European Particle Therapy Network (EPTN)

The European Particle Therapy Network (EPTN) became a task force of ESTRO in 2017. It was established in 2015 in response to the anticipated increase in the number of particle therapy centres in Europe. In addition, the need to cooperate among centres and integrate particles (i.e. protons and carbons) in the framework of clinical research networks was identified as being of paramount importance. ESTRO, at the time of initiation of the network, was asked to collaborate with EPTN and agreed to facilitate the group.

Particle therapy (PT) is only one part of radiation oncology, and needs to be well aligned with other radiation techniques as well as with general developments in cancer research and patient care. PT offers both new opportunities for providing excellence in cancer care, and for high-quality research within the framework of European  networks.

Organisation

The EPTN is led by three co-chairs and is composed of 8 working packages (WP) with experts of different topics to further elaborate the particle European discussions.
The EPTN meets once a year through the EPTN annual meeting.

The EPTN co-chairs are:

• Cai Grau (Aarhus, DK) 
• Damien Weber (Villigen, CH) 
• Dietmar Georg (Vienna, AT)

The EPTN has its own internal standard operating procedure (SOP), covering its policies, aims, and organisation of the network.
Use this link to consult the EPTN SOP.

11^th European Particle Therapy Network (EPTN) Annual Meeting and Workshop

21^st and 22^nd of October 2025, in Prague, Czech Republic.

We are happy to announce that registrations are open for participating in the EPTN Annual Meeting and Workshop in Prague this October.

In addition to the Annual Meeting, an EPTN Workshop will take place on 21st October 2025 in Prague:

Hypofractionation in proton therapy: From radiobiology to the clinic

The workshop objectives are to identify the most critical preclinical data required to support clinical adoption of hypofractionation in proton therapy, explore the clinical, technical, and organisational aspects of clinical implementation of hypofractionation, and define a joint strategy to orchestrate efforts across Europe to foster clinical trials and implementation of hypofractionation.

Discussions will focus on several key areas, including the specific preclinical evidence needed before clinical application, the current status of hypofractionation in daily clinical and technical workflows, and the initiatives and collaborations that can facilitate broader adoption. The workshop will also address the development of scientific proposals necessary to advance this evolving field.

The format of the workshop will include expert presentations, breakout groups, and collaborative roadmap development.

Venue:
MAMA Shelter Prague
Veletržní 1502/20, 170 00 Praha 7-Holešovice, Czechia

Workshop:
📅 Date: 21 October 2025
🕐 Start Time: 13:00 (local time)

Annual Meeting:
📅 Date: 22 October 2025
🕘 Time: 08:30–15:00 (local time)

Agendas will be available shortly.

Please note that the Annual Meeting and Workshop are subject to capacity. Registrations will be closed once capacity is reached.

Please register your participation in the Annual Meeting and the workshop below:
Please be aware that registrations for participating in the Annual Meeting and the workshop are done separately.

• EPTN Annual Meeting 2025:
  https://forms.office.com/e/jVMed6kgBx
• Workshop on Hypofractionation in proton therapy: From radiobiology to the clinic: https://forms.office.com/e/H0LQTWDWfF
   

If you have any questions, please do not hesitate to reach out to us on eptn@estro.org

EPTN Organisers:
Cai Grau (Aarhus, DK), Damien Weber (Villigen, CH), Dietmar Georg (Vienna, AT)

EPTN Work Packages

Each WP is structured with one or more coordinators and is thematically established to cover key challenges and developments related to the EPTN and its work. Some of the core responsibilities and aims of the WPs consist chiefly of engaging in trials, guidelines, white papers, and surveys, as well as establishing and hosting workshops and courses.
Below, each work package is listed with its own dedicated section, outlining its general organisational structure, as well as any particular developments and news from the work package.

Work Package 1: Clinical Evidence

Coordinators:
Hans Langendijk, The Netherlands
Karin Haustermans, Belgium

Work Package 2: Dosimetry, Instrumentation and Quality Assurance

Coordinators:
Oliver Jäkel, Germany
Sairos Safai, Switzerland
Stefano Lorentini, Italy
 

Mission

This work package is dedicated to dosimetry, instrumentation and quality assurance in radiotherapy with protons and light ions. It addresses the need for methods and harmonization in dose measurement across centers in Europe.
 

