ESTRO 2025 - Abstract Book

S3633

Physics - Quality assurance and auditing

ESTRO 2025

2153

Proffered Paper Machine- and Patient-specific Quality Assurance for STereotactic Arrhythmia Radioablation (STAR): Consensus Statement from the STOPSTORM.eu Consortium Melanie Grehn 1 , Adam Bekman 2 , Aleksandra Grządziel 3 , Łukasz Dolla 3 , Tomasz Latusek 4 , Marcin Miszczyk 5,6 , Stefanie Ehrbar 7 , Martin F. Fast 8 , Francesca R. Giglioli 9 , Lone Hoffmann 10 , Lukáš Knybel 11 , Veronica Richetto 9 , Etienne Pruvot 12 , Joost J.C. Verhoeff 13 , Slawomir Blamek 4 , Oliver Blanck 1 1 Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany. 2 Medical Physics Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice, Poland. 3 Radiotherapy Planning Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice, Poland. 4 Radiotherapy Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice, Poland. 5 Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria. 6 Collegium Medicum - Faculty of Medicine, WSB University, Dąbrowa Górnicza, Poland. 7 Department of Radiation Oncology, University Hospital of Zurich and University of Zurich, Zurich, Switzerland. 8 Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands. 9 Medical Physics Unit, A.O.U. Città della Salute e della Scienza di Torino, Torino, Italy. 10 Department of Oncology, Aarhus University Hospital, Aarhus, Denmark. 11 Department of Oncology, University Hospital and Faculty of Medicine, Ostrava, Czech Republic. 12 Heart and Vessel Department, Lausanne University Hospital, Lausanne, Switzerland. 13 Department of Radiation Oncology, Amsterdam UMC, Amsterdam, Netherlands Purpose/Objective: Stereotactic Arrhythmia Radioablation (STAR) of ventricular tachycardia is technically challenging due to complex target volume delineation, cardiorespiratory motion, and single-high-dose application in the heart. The STOPSTORM.eu consortium (EU-Horizon-2020-Grant 945119) aims to investigate, optimise, and harmonise STAR in Europe [1]. We now aimed to define best practice recommendations for machine and patient-specific stereotactic body radiotherapy (SBRT) and STAR-specific quality assurance (QA) in a two-round Delphi process. Material/Methods: An expert panel from eight countries prepared the first draft of the best practice statements. Twenty STOPSTORM centres voted and commented on the statements in the first round. The comments were considered for the second round and statements were refined or added where necessary. The final vote for the statements that were relevant for the centres’ used machine was based on a 5-point Likert-scale (5: strongly agree to 1: strongly disagree). Positive consensus was defined as ≥80% (strong agreement; SA) or ≥66% (moderate agreement; MA) of the participating centres voting with 4 or 5 on the Likert-scale. Voting concordance of <66% was interpreted as no agreement (NA). Results: The Delphi process resulted in 22 general SBRT- and 11 STAR-specific-QA statements where SA was reached for 21, MA for 5, and NA for the remaining 7 of them (Figure-1/2). The SBRT statements were categorized: machine audits (1 SA, 1 NA), commissioning and general QA (8 SA, 2 MA, 2 NA), system-geometry and image-guidance (2 SA, 1 MA, 1 NA), computed tomography (1 SA, 1 NA), and end-to-end and patient-specific QA (2 SA). For STAR, consensus was reached that additional audits and commissioning procedures are not required beyond (inter)national recommendations for SBRT (2 SA). Furthermore, consensus was reached that surface-guidance-techniques are considered only supportive to primary image-guidance, and that image quality tests should assess the impact of metallic artifacts (e.g., ICD or LVAT) on planning and image guidance (2 SA). MA was reached that the same performance tests for the planning-CT are also required for the ECG-gated-cardiac-CT (1 MA). Consensus was also reached for statements on patient-specific STAR-QA (3 SA and 1 MA). NA was reached that STAR-specific end-to-end tests must be performed for combined cardiorespiratory motion (2 NA).