ESTRO 2021 Abstract Book

S1255

ESTRO 2021

Conclusion Cardioablation appears to be particularly suitable for older patients with multiple comorbidities, for whom standard procedures can be contraindicated. Target motion and doses to the organs at risk are the most important factors to be considered when irradiating AF foci. More studies are warranted to define the best method to safely and efficiently perform a stereotactic RT ablation for AF. PO-1532 The elephant in the room: teaching OAR delineation in a FALCON workshop in the autosegmentation era E. Rivin del Campo 1 , J. Cacicedo Fernandez de Bobadilla 2 , C. Valentini 3 , N. Andratschke 4 , W. Mohamed 5 , A. Abrunhosa-Branquinho 6 , G. Chiloiro 7 , S. Duke 8 , S. Hol 9 , I. Nobre Góis 10 , G. Meijer 11 , M. Palmu 12 , E. Forde 13 1 Tenon University Hospital, Sorbonne University, Radiation Oncology, Paris, France; 2 Hospital Universitario Cruces/ Biocruces Health Research Institute/University of the Basque Country, Radiation Oncology, Barakaldo, Vizcaya (Basque Country), Spain; 3 Klinik und Poliklinik für Strahlentherapie und Radioonkologie, Medizinische Fakultät und Universitätsklinikum Carl Gustav Carus Dresden, Technische Universität Dresden, Radiation Oncology, Dresden, Germany; 4 UniversitätsSpital Zürich, University of Zurich, Radiation Oncology, Zurich, Switzerland; 5 Swansea University hospital UK, Lecturer of Oncology PortSaid University, Radiation Oncology, Swansea, United Kingdom; 6 Centro Hospitalar Lisboa Norte, Radiation Oncology, Lisbon, Portugal; 7 Policlinico Universitario Agostino Gemelli, Radiation Oncology, Rome, Italy; 8 Addenbrooke, Cambridge University Hospitals, Radiation Oncology, Cambridge, United Kingdom; 9 Institute Verbeeten, Radiation Oncology, Tilburg, The Netherlands; 10 Coimbra Hospital and University Center (CHUC), University of Coimbra, Faculty of Medicine (FMUC), Radiation Oncology, Coimbra, Portugal; 11 UMC Utrecht, Medical Physics, Utrecht, The Netherlands; 12 European Society for Radiotherapy and Oncology (ESTRO), Project Manager, Brussels, Belgium; 13 Applied Radiation Therapy Trinity, Discipline of Radiation Therapy, Trinity St. James’s Cancer Institute, Trinity College Dublin, Radiation Oncology, Dublin, Ireland Purpose or Objective Autosegmentation is becoming ubiquitous in the clinical radiation oncology workflow. Autosegmentation has the potential to decrease OAR contouring variability, and to increase efficiency in the treatment planning workflow. However, there are no standards for evaluating autosegmentation platforms to assess their efficacy at meeting these goals. The purpose of this pilot segment was to integrate the evaluation of autosegmented contours within the context of a FALCON (Fellowship in Anatomic Delineation and Contouring) workshop: During the FALCON OAR Thorax online workshop, held in December 2020, the course directors planned a pilot segment using MVision’s autocontouring. A lung SBRT case with an associated dose plan was chosen from FALCON’s EduCase ™ library for contouring of OAR Thorax. During the second live online session, a 10 minute lecture on autosegmentation was planned. Afterwards, questions on interpretations of autocontouring structures for polling exercises were asked. To end the autocontouring segment, MVision’s autosegmented OAR Thorax contours were reviewed on FALCON EduCase ™ . A satisfaction questionnaire was given to participants after the workshop, to evaluate it on a Likert scale, from 1 (strongly disagree) to 5 (strongly agree). Results The OAR Thorax workshop included 21 participants from 16 countries. Eighty-three percent were female. Their professions were RTTs (41.7%), Radiation Oncology specialists (33.3%), Radiation Oncology Trainees (16.7%) and Radiation Physicist Specialists (8.33%). Four polling questions were asked, two examples are illustrated in figures 1 and 2. On average, 87% of the participants adequately responded to the polling questions. However, 3 of the 4 polling questions allowed several options to be chosen, thus this average calculated by adding all the correct answers for each question is most probably overestimated. At the end of the workshop, participants were shown the expert contours along with the autosegmented contours (by scrolling down the whole image set), and the differences were commented by the faculty and the tutor. To finish, the dose distribution was presented along with the expert and the autosegmented contours, and commented as well. “Organs at risk thorax”. Materials and Methods