A 3D RANGE MODULATOR FOR ULTRA-SHORT PROTON FLASH IRRADIATION

In the pursuit of optimal parameters for FLASH irradiation, all components involved in the beam delivery should be compatible with requirements spread in an extreme and wide unexplored regime. Aiming for minimal total irradiation times with modulated proton beams, which deliver a flat depth-dose distribution along tumors, a static range modulator has been developed to accommodate ultra-short beam durations regardless of their time structure. The design goals were set to match the functionality of the rotating wheel used for in-vivo and in-vitro FLASH investigations at HZB.

Methods

Having the form of a ridge filter extended to an additional dimension, a hexagonal-pyramid pattern was configured to an incoming beam of 23 MeV energy with > 1 mm radius, in order to create a 6 mm uniform field with a flat dose range of 5 mm at the target. The manufacturing was done with a 3D printer using VeroWhite, a material similar to PMMA. The lateral and distal dose distribution of both modulators were measured using a Markus Chamber (PTW-Freiburg, Germany) in a water phantom and a radioluminescent screen mounted in front of CCD camera, respectively.

Results

The developed modulator created very flat dose distributions as designed, with negligible differences to the reference rotating wheel. The positioning tolerances were evaluated as relatively relaxed, with offsets of 2 cm and an angle of 5 degrees not compromising the desired performance.

Conclusions

The developed static modulator allows systematic proton FLASH studies on small organs using a broad range of timing schemes, disentangled from temporal and spatial incoherencies.

Content

Author and article information

Journal

Title: ScienceOpen Posters

Publisher: ScienceOpen

Publication date (Electronic preprint): 16 November 2021

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

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-.PPHZA3O.v1

SO-VID: 469647b6-a176-4176-b78a-7c7ed7048c4e

License:

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 : 16 November 2021

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: FLASH,ultra-high dose rate radiotherapy,proton radiotherapy,static modulator,3D ridge filter,spread-out Bragg peak

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]

Comments

Comment on this article

[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]