ESTRO 2024 - Abstract Book

S4360

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

Conclusion:

Anatomical disagreement between CBCT and generated sCTs compared to rCT images can cause dose differences greater than 2.0%. Therefore, for each individual patient with lung cancer, anatomical changes in an oART setting must be carefully evaluated. This finding indicates the need for patient- and fraction-specific quality assessment, which is unavailable in the current version of the commercially available oART system used in this study. A future solution for the reported density alteration issues could potentially be direct dose calculation on a CBCT with better image quality and a true Hounsfield Unit representation. The study concludes that using the current version of the oART workflow is not suitable for patients with lung cancer, where occurring anatomical changes causes density alterations, resulting in inaccurate density mapping of the sCT images and consequently incorrect dose calculations.

Keywords: online adaptive RT, Lung cancer, thoracic changes