ESTRO 2024 - Abstract Book

S5271 ESTRO 2024 These findings contribute to our understanding of the mechanistic basis that renders COPD lung tissue more susceptible to radiation. Importantly, our study suggests that these airway stem cells can serve as a valuable experimental human model for comorbidities in lung cancer patients that may be used to identify prognostic and predictive biomarkers and develop therapeutic strategies to minimise normal tissue damage during radiotherapy. Radiobiology - Normal tissue radiobiology

Keywords: COPD, stem cells, RT sensitivity

References:

Giuranno, L., E.M. Roig, C. Wansleeben, A. van den Berg, A.J. Groot, L. Dubois, and M. Vooijs, NOTCH inhibition promotes bronchial stem cell renewal and epithelial barrier integrity after irradiation. Stem Cells Transl Med, 2020. 9(7): p. 799-812.

Giuranno, L., J. Ient, D. De Ruysscher, and M.A. Vooijs, Radiation-Induced Lung Injury (RILI). Front Oncol, 2019. 9: p. 877.

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Proffered Paper

Spread-out Bragg Peak proton FLASH: Comparing early and late toxicity of FLASH in a mouse model

Line Kristensen 1,2 , Per Poulsen 1 , Eleni Kanouta 1 , Sky Rohrer 1 , Christina Ankjærgaard 3 , Claus E Andersen 3 , Jacob G Johansen 1 , Yuri Simeonov 4 , Uli Weber 5 , Cai Grau 1 , Brita Singers Sørensen 1,2 1 Aarhus University Hospital, Danish Centre for Particle Therapy, Aarhus, Denmark. 2 Aarhus University Hospital, Department of Experimental Clinical Oncology, Aarhus, Denmark. 3 DTU, Health Tech, Roskilde, Denmark. 4 Institut für Medizinische Physik und Strahlenschutz, Technische Hochschule Mittelhessen, Giessen, Germany. 5 GSI, Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany

Purpose/Objective:

Preclinical studies have indicated a favourable effect of ultra-high dose rate (FLASH) radiation, in which adverse effects of radiation damage are reduced without compromising tumour control. Most studies of proton FLASH investigate these effects within the entrance of a proton beam. However, the real advantage of proton therapy lies in the Spread-out Bragg Peak (SOBP), which allows for giving high dose to a target with limited dose to healthy tissue at the entrance of the beam. Therefore, a clinically relevant investigation of the FLASH effect would be of healthy tissues within a SOBP. Our study aimed to determine the tissue-sparing effect of FLASH radiation on toxicity within a SOBP. To quantify this effect, we sought to produce comparable dose-response curves for acute and late toxicities.

Material/Methods:

Radiation-induced damage was assessed for both acute and late toxicity in the same mice following irradiation with FLASH (Field dose rate of 60 Gy/s) or conventional (CONV, 0.4 Gy/s) dose rates. The presented preliminary data includes 78 female CDF1 mice. The right hindleg of unanaesthetised mice were irradiated with single-fraction