ESTRO 2023 - Abstract Book

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ESTRO 2023

only target density showed a p-value of 0.07 with acute toxicity as dependent variable. We further looked into this result performing a Mann-Whitney test that showed, for patients with toxicity, a lower mean HU value (Fig 2) though not significant (p-value=0.08).

Conclusion The significant dose difference observed when changing algorithm, does not show a statistically significant impact in terms of response or toxicity. Our data could support the upgrade to a type-c algorithm without modifying dose prescription. The results on PTV density could indicate, if confirmed with a larger dataset, that PTV density may be a critical factor, whose effect is enhanced when moving to type-c algorithms. For very low densities, however, strategies should be adopted in order to avoid excessive fluence and thus dose increase with respect to the known clinical practice.

PO-1806 Effects of Reconstruction Methods on Dose Distribution for Lung SBRT Plans

Y. Yedekci 1 , P. Hurmuz 2 , G. Ozyigit 2

1 Hacettepe Univertsiy, Radiation Oncology, Ankara, Turkey; 2 Hacettepe University, Radiation Oncology, Ankara, Turkey