ESTRO 2022 - Abstract Book

S248

Abstract book

ESTRO 2022

With DIBH, the lung volume increased by on average 54% compared to FB, while heart and PTV volumes were reduced by 6% and 7% (Fig 1). While DIBH showed a slightly lower median PTV V 95% , all dosimetric parameters for the lungs, heart and spinal canal were clearly advantageous. For the esophagus, no significant differences were found (Table 1). Fig 2 points at large inter-patient variations in dosimetric differences between FB and DIBH, especially for the esophagus which could move either towards or away from the PTV due to DIBH. For 30/33 patients, DIBH resulted in a lower lung D mean than FB (>2 Gy for 15 patients), and the heart D mean was lower for 23/33 patients (>2 Gy for 5 patients). Table 1: Dose-volume parameters for FB and DIBH.

Conclusion For most LA-NSCLC patients, DIBH reduced lung and heart dose compared to FB. However, dosimetric advantages varied considerably between patients, with individual patients showing large benefits, others with no or minor benefits, and for a few patients DIBH was inferior to FB. Automated planning could facilitate individualized selection between FB and DIBH with virtually zero workload and no planner bias.

OC-0288 Fully automated VMAT technique for radiation therapy of high-risk breast cancer

L. Redapi 1 , L. Marrazzo 1 , R. Pellegrini 2 , P. Voet 3 , I. Meattini 4 , C. Arilli 5 , M. Casati 1 , A. Compagnucci 1 , C. Talamonti 5,6 , M. Zani 7 , L. Livi 8 , S. Pallotta 1,9 1 Azienda Ospedaliera Universitaria Careggi, Medical Physic Unit, Florence, Italy; 2 Elekta AB, Global Clinical Science & Research Clinical Liaison, Stockholm, Sweden; 3 Elekta AB, Global Clinical Science & Research Clinical Liaison , Stockholm, Sweden; 4 University of Florence, Radiation Oncology Unit, Department of Experimental Biomedical and Clinical Medicine,