ESTRO 2025 - Abstract Book

S4097

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2025

enable the technique to be expanded more effectively and provide greater insights into its broader applications. This study aims to evaluate these parameters in patients treated by stereotactic ablative radiotherapy (SABR) for liver and pancreatic cancer. Material/Methods: Ventilation parameters from 21 patients who underwent SABR with MANIV were analysed. Each patient underwent a unique coaching session with a physiotherapist to learn the technique and set the ventilation parameters (pressure, exsufflation time and rise time). The goal was to achieve a series of consecutive 30sec breath-holds (MANIV-BH) via an oronasal mask in Airway Pressure Release Ventilation (APRV) mode after four minutes of preoxygenation (FiO 2 60%). Subsequently, patients underwent their treatment with identical ventilation parameters during the five SABR sessions. The parameters defined during the coaching session were analysed across all sessions and patients, including the median duration of each treatment session (considering patient installation, IGRT x2, and SABR delivery - Fig.1). We conducted a paired-samples t-test to compare the duration of the first and last sessions.

Results: The data of 21 patients (70.0 years; IQR: 12) were included in this analysis. All patients except one directly achieved the succession of 30-sec MANIV-BH after the coaching session. Median APRV settings were as follows: pressure: 17.0 cmH ₂ O (IQR: 2.0), exsufflation time: 5.0 seconds (IQR: 0.7), and rise time: 250.0 milliseconds (IQR: 100.0) (Fig.2). The median session times were 41.0 (IQR: 14), 37.0 (IQR: 17), 34.0 (IQR: 16), 32.0 (IQR: 10), and 30.0 (IQR: 11) minutes for sessions 1 to 5, respectively. The duration of the first session was significantly different from the last session (p < 0.05) for a same administered dose.