Objectives

• Disseminate and discuss reference dosimetry protocols suitable for particle therapy (e.g. IAEA TRS-398)
• Facilitate inter-comparison exercises and dosimetry audits
• Interface with primary standards laboratories (e.g. NPL)
• Facilitate multi-center QA harmonization (e.g. survey)
• Share QA procedures, tools, and best practices via surveys, workshops, and online resources.
• Publish guidelines and recommendations in dosimetry (e.g. beam data collection)

 

News

• Abstract at PTCOG 63: oral presentation
  Towards a consensus on measurement-less patient specific QA in proton therapy
  M. Vidal, L. Stolarczyk, L. Grevillot, G. Magro, G. Vilches-Freixas, X. Liang, C. Clark, I. Rinaldi, F. Emert, C. Vallhagen Dahlgren, S. Lorentini, O. Jäkel, A. Lomax, C. Richter and S. Safai
  ​
• Publications
  • Peer-reviewed
    - Gomà C, Henkner K, Jäkel O, Lorentini S, Magro G, Mirandola A, Placidi L, Togno M, Vidal M, Vilches-Freixas G, Wulff J, Safai S. ESTRO-EPTN radiation dosimetry guidelines for the acquisition of proton pencil beam modelling data. Phys Imaging Radiat Oncol. 2024 Aug 5;31:100621. doi: 10.1016/j.phro.2024.100621. PMID: 39220113; PMCID: PMC11364130.

 

Recent events

• 6^th Thematic Workshop (online & on-site) – Out-of-field dosimetry
  Workshop on Out-of-field Dosimetry in Proton Therapy: Translation to Clinical Practice with a Focus on Pregnant Patients (EPTN WP2/WP4-EURADOS joint workshop)
  Part 1: 21 February 2025 - Online
  Part 2: 10–11 March 2025, Maastricht (NL)

 

Ongoing activities

• Implementation of IAEA TRS-398 (2024 Edition)
  • Following the publication of the updated IAEA Code of Practice TRS-398, WP2 is leading efforts to interpret and apply the new recommendations in clinical settings.
  • A draft EPTN-WP2 Commentary summarizing clarifications, consensus points, and identified issues has been produced and will be published to this platform.
     
• Intercomparison of Beam Monitor Calibration
  • A collaborative project aims to compare Gy/MU calibration curves across European centers.
  • The project will continue with standardized testing across multiple centers and the creation of a shared calibration database.
     
• Development of PSQA Consensus (with WP5)
  • Building on the 2023 ESTRO Physics Workshop, WP2 and WP5 are co-developing a consensus on light ion Patient-Specific Quality Assurance.
  • Focus areas include:
    • Independent dose calculations
    • Log-file based QA
    • Risk analysis (FMEA)
    • External audits/surveys
  • Dedicated subgroups and follow-up meetings are ongoing, with industry interest in software integration for testing. ESTRO-EPTN Guidelines proposal have been accepted by the ESTRO guidelines committee and are being written.
     
• Translating Out-of-Field Dosimetry to clinical practice for pregnant patients
  • Following the 6^th WP2 Thematic Workshop held in March 2025 in Maastricht the organizers are defining follow-up activities based on the workshop’s outcomes.
  • Key areas of focus include:
    • Refining measurement protocols and dosimetric models
    • Drafting recommendations for clinical practice
    • Identifying research needs and standardization opportunities
  • Continued collaboration with EPTN WP4 and EURADOS is planned to expand the impact and reach of these efforts.
     
• Validation of LET calculations
  • WP2 supports a new endeavor launched in 2022 by DCPT in collaboration with EURADOS WG9 for the evaluation of LET estimation techniques with experimental campaigns.
  • These efforts aim to assess the feasibility of LET reporting for treatment plan validation in clinical proton therapy.
  • Publication: Iván Domingo Muñoz et al 2024 Phys. Med. Biol. 69 135004

 

Past Events and Reports

2024 - Progress report 2024

• 8^th General Meeting (Online, December)
  • Discussion on positioning of PP-ICs according to TRS-398, beam monitor calibration intercomparison, and PSQA guideline development
  • ESTRO-EPTN guideline on acquisition of proton beam data published.
     
• 5^th Thematic Workshop (Online, May) – TRS-398 Implementation
  • Resulted in a draft EPTN-WP2 Commentary on TRS-398

 

2023 - Progress report 2023

• 7^th General Meeting (Online, December)
  • Highlights PSQA Workshop, beam monitor calibration intercomparison and ESTRO/EPTN guideline on beam data collection in development
     
• 4^th Thematic Workshop – Patient-Specific QA (with WP5)
  13–14 October 2023, Torino, Italy (ESTRO Physics Workshop)
  "Towards a consensus on pre-treatment verification in particle therapy"

 

2022 - Progress report 2022

• 6^th General Meeting (Online, December)
  • New beam quality correction factors for ICs, Review of LET campaign, PSQA ESTRO physics workshop planning and update on ESTRO/EPTN guideline on beam data collection.
     
