ESTRO 2025 - Abstract Book

S3914

Radiobiology - Normal tissue radiobiology

ESTRO 2025

Results: The dose-response curves are depicted in Figure 2. (1) The RBE for severe acute damage was 1.06±0.02, and 1.16±0.08 for severe late damage using single fraction doses in the center of the SOBP. (2) The RBE was 1.25±0.06 for severe late damage using four fractions in the center of the SOBP. (3) The RBE was enhanced at the distal edge with an RBE of 1.15±0.02 for severe acute damage and 1.26±0.09 for severe late damage using single fraction doses.

Conclusion: The results clearly demonstrate a heterogenic RBE; (1) a 10% higher RBE for severe late damage than severe acute damage; (2) a 9% higher RBE using four fractions than one fraction; (3) and a 9-10% higher RBE at the distal edge than in the center of the SOBP.

Keywords: RBE, Protons, acute and late damage