Octávia Monteiro Gil, Ursula Oestreicher, Rositsa Histova, Olga Sevriukova, Laure Bobyk, Yoann Ristic, Antonella Testa, Juan S. Martinez, Clemens Woda, Alfredo Hernandez, Ulrike Kulka, Lovisa Waldner, Eric Gregoire, Georgia I. Terzoudi, Elizabeth A. Ainsbury, Sotiria Triantopoulou, Alegría Montoro, Mirta Milić, Joan Francesc Barquinero, Andrzej Wojcik, Anne Vral, Katalin Lumniczky, David Endesfelder, Sylwester Sommer, Laure Sabatier, François Trompier, Clarice Patrono, M. Valente, Rita Hargitai, Stephen Barnard, Christina Beinke, Mercedes Moreno Domene, Jayne Moquet, María Jesús Prieto, Bundesamt für Strahlenschutz (BfS), Federal Office for Radiation Protection (BfS), Public Health England (PHE), Public Health England, Centre for Radiation Chemical and Environmental Hazards (PHE), PSE-SANTE/SERAMED/LRAcc, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-SANTE/SDOS/LDRI, Institute of Radiation Medicine, Helmholtz Zentrum München, Lund University and Lund University Hospital, Bundeswehr Institute of Radiobiology affiliated to the University of Ulm (BIR), Universiteit Gent, Universitat Autonoma de Barcelona, Institute of Nuclear Chemistry and Technology (INCT), National Research Institute for Radiobiology & Radiohygiene, National Public Health Centre, Fundación para la Investigación del Hospital Universitario LA FE de la Comunidad Valenciana (LA FE), IMROH, Instituto Superior Técnico, IRBA, Radiation Protection Centre, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Hospital General Universitario Gregorio Marañon, Servicio Madrileño de Salud - Hospital General Universitario Gregorio Marañón (SERMAS), Agenzia Nazionale per le Nuove Tecnologie, L’energia e lo Sviluppo Economico Sostenibile, National Center for Scientific Research 'Demokritos' (NCSRD), National Centre for Scientific Research ‘Demokritos’, National Centre of Radiobiology and Radiation Protection, Stockolm University (SU), Bundesamt für Strahlenschutz - Federal Office for Radiation Protection (BfS), Laboratoire de Radiobiologie des expositions accidentelles (IRSN/PSE-SANTE/SERAMED/LRAcc), Service de recherche en radiobiologie et en médecine régénérative (IRSN/PSE-SANTE/SERAMED), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire de dosimétrie des rayonnements ionisants (IRSN/PSE-SANTE/SDOS/LDRI), Service de dosimétrie (IRSN/PSE-SANTE/SDOS), Lund University [Lund], Universität Ulm - Ulm University [Ulm, Allemagne], Universiteit Gent = Ghent University (UGENT), Universitat Autònoma de Barcelona (UAB), and Stockholm University
Purpose: Depending on the exposure scenario, different biological and/or physical assays will be required to recover the exposure situation and to obtain reliable dose estimates to aid medical decision making. Inter-laboratory comparisons (ILCs) are a central tool to validate and improve the performance of methods and laboratories. In most cases such ILCs are performed under laboratory conditions where the influence of parameters contributing to uncertainties can be minimized. In a reallife scenario, the situation is much more complicated, and it is therefore crucial to validate methods and laboratories’ abilities to carry out these methods under more realistic conditions. In 2019, EURADOS (The European Radiation Dosimetry Group) Working Group 10 (Retrospective Dosimetry) and RENEB (Running the European Network of Biological and retrospective Physical dosimetry) organized a field exercise in Lund, Sweden, to validate different methods for biological and physical retrospective dosimetry in parallel by simulating real- life exposure scenarios. Materials and methods: For the dicentric chromosome assay (DCA), 18 blood tubes were distributed across 8 thermos flasks filled with heated water and positioned at the hips and shoulders of anthropomorphic phantoms in different geometries. Two irradiations were performed with a 1.36 TBq 192Ir-source, each with two phantoms, to simulate close, distant, lateral or partially shielded exposures. For each of the blood tubes DCA dose estimates were provided by at least one laboratory and for tubes from four thermos flasks by 17 participating RENEB laboratories. In addition, blood from the different thermos flasks on each phantom was mixed to simulate heterogeneous exposures. Three radio-photoluminescence (RPL) glass dosimeters (GD) were placed at each tube to assess reference doses and the inter- and intra-tube variability. Results: The results from the DCA were homogeneous between participants and matched well with RPL GD reference doses (≥95% of estimates within ±0.5 Gy of the reference). For samples close to the source, exposed to doses >1 Gy, systematic underestimation could be corrected by accounting for exposure time. Heterogeneity within and between tubes was detected for RPL GD reference doses as well as for doses estimates from the DCA. The sample simulating a heterogeneous exposure with two different doses was detected by ~50% of the participants. Conclusions: The participants were able to successfully estimate the doses and to provide important information on the exposure scenarios under conditions closely resembling a real-life situation. The reliability of the results emphasizes the value of the DCA for retrospective dosimetry under field conditions.