ESTRO 2024 - Abstract Book

S5352

Radiobiology - Tumour biology

ESTRO 2024

Conclusion:

For the same prescribed physical dose of 12 Gy/1# or 18 Gy/3#, the significantly faster treatment time on Truebeam resulted in much higher mean BED 2.47 , effectively delivering a “hotter” treatment compared to GK or CK. This suggests that a reduction in the physical dose to 11 Gy/1# or 17.25 Gy/3# on Truebeam would yield a similar mean BED 2.47 as these historically slower modalities, from which the original VS doses were empirically derived. The addition of even a small margin of 0.5 mm yielded a further elevated BED 2.47 , which may increase the risk of toxicity to adjacent cranial