ESTRO 2024 - Abstract Book

S4242

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

ESTRO 2024

The SGRT system maintained adequate surface coverage and an accurate DIBH-signal at depths averaging 33 cm and 42 cm beyond the treatment iso-center during constant couch speed. Due to the steeper angle of the patient scanned inside the bore and loss of surface images from the two side cameras, effects of occlusion in the clavicular and neck regions were observed for all volunteers. The surface coverage was also influenced by the longitudinal and vertical couch positions within the gantry, the gantry geometry, and patient morphology (Figure 1). Accurate detection of the simulated respiratory motion using the HexaMotion platform was obtained for all cases by the Catalyst + HD TM system during constant couch speed. Significant difference in the dose to the heart and left anterior descending artery (LAD) was found between the DIBH and FB plans as the DIBH plans offered a median (range) average dose reduction up to 27% (13-33%) and 40% (26-49%) (p <0.001) to the heart and LAD respectively. As for the near-maximum dose (D2%) to the heart and LAD, the median (range) dose reduction was 50.0% (47-58%) and 47.0% (42-56%) (p <0.001), respectively. No significant difference between DIBH and FB was observed in the average dose to the PTV and ipsilateral lung, nor in the conformity and homogeneity indices.