• 3^rd Thematic Workshop – TRS-398 Update
  ​April 2022, DCPT, Aarhus, Denmark
  • 3-day event: discussions on TRS-398 update draft
     
• 5^th General Workshop (Online, February)
  • Progress updates, planning for Aarhus TRS-398 workshop and proposal for ESTRO/EPTN guideline on beam data collection.
  • Support of LET measurement campaign with DCPT & EURADOS WG9.

 

2021 - Progress report 2021

• 2^nd Thematic Workshop (Online, May) – Ultra-High Dose Rate (FLASH) Dosimetry
  • Covered detectors, beam calibration, and preclinical experimental setups.

 

2020 - Progress report 2020

• 4^th General Workshop (Online, December)
  • Focus on INSPIRE-supported dosimetry projects (NPL), and TRS-398 updates.

 

2019 - Progress report 2019

• 1^st Thematic QA Workshop – Quality assurance in proton therapy
  23–24 October 2019, HollandPTC, Delft
  • ​Centers presented QA workflows and challenges, discussion on the survey.
     
• 3^rd General Workshop (Brussels, BE, March)
  • Discussions on QA heterogeneity and absolute dosimetry initiatives.

 

2018 - Progress report 2018

• 2^nd General Workshop (Frankfurt, DE, May)
  • Focus on QA/equipment survey, reference dosimetry, and audits.
  • Preliminary survey results presented at ESTRO 37 (Barcelona, April 2018).

 

2017 - Progress report 2017

• 1^st General Workshop (Brussels, BE, March)
  • Establishment of 6 internal working groups and scope definition

2016 - Progress report 2016

• Definition of aims and structure.

Work Package 3: Education

Coordinators:
Morten Høyer, Denmark
Marco Schwarz, USA
Rita Simoes, UK

Work Package 4: Image guidance

Coordinators:
Markus Stock, Austria
Alessandra Bolsi, Switzerland

Aims:

• Consolidate existing knowledge
  Gather and synthesize information on current clinical experience, guidelines and research related to IGPT to establish a comprehensive understanding of its principles and applications.
• Identify clinical practice parameters and patterns
  Systematically identify clinical practice parameters and patterns regarding IGPT, aiming to standardise treatment protocols, optimise workflows and provide excellence in patient care across institutions.
• Develop evidence-based consensus guidelines
  Systematically collect and review available evidence to formulate evidence-based recommendations for the minimum clinical and technical requirements for IGPT in different cancer types, treatment settings and patient populations.
• Facilitate collaborative research
  Stimulate collaboration among researchers and institutions to conduct high-quality multicentric studies aimed at advancing the understanding and refining the practice of IGPT, with the aim to standardise treatment protocols, optimise workflows and improve treatment outcomes.
• Promote education and awareness
  Foster education and awareness among all professional sub-disciplines about the appropriate utilisation of IGPT through the organisation of the annual workshop and the dissemination of practice patterns and consensus guidelines.

Organisation:

The “Image Guidance” work package has the following body-site specific sub-working groups (in alphabetical order):

• Abdominal tumours
  Sub-working group Leader: Markus Stock (AT)
• Brain tumours
  Sub-working group Leaders: Iuliana Toma-Dasu (SE), Dante Amelio (IT)
• CSI tumours
  Sub-working group Leaders: Petra Trnková (CZ), Alessandra Bolsi (CH)
• Extremity tumours
  Sub-working group Leaders: Lorenzo Placidi (IT), Alessandra Bolsi (CH), Juliette Thariat (FR)
• Head and neck tumours
  Sub-working group Leader: Juliette Thariat (IT)
• Pelvic tumours
  Sub-working group Leaders: Markus Stock (AT), Christian Reschl (AT)
• Thoracic tumours
  Sub-working group Leader: Alexandru Dasu (SE)

Projects:

• Comprehensive evaluation of inter- and intrafraction accuracy of immobilization devices used for image-guided particle radiation therapy: a multicenter study

Study Managers: Amelio Dante (IT), Daniele Scartoni (IT)

Description: here

Events:

The “Image Guidance” work package organises an annual event to discuss ongoing activities related to the aforementioned aims of the work package.

