ESTRO 2021 Abstract Book

S152

ESTRO 2021

slightly increased. Significant median reduction of mean dose, V 5 Gy , V 20 Gy , V 40 Gy Perc 75, with significant positive repercussions on the mean dose, V 5 Gy , and V 20 Gy well. The only statistically significant drawbacks were the median increase of V 40 Gy in Perc 50 (+0 . 07 %) and in the body (+0 . 28 %), which were considered clinically acceptable trade-offs. No significant dose changes were observed in the PTV, heart and spinal cord. All the results for lung and body VOIs are summarised in figure 2b. No correlation was found between the PTV volume (11 − 1312 mL ) and the modification of any dose parameter by functional planning. and max dose were observed in in Perc 50 and Perc 25 as

Conclusion Perfusion SPECT based functional lung sparing optimisation is feasible and leads to a statistically significant dose reduction of functional lung volumes. Using the presented methodology, prospective functional lung sparing can be safely introduced into clinical practice.

Poster highlights: Poster Highlights 8: Breast

PH-0219 Ten-year results of hypofractionated whole breast RT and intraoperative boost in premenopausal women S. Dicuonzo 1 , C. Cormio 1 , C.I. Fodor 1 , A. Morra 1 , D.P. Rojas 1 , M.A. Zerella 1 , F. Cattani 2 , V.E. Galimberti 3 , P. Veronesi 3,4 , M. Zaffaroni 1 , R. Orecchia 5 , M.C. Leonardi 1 , B.A. Jereczek-Fossa 1,4