ESTRO 2024 - Abstract Book

S3370

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Conclusion:

The aim of this study is to use a semi-analytic solution method to obtain an expression for the ion recombination correction factor in high DPP beams. An extrapolation procedure based on the derived expression that can be used in a clinical setting is proposed. Using this extrapolation procedure, an accurate determination of the recombination correction factor can be obtained for DPP values below 1 Gy for chambers of 1 mm plate separation and below 3 Gy for chambers of 0.5 mm plate separation, provided the fit of the expressions to measured data are performed above voltages between 200-300 V.

Keywords: FLASH, UHDPP, recombination

References:

1. K. Petersson, M. Jaccard, J.-F. Germond, T. Buchillier, F. Bochud, J. Bourhis, M.-C. Vozenin, and C. Bailat, “High dose per-pulse electron beam dosimetry — A model to correct for the ion recombination in the Advanced Markus ionization378 chamber,” Medical Physics, vol. 44, no. 3, pp. 1157–1167, 2017.

2. R. Kranzer, D. Poppinga, J. Weidner, A. Schuller, T. Hackel, H. K. Looe, and B. Poppe, “Ion collection efficiency of ionization chambers in ultra-high dose-per-pulse electron beams,” Medical Physics, vol. 48, no. 2, pp. 819–830, 2021.

2942

Mini-Oral

Impact of the effective point of measurement for plane-parallel ionization chambers in proton beams

Kilian Baumann 1,2,3 , Ana Lourenco 4,5 , Jörg Wulff 6 , Gloria Vilches-Freixas 7 , Hugo Palmans 8,4