Report on the ESTRO Physics Workshop
23-24 October 2025 | Toulouse, France

Chairs:

• Tom Depuydt, medical physicist, University Hospital Gasthuisberg, Leuven, Belgium
• Gabriel Piava Fonseca, medical physicist, Maastricht University, Maastricht, The Netherlands

 

Across Europe, 3D printing has rapidly moved from an experimental add-on to a widely available tool in radiotherapy departments, but its true potential in radiation oncology has yet to be fully realised. This ESTRO Physics Workshop in Toulouse, led by chairs Professor Ir Tom Depuydt (Leuven, Belgium) and Dr Gabriel Paiva Fonseca (Maastricht, The Netherlands), brought together medical physicists, engineers, and industry partners to consider the current limitations and share their expertise and views on how 3D printing should be brought through evidence-based and collaborative frameworks to the radiotherapy community. Before heading to Toulouse, participants connected in an online pre-meeting to introduce their backgrounds and expertise, setting the stage for productive collaboration.

The in-person workshop opened with an initial analysis of a global survey on the use of 3D printing in radiotherapy. The results provided a broad overview of countries that used it, highlighting the clinical motivations behind its use, and expectations for future developments. The group also identified clear limitations in the dataset, such as the fact that in some countries, all survey respondents reported using 3D printing even though this did not reflect national practice, revealing bias. Therefore, the participants agreed to collaborate on expanding the survey outreach to those who did not then use 3D printing. This follow-up effort might lead to a publication to highlight the current situation.

Figure 1: (Left) Workshop opening session discussion on the global 3D printing in radiotherapy survey led by Dr Fonseca; (centre) discussion on the involvement of industry, led by Prof. Depuydt; and (right) wrap-up presentation to all workshop groups showing the survey’s global coverage.

The next sessions featured short participant presentations, each followed by open discussion. The focus was first on in-house 3D-printing; centres showed how they integrated 3D printing into their work, specifically research, including manufacturing phantoms. While in-house printing is particularly valuable for research and rapid prototyping, many centres face similar technical and procedural challenges. To address these shared limitations, the group agreed to explore a collaborative platform for exchanging practical information, such as filament characteristics, to boost the efficiency of implementation across institutions.

Next, the workshop discussed standardisation in clinical 3D-printing workflows. Seven centres presented their in-house 3D-printed skin applicators for brachytherapy as a case example. 3D-printed equipment such as applicators and personalised boluses are becoming more widely used, but participants noted differences in imaging approaches, choices of design and materials, and verification procedures. Yet the overall structure of the workflows proved remarkably similar. Several centres mentioned that they were eager to implement 3D printing for patient-specific devices, but that the lack of clear, shared guidance still made each new project feel like an isolated effort. In addition, the impact of the Medical Device Regulation (MDR) emerged repeatedly as a significant barrier that was holding back broad adoption by creating regulatory uncertainty for many centres. The combination of this clear overlap in practice and the collective need for more alignment led to a proposal to develop a joint consensus paper. This paper would map out the main workflow options, explain their advantages and limitations, and provide practical guidance, particularly for centres currently without in-house expertise.

In the next session, the added value of 3D printing and its supporting evidence were examined. After an invited talk by Prof. James Robar, participants agreed that 3D printing had moved beyond being a technological novelty, but that robust evidence remained limited. Most available studies rely on single-centre, in-house workflows, underscoring the need for broad validation. The discussion covered different types of added value, from clinical outcomes to improved patient comfort, as well as the importance of accessible 3D printing to deliver basic care in resource-limited countries. Participants stressed that stronger evidence was essential to justify the effort and resources required to install and use 3D-printing facilities and to support adoption by management and industry. Proposed next steps included increasing the volume and quality of evidence, consolidating existing data, promoting multi-centre studies, and developing initiatives for implementation in resource-limited settings.

The workshop’s last session was dedicated to industry perspectives on 3D printing in radiotherapy. Participants noted that scaling 3D printing toward broad clinical adoption, particularly beyond large academic centres, would require strong involvement from both radiotherapy vendors and the 3D-printing industry. Speakers highlighted the need to create added value for all stakeholders, including clinics, industry partners, and ultimately patients. Different implementation models were explored, ranging from full in-house production through point-of-care solutions provided by industry to complete outsourcing. This raised the question of which approach best supported long-term sustainability and MDR compliance. A recurring theme was the importance of integrating 3D-printing capabilities directly into treatment planning systems, to enable seamless design and use of patient-specific devices. Professionalisation and standardisation were identified as key drivers for routine clinical adoption.

This initiative marks an important step toward unlocking the full value of 3D printing in radiation oncology and supporting a more standardised, collaborative, and innovative European practice. The workshop underscored both the interest in 3D printing and the persistent gaps in knowledge and evidence. While in-house rapid prototyping continues to drive creativity and fast innovation, the community emphasised the need to strengthen the quality and quantity of supporting data. Sharing expertise, training, and best practices remains essential, as does advancing standardisation and working closely with industry to achieve broad, sustainable adoption. Continued efforts to mature the technology—and to integrate 3D design and manufacturing more seamlessly into clinical radiotherapy systems and workflows—will be crucial if 3D printing is to move from being a promising “maker” tool toward being a widely accessible, high-value clinical asset.

Figure 2: Participants and organisers.

 

Writers:

Didier Lustermans

MAASTRO, Maastricht

The Netherlands

 

Bertrand Dewit

KU Leuven, Leuven

Belgium