• Past workshops

2025: Maastro, Maastricht (NL) - EPTN WP2/WP4-EURADOS Joint workshop
Part 1: Workshop on Out-of-field Dosimetry in Proton Therapy: Translation to Clinical Practice with a Focus on Pregnant Patients (21 February; online)
Part 2: Workshop on Out-of-field Dosimetry in Proton Therapy: Translation to Clinical Practice with a Focus on Pregnant Patients (10 and 11 March; live in Maastricht)

2024: HollandPTC, Delft (NL) - Progress report

2023: Skandionkliniken, Uppsala (SE) - Progress Report 2023

2022: MedAustron, Wiener Neustadt (AT) - Progress Report 2022

2021: virtual meeting                  

2020: virtual meeting - Progress Report 2020

2019: Centro di Protonterapia, Trento (IT) - Progress Report 2019

2018: Proton Therapy Center Czech, Prague (CZ) - Progress Report 2018

2017: University ProtonTherapy Dresden, Dresden (DE) - Progress Report 2017

2016 : Progress Report 2016

News:

• Abstract presentation at PTCOG63
  Image Guided Proton Therapy of Head and Neck Tumours, Practise Survey of the EPTN WP4
  • Thariat P, Louwe R, Bäumer C, Baker C, Comi S, Goedgebeur A, Jensen K, Kedzierska-Pardel D, Lowe M, Pisciotta P, Troost E, Vallhagen Dahlgren C, Vidal M, Vitek P, Widesott L, Hoffmann A, Bolsi A.

 

• Publications
  • Trnková P, Dasu A, Placidi L, Stock M, Toma-Dasu I, Brouwer CL, Gosling A, Jouglar E, Kristensen I, Martin V, Moinuddin S, Pasquie I, Peters S, Pica A, Plaude S, Righetto R, Rombi B, Thariat J, van der Weide H, Hoffmann A, Bolsi A. Patterns of practice of image guided particle therapy for cranio-spinal irradiation: A site specific multi-institutional survey of European Particle Therapy Network. Physica Medica 2024; 123: 103407. doi: 10.1016/j.ejmp.2024.103407
  • Bolsi A, Peroni M, Amelio D, Dasu A, Stock M, Toma-Dasu I, Nyström PW, Hoffmann A. Practice patterns of image guided particle therapy in Europe: A 2016 survey of the European Particle Therapy Network (EPTN). Radiother Oncol 2018; 128(1): 4-8. doi: 10.1016/j.radonc.2018.03.017.

Work Package 5: Treatment planning

Mission
This work package is dedicated to all aspects of treatment planning in particle therapy. It addresses the need for standardization, consensus finding and guidelines for routine clinical application as well as for implementation of new methods and technologies across centers in Europe.

Organisation
The “Treatment planning” work package has the following subgroups:

Subgroup	Subgroup coordinators
Planning standards & Planning studies	Tony Lomax (CH)
Commissioning	Xavier Vermeren (GER)
Patient-specific QA	Tony Lomax (CH)
CT calibration	Vicki Taasti (DK)
Plan robustness	Edmond Sterpin (BEL) Francesco Fracchiolla (IT)
4D treatment planning	Ilaria Rinaldi (NL) Sabine Visser
LET/RBE	Dirk Wagenaar (NL)
Autoplanning	Anne Lisa Wolf (NL)

 

If you want to become active in any of those subgroups, please contact the respective subgroup coordinators.

Furthermore, WP5 is deeply involved in cross-work package activities in EPTN. The most important ones are listed here:

Cross-WP activity	Together with WP	WP5 Liaison person
EPTN Adaptive Task Group – Initiated in 2023	WP1, WP2, WP4	Francesca Albertini (CH)
Development of PSQA Consensus	WP2	Tony Lomax (CH)
QA of imaging in adaptive workflows – Workshop 2025	ATG, WP4	Christian Richter (GER)
Consensus on LET/RBE considerations – Workshop 2023 (Beyond Physical Dose)	WP1, WP6	Dirk Wagenaar (NL)

 

Publications with involvement of WP5

• Sterpin et al. Robustness evaluation of pencil beam scanning proton therapy treatment planning: A systematic review. Radiother Oncol 197, 110365, 2024
• Peters et al. Consensus guide on CT-based prediction of stopping-power ratio using a Hounsfield look-up table for proton therapy. Radiother Oncol 184, 109675, 2023
• Trnkova et al. A survey of practice patterns for adaptive particle therapy for interfractional changes. phiRO  26, 100442, 2023
• Zhang et al. A survey of practice patterns for real-time intrafractional motion-management in particle therapy. phiRO  26, 100439, 2023
• Knopf et al. Clinical necessity of multi-image based (4DMIB) optimization for targets affected by respiratory motion and treated with scanned particle therapy - A comprehensive review. Radiother Oncol 169, 77-85, 2022
• Peters et al. Experimental assessment of inter-centre variation in stopping-power and range prediction in particle therapy. Radiother Oncol 163, 7-13, 2021

