Copenhagen, Denmark

ESTRO 2022

Session Item

Brachytherapy: Physics
Poster (digital)
Primary standards and measurement methods for X-ray emitting electronic BT devices PRISM-eBT
Thorsten Schneider, Germany


Primary standards and measurement methods for X-ray emitting electronic BT devices PRISM-eBT

Thorsten Schneider1, Rolf Behrens1, Fernando Garcia-Yip2, Kari Tanderup3, Gustavo Kertzscher4, Jacob Johanson4, Peter Georgi4, Valentin Blideanu5, Christel Stien6, Johann Plagnard7, Jaroslav Solc8, Vladimir Sochor9, Massimo Pinto10, Thorsten Sander11, Anna Subiel11, Clare Gouldstone11, Leon de Prez12, Frank Verhaegen13, Brigitte Reniers14, Paz Avilés Lucas15, Zakithin Msimang16, David J Eaton17, Frank Weigand18, Mark J. Rivard19

1Physikalisch-Technische Bundesanstalt (PTB), Dosimetry for Brachytherapy, Braunschweig, Germany; 2Physikalisch-Technische Bundesanstalt (PTB), Dosimetry for Brachytherapy , Braunschweig, Germany; 3Aarhus University Hospital, Radiation Therapy, Aarhus, Denmark; 4Aarhus University Hospital, Radiation Therapy , Aarhus, Denmark; 5Commissariat à l’énergie atomique et aux énergies alternatives, CEA, Paris, France; 6Commissariat à l’énergie atomique et aux énergies alternatives, CEA , Paris, France; 7Commissariat à l’énergie atomique et aux énergies alternatives , CEA , Paris, France; 8Cesky Metrologicky Institut, CMI, Brno, Czech Republic; 9Cesky Metrologicky Institut, CMI , Brno, Czech Republic; 10Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA), Istituto Nazionale di Metrologia delle Radiazioni ionizzanti, Casaccia, Italy; 11NPL Management Limited, NPL, Teddington, United Kingdom; 12VSL B.V., VSL, Delft, The Netherlands; 13Stichting Maastricht Radiation Oncology Maastro Clinic , MAASTRO clinic, Maastricht, The Netherlands; 14Hasselt University, Universiteit Hasselt , Diepenbeek, Belgium; 15National Metrology Institute of Spain, LMRI-CIEMAT, Madrid, Spain; 16International Atomic Energy Agency, IAEA, Wien, Austria; 17 Guy’s and St Thomas’ Hospitals, London, United Kingdom & School of Biomedical Engineering & Imaging Sciences, King’s College London, Department of Medical Physics, London, United Kingdom; 18Carl Zeiss Meditec AG, Meditec, Oberkochen, Germany; 19Brown University, Dept. Radiation Oncology, Providence, RI,, USA

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Purpose or Objective

Within the framework of the European Metrology Programme for Innovation and Research (EMPIR), six European National Metrology Institutes (NMIs) together with four additional partners from universities and clinics are collaborating in a Joint Research Project PRISM-eBT to establish a harmonised, simplified, and traceable dosimetry for electronic brachytherapy (eBT) in terms of absorbed dose to water.

Material and Methods

The project is composed of four Workpackages (WP):

WP1’s aim is to establish primary standards for the absorbed dose rate to water for eBT devices at 1 cm depth in water, and to establish transfer instruments and corresponding measurement procedures for the dissemination of this quantity to clinical practice.

In WP2, a dosimetric methodology for skin eBT is being established with traceability to a primary standard developed in WP1.

In WP3, detectors and measurement instruments suitable for the determination of 3D dose distributions in water by eBT devices are characterised to develop a standardised traceable calibration process.

With these detectors, traceable dosimetry to determine 3D dose distributions in water is being established in WP4 to provide availability for the end-user community.


Established primary standards, methodologies for traceability, and detectors characterization are highlighted and discussed in the presentation.
E.g. a catalogue of eBT and eBT-equivalent X-ray photon fluence spectra was compiled from data available in literature, obtained from manufacturers, and measured or created during the project. The catalogue is available on the project website and it provides a basis for spectrometry and dosimetry of eBT sources. Using a plastic scintillator detector, the dose profile and depth-dose curve for an eBT source were determined with a precision better than 2.5%. It will be discussed which methods have proven to be successful and which methods were withdrawn from additional consideration.


An outlook will be given which further results might be achieved by the end of the project at the end of 2022.

This project 18NRM02 PRISM-eBT has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.