ESTRO 2025 - Abstract Book

S2934

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

ESTRO 2025

Figure 2 shows a plot of DSC for each CTV. All CTVs other than CTVp_5400 had a majority of contours score above 0.85, indicating good conformity.

Conclusion: These results show dose to primary CTVs was not significantly impacted by decision to replan or not. This study however does not consider OAR (spinal cord) dose. High DSC between CTVs proves promising. Future work will involve improving DIR technique to include previously excluded participants to increase sample size. Clinician contouring time-saving will also be investigated.

Keywords: Deformable, conformity, accumulation

4424

Digital Poster Dosimetric evaluation of two cardiac substructure segmentation approaches: walls versus chambers

Gerard Walls 1,2,3 , Tom Marchant 4 , Alan McWilliam 4 , Marcel van Herk 4 , Corinne Faivre-Finn 1,2 , Kathryn Banfill 1 1 Department of Clinical Oncology, Christie NHS Foundation Trust, Manchester, United Kingdom. 2 Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom. 3 Patrick G Johnston Centre for Cancer Research, Queen’s University Belfast, Belfast, United Kingdom. 4 Radiotherapy Related Research Group, University of Manchester, Manchester, United Kingdom Purpose/Objective: Radiotherapy-related heart disease is a significant toxicity for patients undergoing treatment for intrathoracic cancers. The risk of cardiac events and excess mortality is associated with individual cardiac substructure dose distribution and baseline cardiovascular risk factors. Evidence suggests that established circulating biomarkers of cardiac disease, such as troponin, have a weak correlation with radiation dose, and limited predictive value for toxicity. Cardiac chamber doses are conventionally calculated from segmentations comprising both the myocardial wall and the contained blood. However, cardiac biomarkers are released exclusively from the cardiac tissues. We therefore aimed to evaluate the dosimetric relationship between myocardial wall and whole chambers in a prospective lung cancer radiotherapy cohort.