Wyniki wyszukiwania - BazTech

1

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

EN

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.

2

Opracowanie cyfrowego układu sterowania prądem cewek korekcyjnych dla akceleratora przemysłowego

Markopolskyi Vasyl, Lenartowicz-Gasik Aleksandra, Wysokiński Jerzy, Baczewski Artur, Pyszczak Natalia

Elektronika : konstrukcje, technologie, zastosowania

|

2025

|

Vol. 66, Nr 3

7--10

PL

Publikacja przedstawia cyfrowe rozwiązanie systemu sterowania i kontroli pól magnetycznych odpowiedzialnych za położenie i kształt generowanej w akceleratorze liniowym elektronów wiązki promieniowania. Opisany w publikacji system został opracowany, zweryfikowany również przez przeprowadzenie testów jego pracy i wprowadzony na produkcji w akceleratorach LILLYPUT stosowanych do badań nieniszczących. Obejmuje on kontrolę, regulację i stabilizację prądu w wszystkich cewkach skupiających i korekcyjnych akceleratora z pominięciem układu zasilania solenoidu generującego pole magnetyczne skupiające elektrony na całej długości struktury akceleracyjnej. Zbudowany system zapewnia stabilność pracy na poziomie 1% zadanej wartości prądu cewek w zakresie powyżej 100 mA, poprawiając dotychczasowo stosowane analogowe rozwiązanie pięciokrotnie.

EN

The publication presents a digital control and monitoring system for magnetic fields responsible for the positioning and shaping of the electron beam generated in a linear accelerator. The described system has been developed, validated through operational testing, and implemented in production for LILLYPUT accelerators used in non-destructive testing. It encompasses the control, regulation, and stabilization of current in all focusing and correction coils of the accelerator, excluding the power supply system of the solenoid that generates the magnetic field focusing electrons along the entire length of the acceleration structure. The developed system ensures operational stability at a level of 1% of the set coil current value for currents above 100 mA, improving the previously used analog solution by a factor of five.

3

Verification of real-time dosimetry of ultra-high dose rate beams at AQURE FLASH RT on the sample surface

Lenartowicz-Gasik Aleksandra, Misiarz Agnieszka, Markopolski Vasyl, Walo Marta, Gryczka Urszula, Bułka Sylwester, Pawałowski Bartosz, Kruszyna-Mochalska Marta, Rzadkiewicz Jacek

Polish Journal of Medical Physics and Engineering

|

2024

|

Vol. 30, Iss. 4

300--304

EN

Introduction: FLASH radiotherapy involves delivering a dose of ultra-high-dose-rate ionising radiation (>40 Gy/s) in less than 200 ms, resulting in sparing healthy tissue and effectively destroying cancerous tissue. This article presents a preliminary verification of the feasibility of using real-time internal dosimetry at the sample surface to measure doses generated by the AQURE FLASH RT accelerator dedicated to FLASH radiotherapy studies. Material and Methods: The AQURE FLASH RT emits a 6 and 9 MeV electron beam with a dose rate higher than 40 Gy/s. The real-time dosimetry system to measure doses on the sample surface was implemented into the accelerator and consists of inductive sensors in which the moving electron charge induces a voltage in the secondary toroidal winding. The internal dosimetric system was preliminarily calibrated for single pulse irradiations using passive dosimetry methods, i.e. film and alanine dosimetry. Results: The study showed that there was no effect of the tested dosimetry system on the beam (PDD and beam profile). The linearity of the system’s response to successive pulses was tested and found to be <2% only for irradiation with two or more pulses. Therefore, a single pulse calibration of the system was performed to verify the applicability of the system for single pulse irradiation. The measurement results showed that the differences between the results obtained by the different methods were less than 2% for triode grid voltages below 30 V. Conclusion: The results confirmed the possibility of using the real-time dosimetry system to measure doses on the sample surface delivered by ultra-high dose rate beams at the AQURE FLASH RT accelerator. The system has been tested and validated over the full range of dose rates emitted by the accelerator to measure a dose in a single pulse. The results of the dosimetric measurements confirmed that the system did not affect the beam parameters.

4

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

EN

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.