ESTRO 2025 - Abstract Book

S3954

Radiobiology - Normal tissue radiobiology

ESTRO 2025

Results:

ROOH production clearly indicates sparing effects under UHDR. For PBS deliveries of 15 Gy to a 100x100 mm 2 field at 8 mm depth, the ROOH yield for 50% of the field at 500nA FLASH beam currents is equivalent to a 12.94 Gy delivery at 1nA CONV delivery. At a lower dose of 5 Gy, FLASH reduction in ROOH is minor and equivalent to a 4.76 Gy CONV delivery. The yield of ROOH depends strongly on the dose and beam current but has minimal dependency on the field size and spot spacing. Introducing inter-beam intervals of two minutes reduces the FLASH reduction in ROOH, consistent with murine data.

Conclusion: