ESTRO 2023 - Abstract Book

S1630

Digital Posters

ESTRO 2023

Conclusion The results illustrate that with increasing complexity of the prediction task (longer prediction horizon, noisy data), deep learning (here: LSTM) outperforms the current state-of-the-art LR for respiratory signal prediction to overcome system latencies in SBRT of thoracic tumors.

PO-1887 Gating strategy selection for patients with apical lung lesions in MRgRT SBRT

M. Galetto 1 , M. Nardini 2 , A. Capotosti 2 , L. Boldrini 3 , G. Chiloiro 3 , A. Romano 3 , C. Votta 3 , L. Indovina 2 , L. Placidi 2

1 Università Cattolica del Sacro Cuore, Facoltà di Medicina e Chirurgia, Roma, Italy; 2 Fondazione Policlinico Universitario A. Gemelli IRCCS, UOSD Fisica Medica e Radioprotezione, Roma, Italy; 3 Fondazione Policlinico Universitario A. Gemelli IRCCS, UOC Radioterapia Oncologica, Roma, Italy Purpose or Objective greater patients’ compliance during free breathing (FB) respiratory motion management strategy has been observed, especially due to less treatment time and physical exhaustion (arms up) respect to deep inspiration breath hold (DIBH) strategy. The aim of this study is to quantify the GTV motion of apical lung lesions during a SBRT in a Magnetic Resonance (MR)-LINAC system, supporting the patient specific treatment gating pre-selection during the MR simulation procedure, by measuring the GTV centroid position on MR cine. Materials and Methods 12 patients with apical lung tumour treated with MRgRT SBRT at the ViewRay MRIDIAN system, have been retrospectively enrolled in this study. 6 of the 12 selected patients were treated in FB and the remaining 6 in DIBH gating technique. During the simulation and all the treatment fractions, sagittal cine 0.35T MR allows real-time GTV motion tracking. A home-made MATLAB script has been employed to perform image segmentation on MR cine for measuring the centroid position of the GTV contour. The GTV motion is evaluated by measuring the standard deviation of the GTV centroid position on all cine frames for FB patients, while for DIBH patients GTV motion was acquired during the deep inspiration phase (DIP) in