Report on the 2024 ESTRO Physics Workshop report

18-19 October 2024 I Krakov, Poland

Thirty-one people from Europe and the USA participated in this ESTRO Physics Workshop, at which were discussed ideas on ways to improve open-source software development and resource-sharing in radiotherapy. The participants focused on ways to develop open-source software for research and clinical applications, as well as the increased use of scripting for radiotherapy treatment-planning systems. Attendees included open-source software developers and users and participants of the software from both research and clinical settings.

The workshop had three invited speakers: Csaba Pintér of Ebatinca, who spoke about the experiences and lessons learned during the development of and work with large-scale open-source software (specifically, Slicer-RT); Julien Uzan of Raysearch, who gave the perspective of the treatment-planning system software vendor; and Josh Kirby of the Northern Centre for Cancer Care (UK), who gave a clinical perspective on resource-sharing and scripting. In addition, some participants offered short presentations on different aspects such as how to navigate the EU Medical Device Regulation (MDR), how to obtain manufacturer non-disclosure agreements, and experience of gaining approvals and implementing clinical open-source software developments.

Before the workshop, a survey on open-source and resource-sharing was distributed by ESTRO; this received over 100 responses. The survey respondents highlighted many existing examples of open-source software and resource-sharing platforms. The findings suggested many ways to share resources, including through the commissioning of reports and templates/protocols in addition to scripts and software. The barriers to resource-sharing that were highlighted included lack of time, inability to support users, intellectual property issues and legislation/governance issues.

The workshop proceeded to open discussions that covered open-source developments, scripts, and sharing for artificial intelligence applications such as deep-learning auto-contouring models. The topics for discussion included how to establish a registry and make it visible, how to maintain and develop resources to ensure sharing could be sustained over time, how to licence and how to overcome barriers such as MDRs.

Finally, the participants divided into four groups to discuss in more detail and to start to develop action plans in the following areas.

• Development of a registry for open-source resources in radiotherapy
• Development of a recommendation for open-source development and publishing
• Collection of examples of successful clinical resource sharing to present as "best practice" recommendations for the navigation of regulations
• Promotion of resource sharing and keeping the topic active amongst ESTRO members and beyond, possibly steered by a dedicated group within ESTRO

Overall, the workshop was successful in establishing work towards the improvement of resource-sharing amongst the radiotherapy community, to the benefit of ESTRO members and ultimately our patients.

Ana Maria Barragan Montero (Belgium), Josh Mason ((UK), Niklas Wahl (Germany)