EXPANDING PROTON FLASH CAPABILITIES TO kGy /s WITHIN ms FOR CLINICAL APPLICATIONS AT HZB

Background and aimsThe HZB Cyclotron facility is able to deliver proton FLASH irradiation, providing beamtime to Charité – Universitätsmedizin Berlin for in vivo and in vitro experiments. For these studies, a spread-out Bragg peak with a maximum dose rate of 100 Gy/s has been applied within 200 ms at a maximum energy of 68 MeV. Since then, various system upgrades have been implemented with the aim to increase the achieved dose rate and shorten the irradiation time. The involved components and their performance are presented below.

MethodsBetween the cyclotron and its injector, an electrostatic deflector has been installed, which is controlled by an FPGA board and acts as an adjustable beam shutter, providing irradiation times down to 1 ms. Within such short durations, the delivered beam intensity can be safely increased without damaging the vacuum window at the beam exit and without reaching the radiation safety limits. The increased dose rates from a mm-focused beam are then measured by an Advanced Markus Chamber (PTW-Freiburg, Germany) and monitored by an in-house developed transparent ionization chamber, connected to a UNIDOS webline electrometer (PTW-Freiburg, Germany).

ResultsBoth ionization chambers have shown a linear response with respect to the beam current for dose rates up to 4 kGy/s. An irradiation time of 1 ms has been achieved with a statistical fluctuation of 4%, while the clinical requirement of <2% dose uncertainty can be achieved with irradiation times longer than 2.5 ms.

ConclusionsThe updated FLASH capabilities of the HZB Cyclotron enable a reliable delivery, measurement and monitoring of proton dose rates in the order of several kGy/s within few ms. In combination with the available 3D range modulator, the parameter space for systematic clinical experiments is broadened remarkably.

Content

Author and article information

Journal

Title: ScienceOpen Posters

Publisher: ScienceOpen

Publication date (Electronic preprint): 11 November 2022

Affiliations

[1 ] Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Hahn-Meitner-Platz 1, D 14109 Berlin, Germany

[2 ] Charité – Universitätsmedizin Berlin, Berlin Protonen am Helmholtz-Zentrum Berlin, Germany

[3 ] Berliner Hochschule fuer Technik, Berlin, Germany

Author notes

[* ]Email: georgios.kourkafas@ 123456helmholtz-berlin.de .

Author information

Georgios Kourkafas https://orcid.org/0000-0002-0881-504X

Article

DOI: 10.14293/S2199-1006.1.SOR-.PPRDNQW.v1

SO-VID: 7c1f893b-b161-43d9-be8c-d24d4ff8c5b6

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This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

History

Date received : 11 November 2022

Data availability: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

ScienceOpen disciplines: Medical physics,Physics

Keywords: proton,double scattering,spread-out Bragg peak,cyclotron,HZB,eye tumor,modulator,organoid,FLASH

References

Kourkafas Georgios, Bundesmann Juergen, Fanselow Timo, Denker Andrea, Ehrhardt Vincent Henrique, Gollrad Johannes, Budach Volker, Weber Andreas, Kociok Norbert, Joussen Antonia M., Heufelder Jens. FLASH proton irradiation setup with a modulator wheel for a single mouse eye. Medical Physics. Vol. 48(4):1839–1845. 2021. Wiley. [Cross Ref]

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[1] Kourkafas Georgios, Bundesmann Juergen, Fanselow Timo, Denker Andrea, Ehrhardt Vincent Henrique, Gollrad Johannes, Budach Volker, Weber Andreas, Kociok Norbert, Joussen Antonia M., Heufelder Jens. FLASH proton irradiation setup with a modulator wheel for a single mouse eye. Medical Physics. Vol. 48(4):1839–1845. 2021. Wiley. [Cross Ref]