ESTRO 2025 - Abstract Book

S2826

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2025

Results: The use of favorable non-coplanar beam orientations allowed to improve target coverage, dose conformity and/or OAR sparing for all patients. In particular, significant reductions in the maximum cumulative EQD2 to critical OARs such as bronchial tree (up to -9.0 Gy 2 ), esophagus (up to -5.8 Gy 2 ), trachea (up to -5.3 Gy 2 ) and thoracic wall (up to - 12.6 Gy 2 ) were achieved for few patients using optimized non-coplanar versus coplanar arcs. At the same time, the mean lung EQD2 was reduced on average by 0.2±0.1 Gy 2 and lung V20Gy 2 was reduced on average by 0.7±0.7%. The greatest improvement of OAR doses was observed in a case depicted in Figure 2. For this case, the maximum cumulative EQD2 to bronchial tree, esophagus and great vessel could be reduced by 9.0 Gy 2 (132.3 vs 141.3 Gy 2 , - 6.4%), 5.0 Gy 2 (90.9 vs 95.9 Gy 2 , -5.2%) and 5.6 Gy 2 (115.0 vs 120.6 Gy 2 , -4.6%), respectively, for a similar target coverage.