EURADOS intercomparisons on whole-body dosemeters for photons from 2008 to 2020: analysis and comparison of general results.

Starting in 2008 the European Dosimetry Group (EURADOS) has been performing international intercomparisons (ICs) on photon whole-body dosemeters for individual monitoring services. These ICs have been organized (on a biennial basis) starting 2008 up to 2020 now, each time with a similar set-up but with small alterations in the subsequent irradiation plans. The response for Hp(10) and Hp(0.07) was tested for different radiation qualities, angles of incidences (0°-60°) within a wide range of dose values (0.5-500 mSv), to check energy and angular response, linearity, reproducibility and mixed-field response. Within the last 12 years almost 15 000 whole body dosemeters have been irradiated and the corresponding response values evaluated. With an increasing number of participants and participating systems (from 62 to 132), this IC program has become an important tool for individual monitoring services to test their whole-body dosimetry systems, compare their results with other services or systems and to improve the quality of their dosimetry. The paper presents and compares the general results of these seven ICs and analyses the dosimetric results for the participating system types.

EURADOS whole-body dosemeters intercomparisons: lessons learnt from individual results.

Every 2 years since 2008, Eurados WG2 has organised a whole-body dosemeters intercomparison (IC) in photon and beta fields. This paper presents the information that individual participants can extract from their results. The irradiation plan of each IC was designed to allow participants check the performance of some important characteristics of their dosimetry systems, in particular: linearity, angular response, energy response and response to mixed fields. The analysis of anomalous responses indicates that many systems can reduce the number of outliers by improving their calibration procedures.

EURADOS IC2019exteye- a self-funded intercomparison for extremity and eye lens dosemeters organised by EURADOS working group 2.

The European Radiation Dosimetry Group (EURADOS) has been organising regular, self-funding, external dosimetry intercomparisons (ICs) since 2008. IC2019exteye, for extremity and eye lens dosemeters, attracted 113 systems (68 extremity and 45 eye lens) from 60 institutes with participants from 26 countries around the world. Irradiations were carried out in accredited European irradiation facilities in terms of Hp(0.07)/or Hp(3) in the ranges: photon energy: 16-662 keV, beta mean energy 250-1000 keV, dose: 0.5 mSv to 1 Sv, maximum angle of incidence: ±60°. This paper describes the IC2019exteye set-up, irradiation plan and coordination with an overview of the main conclusions. Out of the total of 113 systems, 57 reported results for photons only and 56 reported both photon and beta. In general, the participants showed very satisfactory performances with the medians of all Hp(0.07) and Hp(3) response values very close to unity.

EURADOS intercomparison IC2020ph on whole body dosemeters for photons.

The European Dosimetry Group has been organising international intercomparisons (ICs) for personal dosemeters on a regular basis. The IC announced in 2020 was postponed to the end of 2020 and the beginning of 2021 due to coronavirus (COVID-19) restrictions. The irradiation plan consisted of nine irradiation setups with five different photon radiation qualities (S-Cs, S-Co, N-150, W-60, W-80) and two different angles of irradiation incidence (0o and 60o). A total of 112 monitoring services from 50 countries with 132 dosimetry systems participated. The present work describes and analyses the individual results for the personal dose equivalent quantities Hp(10) and, if submitted, Hp(0.07) for all participating systems. It also presents the organisational details and the difficulties arising from the COVID-19 crisis during the IC. The statistical results showed a satisfactory performance with the medians of all Hp(10) and Hp(0.07) response values very close to unity. However, there are few individual monitoring services with significant large variations.

RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA).

PURPOSE: Two quality controlled inter-laboratory exercises were organized within the EU project 'Realizing the European Network of Biodosimetry (RENEB)' to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network. MATERIALS AND METHODS: The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants. RESULTS: The shipment of blood samples to the partners in the European Community (EU) were performed successfully. Outside the EU unacceptable delays occurred. The results of the dose estimation demonstrate a very successful classification of the blood samples in medically relevant groups. In comparison to the 1st exercise the 2nd intercomparison showed an improvement in the accuracy of dose estimations especially for the high dose point. CONCLUSIONS: In case of a large-scale radiological incident, the pooling of ressources by networks can enhance the rapid classification of individuals in medically relevant treatment groups based on the DCA. The performance of the RENEB network as a whole has clearly benefited from harmonization processes and specific training activities for the network partners.

EURADOS INTERCOMPARISONS ON WHOLE-BODY DOSEMETERS FOR PHOTONS FROM 2008 TO 2014.