Coordinators
Tony Lomax, Switzerland, tony.lomax@psi.ch
Christian Richter, Germany, christian.richter@oncoray.de

Work Package 6: Radiobiology

Coordinators
Brita Sørensen, Denmark
Armin Lühr, Germany

Organisation
The “Radiobiology” work package has the following subgroups:

Subgroup	Subgroup coordinators
Experimental	Brita Sørensen (DK) Elke Beyreuther (GER)
Modelling	Thomas Friedrich (GER) Bleddyn Jones (UK)
Clinical	Armin Lühr (GER) Peter van Luijk (NL) Thomas Tessonnier (GER)

 

How to contribute?
If you want to become active in any of those subgroups, please contact the respective subgroup coordinators.

Upcoming Symposium: Pre-clinical Ion Beam Research

Join us at the Vienna Biocenter on 17–18 December for a student-organised symposium focused on pre-clinical ion beam research, exploring key topics in oncology, radiobiology, and physics.

The event is free to attend. The preliminary programme, registration, and abstract submission details are available on the official website:
👉 www.pairsymposium.com

Work Package 7: Health economy - HTA

Coordinator:
Yolande Lievens, Belgium

Work Package 8: Data registry infrastructure

Coordinators:
Esther Troost, Germany
Vincent Gregoire, France

EPTN Reports

EPTN Reports

• EPTN Report 2024
• EPTN Report 2023
• EPTN Report 2022
• EPTN Report 2021
• EPTN Report 2020
• EPTN Report 2019
• EPTN Report 2018
• EPTN Report 2017
• EPTN Report 2016

EPTN Documents

• WP5 PTPS specifications

EPTN Publications

• The posterior cerebellum, a new organ at risk?

• Prospective data registration and clinical trials for particle therapy in Europe

• Optimizing clinical research and generating prospective high-quality data in particle therapy in Europe: Introducing the European Particle Therapy Network (EPTN)

• ULICE Collaborative Research Group. Union of light ion therapy centers in Europe (ULICE EC FP7) - Objectives and achievements of joint research activities

• Proton therapy for pediatric malignancies: Fact, figures and costs. A joint consensus statement from the pediatric subcommittee of PTCOG, PROS and EPTN

• Overview of research and therapy facilities for radiobiological experimental work in particle therapy. Report from the European Particle Therapy Network radiobiology group

• ENLIGHT: European network for Light ion hadron therapy

• Practice patterns of image guided particle therapy in Europe: A 2016 survey of the European Particle Therapy Network (EPTN)

• “European Particle Therapy Network” of ESTRO. The EPTN consensus-based atlas for CT- and MR-based contouring in neuro-oncology

• Bringing Europe together in building clinical evidence for proton therapy - the EPTN-ESTRO-EORTC endeavor

• Proton therapy and the European Particle Therapy Network: The past, present and future

• Particle therapy in Europe

• Update of the EPTN atlas for CT- and MR-based contouring in Neuro-Oncology

• Does the uncertainty in relative biological effectiveness affect patient treatment in proton therapy?

• Is a variable proton RBE considered in clinical practice? - ESTRO survey among 25 proton centres

• Does the uncertainty in relative biological effectiveness affect patient treatment in proton therapy?

• Update of the EPTN atlas for CT- and MR-based contouring in Neuro-Oncology

• The European particle therapy network (EPTN) consensus on the follow-up of adult patients with brain and skull base tumours treated with photon or proton irradiation

• Clinical use and future requirements of relative biological effectiveness: Survey among all European proton therapy centres

• Development of explanatory movies for the delineation of new organs at risk in neuro-oncology

• Development and evaluation of an automated EPTN-consensus based organ at risk atlas in the brain on MRI

• A year of pandemic for European particle radiotherapy: A survey on behalf of EPTN working group

• Clinical use and future requirements of relative biological effectiveness: Survey among all European proton therapy centres

• Clinical necessity of multi-image based (4D_MIB) optimization for targets affected by respiratory motion and treated with scanned particle therapy - A comprehensive review

• The European Particle Therapy Network (EPTN) consensus on the follow-up of adult patients with brain and skull base tumours treated with photon or proton irradiation

• Geometric and dosimetric analysis of CT- and MR-based automatic contouring for the EPTN contouring atlas in neuro-oncology

• Towards a European prospective data registry for particle therapy

• ESTRO-EPTN radiation dosimetry guidelines for the acquisition of proton pencil beam modelling data