ESTRO 2024 - Abstract Book

S79 ESTRO 2024 Furthermore, the presentation will cover additional QA tasks that arise in online adaptive radiotherapy, especially with regard to the basis for adaptive treatment planning and dose calculation, i.e. contours and density information. Lastly, the talk will put patient specific QA in a broader perspective of quality management and process-based QA for online adaptive treatments. Invited Speaker

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Physicist involvement in Stereotactic Arrhythmia Radioablation (STAR): Where does it matter the most and what not to miss?

Oliver Blanck

University Medical Center Schleswig-Holstein, Department of Radiation Oncology, Kiel, Germany

Abstract:

Stereotactic body radiotherapy (SBRT) is a promising therapy for refractory ventricular tachycardia (VT), called stereotactic arrythmia radioablation (STAR). STAR presents unique challenges and close interdisciplinary collaboration is paramount for patient selection and safe and effective treatment [1]. In Europe, more than 200 patients have been treated [2] and initial results show promising safety profiles and VT burden reduction of more than 85 % [3]. Furthermore, details of biological mechanisms of STAR were recently revealed showing electrical conduction reprogramming as main driving factor for treatment success [4]. The treatment workflow is comparable to thoracic SBRT, however with additional incorporation of electrophysiology data and scar imaging for target delineation [3,5]. Since data registration, target definition and target transfer to planning systems is highly variable and not yet standardized [6], dedicated quality assurance means are required for optimal treatment [7]. Furthermore, respiratory- and cardiac-induced target motion needs to be carefully considered [5,8] while organs-at-risk contouring [9] and target dose modulation with close critical structure sparing [10] is addressed during treatment planning. Quality assurance is again routine practice, however, no specific phantoms for STAR exists, limiting the measurement comprehensiveness. Lastly, STAR delivery for the often-frail patients adds another complex problem to this novel treatment and accuracy often must be weighed against deliverability [11]. Due to the unique challenges on all aspects of the treatment chain, the early involvement of medical physicists is paramount when introducing STAR into clinical practice. Smooth cardiology data integration into radiation treatment planning and comprehensive quality assurance have yet the be developed and medical physicists will drive those efforts to overcome current limitations. The important role of medical physicists in clinical trials is also increasingly being recognized [12] and indeed the optimization and harmonization of STAR is being addressed in multi-centric studies [13] and the EU-Horizon-2020 STOPSTORM consortium project [3], significantly supported by medical physicists.

[1] Krug D, Blanck O, Andratschke N, et al. Recommendations regarding cardiac stereotactic body radiotherapy for treatment refractory ventricular tachycardia. Heart Rhythm. 2021;18(12):2137-45.

[2] Grehn M, Mandija S, Miszczyk M, et al. STereotactic Arrhythmia Radioablation (STAR): The Standardised Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant Tachycardia by a Multidisciplinary Consortium (STOPSTORM.eu) and Review of Current Patterns of STAR Practice in Europe. Europace. 2023;25(4):1284-1295.