ESTRO 2021 Abstract Book

S539

ESTRO 2021

After continuously training, with a SGRT core team and vendor support all staff members are now able to use the system optimally. We try to use our SGRT systems for as many setups as possible to optimize the patient comfort. Patients with a difficult or complicated set up will be evaluated and all staff members are able to make the decision if SGRT would be suitable. Continuously (re-)training and a thorough preparation are the key to a successful implementation of SGRT systems. SP-0675 The challenge of surface-guided radiotherapy - When, and when not, to use it? V. Batista 1 1 Heidelberg University Hospital, Department for Radiation Oncology and Radiation Therapy, Heidelberg, Germany Abstract Text The distinguished characteristics of surface-guided radiotherapy, as non-ionizing imaging modality, and its ability to monitor the three-dimensional patient surface in real-time, turns this technique attractive to all radiotherapy body sites [Freislederer2020]. Actually, its integration into the radiotherapy chain was been showing several benefits, as reduction of imaging dose and setup time, improving safety, and concurring with application of motion management methods [Hosaik2020]. However, some difficulties might urge in transiting to SGRT-workflows, compromising its benefits [Batista2020]. One of them, is the understanding that SGRT has different applications (patient setup, intra-fractional monitoring, surrogate for beam-gating, etc.), and therefore can’t be applied in the same way to all tumour sites. The use of SGRT for initial setup might benefit all the body sites [Carl2018, Haraldsson2020], but it must be followed by internal-imaging for all the sites where a weak surface-tumour correlation is observed. Its use as tool to monitor intra-fractional motion should be also considered to all the patients, as might help into the detection of unexpected/involuntary motion (coughing, extremities motion, tremors, etc.), nevertheless it should be clear to the RTTs how to interpret the data given by the system and which actions to perform at the time of its occurrence. Beam-gating supported by SGRT is promising, as 6DOF real-time information without additional dose is given, however the distinction between superficial- and deep-seated tumours must be considered, when setting accuracies, tolerances and methodology [Heinzerling2020]. SGRT showed also to be feasible and might improve accuracy in special techniques/applications (as particle therapy, SBRT, paediatrics, among others), when complemented with other imaging modalities and in a quality assured specific-workflow [Hosaik2020]. Moreover, SGRT started to be pointed out as a tool to improve patient safety, through patient identification, setup correctness, and forcing a workflow standardisation, and therefore, applicable to every patient. However, its implementation into clinical settings, requires to break some habits, acquisition of multidisciplinary background and a structured implementation process. The fact that SGRT gives the user additional data, in a fraction of seconds, and reacts patient-specific, compromises a broad application to all patients in many clinics. In resume, this session envisages to discuss the dualities/controversies that emerge from the adoption of SGRT; review the main benefits and challenges in using SGRT, from tumour-sites to application-type; and discuss how to weigh benefits and mitigate pitfalls. [Batista2020] doi.org [Carl2018] doi.org

[Freislederer2020] doi.org [Haraldsson2020] doi.org [Heinzerling2020] doi.org [Hosaik2020] ISBN 9781138593497

SP-0676 Surface-guided radiotherapy for breast cancer in deep inspiration breath hold K.T. Beer 1 1 Radio-Onkologie Zentrum Biel-Seeland-Berner Jura, -, Biel-Bienne, Switzerland

Abstract Text Rationale: Implementation of Deep Inspiration Breathhold (DIBH) treatment with Surface Guided Radiotherapy (SGRT) to reduce heart toxicity in order to minimise excess cardiac toxicity Methods: Commissioning of SGRT system Align RT Important considerations: • Shared decision by technicians, phycisists, and clinicians • Compatibility with treatment machines • Versatility • Ease of handling • Reduction of kV-MV imaging Establish accuracy before universal application Figure 1: Enhanced accuracy with SGRT