simulated PDDs and dose profiles for FLASH beams showed good agreement (no worse than 90%) under the gamma index of 3%/3 mm. Conclusions: The results obtained confirm that the upgraded intraoperative accelerator can be used in planned, pre-clinical radiobiology experiments in both conventional and ultra-high dose rate (FLASH-RT) modes.

Commissioning, dosimetric characterisation and machine performance assessment of the AQURE mobile accelerator for intraoperative radiotherapy

Ryczkowski Adam, Pawałowski Bartosz, Kruszyna-Mochalska Marta, Misiarz Agnieszka, Lenartowicz-Gasik Aleksandra, Wosicki Maksymilian, Jodda Agata, Adrich Przemysław, Piotrowski Tomasz

Polish Journal of Medical Physics and Engineering

2024

Vol. 30, Iss. 3

177--181

Introduction: The AQURE is a recently designed mobile linear accelerator for intraoperative electron radiotherapy (IOERT). In the study, we assess, report, and compare the dosimetric characteristics obtained during the commissioning of this machine in our Centre. Material and Methods: The electron energies of the AQURE used in this study are 4, 6, 9 and 12 MeV. The diameters of the cylindrically shaped applicators range from 4 to 10 cm. The measurements were performed (a) by microDiamond detector in a BeamScan water phantom (depth dose distributions, flatness and symmetry of dose profiles, output constancy and linearity) and (b) by Farmer ionisation chamber in a solid water phantom (output related to gantry angle). The results of measurements were compared to analogous results from other IOERT accelerators and were evaluated in the light of scientific recommendations and legal regulations. Results: The values of the measured parameters fit the recommended ranges. The profiles and the depth dose distributions are close to literature data for other IOERT machines. Any differences between them are caused by the detailed technical solutions which influence the final shape of the obtained dose distributions. The values of mean and most probable energies suggest that the electron beams used during IOERT cannot be considered mono-energetic. We believe that the energy spectrum should be researched and described for each IOERT mobile accelerator before clinical usage. Conclusion: The measurements confirm the dosimetric accuracy of the AQURE accelerator under the literature guidelines.