ESTRO 2025 - Abstract Book

S4043

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

ESTRO 2025

Material/Methods: A comprehensive search was conducted across multiple databases, including MEDLINE Ovid (PubMed), EMBASE, and the Web of Science Core Collection, covering the period from 2019 to 2024. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to identify studies relevant to respiratory motion management in lung SBRT. Data extracted included target volume delineation, target volume sizes, and dosimetric lung dose metrics reported. Results: The review included 14 studies involving 273 patients with early-stage primary lung cancer or solitary lung metastases, where both active (breath-hold, phase-gating, and tracking) and non-active (Internal Target Volume based) respiratory motion management strategies were used. Active respiratory motion management approaches were associated with significantly reduced target volume sizes (non-active 36.35 cm 3 vs. breath-hold 26.26 cm 3 vs. phase-gating 30.18 cm 3 vs. tracking 12.48 cm 3 ) and lung doses (non-active 8.3% cm 3 vs. breath-hold 3.4% vs. phase gating 8.3% vs. tracking 3.8%) compared to non-active approaches. Tracking demonstrated superiority in target volume reduction (Tracking 34.2% vs. deep inspiration breath-hold 23.9% vs. Gating 32.9%), and lung protection (Tracking 39.2% vs. deep inspiration breath-hold 39.5% vs. Gating 20.2%). Patients with tumours exhibiting greater motion (>10 mm) benefit more from active approaches. Conclusion: Accounting for target volume and lung doses, tracking was superior to other active approaches in lung SBRT treatment. Deep inspiration breath-hold shows comparable lung protection but breath-hold is challenging for patients with lung diseases. Patient selection is crucial when determining the most appropriate respiratory motion management approach. Poster Discussion Improving Patient Positioning Reproducibility with a Vacuum Mattress in Hyperthermia Treatment for Locally Recurrent Breast Cancer Anton Rink, Martine Franckena, Patrick Granton, Carolina Carrapiço-Seabra, Abdelali Ameziane, Inge Lieben, Sergio Curto Radiotherapy, Erasmus MC, Rotterdam, Netherlands Purpose/Objective: In the Netherlands, reirradiation (re-RT) combined with hyperthermia (HT) is the standard treatment for patients with locally recurrent breast cancer. The added value of HT has been validated by randomized trials and meta analysis [1]. Furthermore, HT dose–effect studies have demonstrated positive correlations between temperatures and clinical outcomes, highlighting the importance of accurate thermal delivery [2]. Currently, patient positioning is maintained using soft cushions (Figure 1). However, this method often leads to reproducibility challenges and temperature variations between treatment sessions. The objective of this study is to assess whether the use of a vacuum mattress results in more more stable and reproducible positioning. This will be evaluated by measuring inter-fractional temperature differences, where smaller differences indicate improved reproducibility. Keywords: respiratory motion management, lung neoplasms 266