ESTRO 2024 - Abstract Book

S4880

Physics - Quality assurance and auditing

ESTRO 2024

For the guidelines, we reached strong agreement on several aspects of STAR including beam technique planning, dose calculation, prescription methods and trade-offs between target and critical structures. In particular, for well known single fraction dose limits of extra-cardiac OARs, 100% of the participants agreed that Planning Target Volume (PTV) dose tradeoff must be in favor of Organs at Risk (OARs) sparing to minimize risks of severe and fatal toxicities. However, we found larger differences on specific cardiac substructures (coronary arteries and valves) dose limitations takes made by the participating institutions, especially on their dose constraints or the lack thereof in current literature, as shown in Figure 1. No agreement (63%) on necessary dose inhomogeneity in the target to reach a therapeutic effect was reached. Participants were not in agreement also regarding the use of plans with high modulation factor and the maximum dose to the ICD electrodes (with 53% and 58% of agreement, respectively). Furthermore, regarding ICD electronics management, the consortium reached moderate agreement regarding the use of specific beam energies to avoid malfunctions as well as beam avoidance of the main ICD electronics (79% agreement).

Figure 1. % of agreement regarding the dosimetric constraints for cardiac substructures (coronary arteries on the top and valves on the bottom) for the participating institutions. TV = Target Volume, ALARA = As Low As Reasonably Achievable.

Conclusion:

Current treatment planning approaches for STAR are still heterogeneous in Europe. After our previously reported treatment planning benchmark and discussion within the STOPSTORM.eu consortium, we observed agreements in