Starting in 2008 the European Dosimetry Group (EURADOS) has been performing international intercomparisons on photon whole-body dosemeters for individual monitoring services. These intercomparisons were organised (on a biannual basis) in 2008, 2010, 2012 and 2014, each time with a similar set-up but with small alterations in the subsequent irradiation plans. With an increasing number of participants and participating systems, this intercomparison action has become an important tool for individual monitoring services to test their whole-body dosimetry systems, compare their results with other services or systems and to improve the quality of their dosimetry. The paper presents and compares the results of these four intercomparisons and compares the dosimetric results for the participating system types. Major dosimetric problems of the individual monitoring services are identified, and trends in the dosimetric performance of the different systems are shown. This gives the opportunity to identify some dosimetry issues that should be improved by application of the monitoring services' quality assurance systems and QA procedures.

EURADOS INTERCOMPARISONS IN EXTERNAL RADIATION DOSIMETRY: SIMILARITIES AND DIFFERENCES AMONG EXERCISES FOR WHOLE-BODY PHOTON, WHOLE-BODY NEUTRON, EXTREMITY, EYE-LENS AND PASSIVE AREA DOSEMETERS.

The European Radiation Dosimetry Group (EURADOS) has been organising dosimetry intercomparisons for many years in response to an identified requirement from individual monitoring services (IMS) for independent performance tests for dosimetry systems. The participation in intercomparisons gives IMS the opportunity to show compliance with their own quality management system, compare results with other participants and develop plans for improving their dosimetry systems. In response to growing demand, EURADOS has increased the number of intercomparisons for external radiation dosimetry. Most of these fit into the programme of self-financing intercomparisons for dosemeters routinely used by IMS. This programme is being coordinated by EURADOS working group 2 (WG2). Up to now, this programme has included four intercomparisons for whole-body dosemeters in photon fields, one for extremity dosemeters in photon and beta fields, and one for whole-body dosemeters in neutron fields. Other EURADOS working groups have organised additional intercomparisons including events in 2014 for eye-lens dosemeters and passive area dosemeters for environmental monitoring. In this paper, the organisation and achievements of these intercomparisons are compared in detail focusing on the similarities and differences in their execution.

Quality control and reliability of reported doses.

Results of performance tests verifying the dosimetric properties of dosimetric systems are published in various reports (e.g. IAEA and EURADOS). However, there is hardly any information in the open literature relating to the uncertainty in a dose measurement or in the annual dose, which is increased by failure of the evaluation or data management system, damage of the dosemeter itself or by the loss of dosemeter. In this article, an attempt is made to estimate the importance of the above-mentioned conditions. This is achieved by sending questionnaires to about 200 approved dosimetric services in Europe. In total 88 questionnaires were returned and analysed. In the questionnaires, the frequency of occurrence of the various error conditions were investigated. Participants were also asked to evaluate the impact of the error condition from a dosimetric point of view and what countermeasures are taken. The article summarises all responses and compares different sources of errors according to their impact on the uncertainty of the resulting dose and gives a comprehensive overview on quality control actions and reliability on reported doses from European dosimetric services.

Chromosomal radiosensitivity and acute radiation side effects after radiotherapy in tumour patients--a follow-up study.

BACKGROUND: Radiotherapists are highly interested in optimizing doses especially for patients who tend to suffer from side effects of radiotherapy (RT). It seems to be helpful to identify radiosensitive individuals before RT. Thus we examined aberrations in FISH painted chromosomes in in vitro irradiated blood samples of a group of patients suffering from breast cancer. In parallel, a follow-up of side effects in these patients was registered and compared to detected chromosome aberrations. METHODS: Blood samples (taken before radiotherapy) were irradiated in vitro with 3 Gy X-rays and analysed by FISH-painting to obtain aberration frequencies of first cycle metaphases for each patient. Aberration frequencies were analysed statistically to identify individuals with an elevated or reduced radiation response. Clinical data of patients have been recorded in parallel to gain knowledge on acute side effects of radiotherapy. RESULTS: Eight patients with a significantly elevated or reduced aberration yield were identified by use of a t-test criterion. A comparison with clinical side effects revealed that among patients with elevated aberration yields one exhibited a higher degree of acute toxicity and two patients a premature onset of skin reaction already after a cumulative dose of only 10 Gy. A significant relationship existed between translocations in vitro and the time dependent occurrence of side effects of the skin during the therapy period. CONCLUSIONS: The results suggest that translocations can be used as a test to identify individuals with a potentially elevated radiosensitivity.