ESTRO 2025 - Abstract Book

S4086

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

ESTRO 2025

2370

Digital Poster Comparison of respiratory volumes between upright and supine body positions: a study with patients receiving radiotherapy for lung or breast cancer Boisbouvier Sophie 1 , Criscuolo Anthony 2,3 , Underwood Tracy 4,5 , Grégoire Vincent 1 1 Radiotherapy, Centre Léon Bérard, Lyon, France. 2 Radiotherapy and radiation Dosimetry, National Physical Laboratory, Teddington, United Kingdom. 3 School of Mathematics and Physics, University of Surrey, Guildford, United Kingdom. 4 Translational Research department, Leo Cancer Care Ltd, Crawley, United Kingdom. 5 Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom Purpose/Objective: Delivering RT in upright body positions (UP) could be beneficial for breast and lung cancer due to anatomical changes relative to the supine positions (SP) 1 . The present study compared respiratory volumes, the longest possible deep inspiration breath holds (DIBH) and patient comfort in SP and UP. Material/Methods: After ethical approval (R201-004-288), 8 breast cancer patients and 7 lung cancer patients (5 men and 2 women) were included in a spirometry study during their SP RT. During 5 sessions, tests were performed in both positions. To avoid influence of patient fatigue, the starting position was alternated in each of the sessions. For SP, patients were setup on a breast board with arms up. In UP, patients were setup on an upright positioner (Leo Cancer Care) with a specific arm supports. Data collected included Tidal Volume (TV), Expiratory Reserve Volume (ERV), Inspiratory Capacity (IC), and longest DIBH. Vital capacity (VC) was calculated from the ERV and IC. Patients were asked to highlight any uncomfortable body part, before and after the tests, for both positions. They filled out a 10 item questionnaire designed to appraise their experience and their preferred body position. Results: The spirometry tests were performed over an average of 11 days. For the first session, 9 patients started the tests in UP and 6 patients started in SP. ERV was significantly smaller for SP than for UP (p<0.05). TV and IC were significantly larger for SP than for UP (p<0,05). There was no statistically significant difference in VC between the two positions (p>0.9). The longest DIBH were between 21.5 - 92.2s and 24.7 - 122.2s for the UP and the SP respectively (p>0.09). For a maximum of 5 and 10% of the tests, patients reported discomfort in at least one body part, in UP and SP, respectively. Responses from the questionnaire are presented in fig 1 and 2.