EURADOS ISO/IEC 17025 guidance for IMS: suggestions on how to interpret and implement the requirements including examples from accredited laboratories.

Individual monitoring of external radiation is an activity usually regulated by national regulatory bodies in most countries. Regulations generally contain technical requirements to be met by the individual monitoring services (IMS), in order to ensure that the measurements are correct and therefore the dosimetry results are reliable. In some countries, the requirements include or even consist of the accreditation of the service according to the standard ISO/IEC 17025: 'General requirements for the competence of testing and calibration laboratories.' It is a fact that accreditation is a growing trend among European IMS as a way to guarantee confidence in their technical competence. The acceptance of the dosimetry results between countries and their indentation in the respective National Dose Registries is facilitated if laboratories conform to the ISO/IEC 17025 standard. In the framework of the activities of EURADOS (European Radiation Dosimetry Group) working group 2 'Harmonization of Individual Monitoring in Europe' and attending to the concern of many European IMS in the process of accreditation, a guide has been prepared. The purpose was to assist and encourage IMS to apply for accreditation and to share the authors' own experience with the process. The guide intends to be a practical reference for IMS on how to interpret and implement the ISO/IEC 17025 requirements to the specific activity of a personal dosimetry service for external radiation, emphasizing those aspects of special interest. It includes examples from dosimetry laboratories already accredited. The major novelties from a new edition of ISO/IEC 17025: 2017 are also identified in the guide. Finally, the guide aims to assist the auditing process, giving examples of auditor's questions and how to show evidence of compliance. The main findings are presented.

Radiation-Induced Lens Opacities among Interventional Cardiologists: Retrospective Assessment of Cumulative Eye Lens Doses.

This study describes the retrospective lens dose calculation methods developed and applied within the European epidemiological study on radiation-induced lens opacities among interventional cardiologists. While one approach focuses on self-reported data regarding working practice in combination with available procedure-specific eye lens dose values, the second approach focuses on the conversion of the individual whole-body dose to eye lens dose. In contrast with usual dose reconstruction methods within an epidemiological study, a protocol is applied resulting in an individual distribution of possible cumulative lens doses for each recruited cardiologist, rather than a single dose estimate. In this way, the uncertainty in the dose estimate (from measurement uncertainty and variability among cardiologists) is represented for each individual. Eye lens dose and whole-body dose measurements have been performed in clinical practice to validate both methods, and it was concluded that both produce acceptable results in the framework of a dose-risk evaluation study. Optimal results were obtained for the dose to the left eye using procedure-specific lens dose data in combination with information collected on working practice. This method has been applied to 421 interventional cardiologists resulting in a median cumulative eye lens dose of 15.1 cSv for the left eye and 11.4 cSv for the right eye. From the individual cumulative eye lens dose distributions obtained for each cardiologist, maxima up to 9-10 Sv were observed, although with low probability. Since whole-body dose values above the lead apron are available for only a small fraction of the cohort and in many cases not for the entire working career, the second method has only been used to benchmark the results from the first approach. This study succeeded in improving the retrospective calculation of cumulative eye lens doses in the framework of radiation-induced risk assessment of lens opacities, but it remains dependent on self-reported information, which is not always reliable for early years. However, the calculation tools developed can also be used to make an assessment of the eye lens dose in current practice.

A Holistic Approach to Assessment of Population Exposure to Radiation: Challenges and Initiatives of a Regulatory Authority.

A regulatory authority for radiation safety should continuously evaluate and improve the national safety framework, in line with current requirements and standards. In this context, the Greek Atomic Energy Commission initiated a series of concerted actions. The radiation dose to the population due to public and medical exposures was assessed. The assessment of dose due to public exposure was based on measurements of radon concentrations in dwellings, radionuclide concentrations in environmental samples, and air dose rates; the assessment of dose due to medical exposure was based on dose measurements for typical examinations or procedures and data on their frequency. The mean effective dose to a member of the population was found to be 4.5 mSv (1.8 mSv and 2.7 mSv from medical and public exposures, respectively). Regarding occupational exposure, aircrew dose assessment, eye lens monitoring, and the national dose registry were significantly improved. With respect to artificial tanning (sun beds), the ultraviolet radiation produced was assessed and the practices followed were observed. Results demonstrated exceedance of the 0.3 W m erythema effective irradiance limit set in European Union standards by 63.5% of the sun beds measured, along with general noncompliance with standards. An overarching activity was the upgrade of the Greek Atomic Energy Commission information system in order to collect and disseminate radiation data electronically, launch a networking strategy for interaction with stakeholders, and facilitate the process of regulatory control. In response to the above findings, regulatory actions have been initiated.

The deconvolution of thermoluminescence glow-curves using general expressions derived from the one trap-one recombination (OTOR) level model.

The new developed thermoluminescence (TL) glow-peak expressions derived from the one trap-one recombination (OTOR) level model were used to analyze the TL glow-curves recorded with linear and exponential heating function profiles under various experimental conditions. The results showed that these expressions can, accurately, analyze the TL glow-curves even with the overlapped glow-peaks. Low values of R=An/Am were reported for glow-peaks in different TL materials. A glow-peak with the possibility of An>Am was also pointed out.

Quality assurance and quality control programme in the Personal Dosimetry Department of the Greek Atomic Energy Commission.

A quality assurance (QA) and quality control (QC) programme was applied to the personal monitoring department (TLD based) of the Greek Atomic Energy Commission (GAEC). This programme was designed according to the recommendations of international bodies such as the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), the International Atomic Energy Agency (IAEA) and the European Commission (CEC). This paper deals with the presentation of the QA/QC programme which includes administrative data and information, technical checking of the equipment, acceptance tests of new equipment and dosemeters, issuing and processing of the dosemeters, dose evaluation, record keeping and reporting, traceability and reproducibility, handling of complaints, internal reviews and external audits.

Pre- and post-irradiation fading effect for LiF:Mg,Ti and LiF:Mg,Cu,P materials used in routine monitoring.

LiF is a well-known thermoluminescent (TL) material used in individual monitoring, and its fading characteristics have been studied for years. In the present study, the fading characteristics (for a period of 150 d) of various commercial LiF materials with different dopants have been evaluated. The materials used in the study are those used in routine procedures by the Personal Dosimetry Department of Greek Atomic Energy Commission and in particular, LiF:Mg,Ti (MTS-N, TL Poland), LiF:Mg,Cu,P (MCP-N, TL Poland), LiF:Mg,Cu,P (MCP-Ns, thin active layer detector, TL Poland) and LiF:Mg,Cu,P (TLD100H, Harshaw). The study showed that there is a sensitivity loss in signal of up to 20 % for the MTS-N material for a 150-d period in the pre-irradiation fading phase. The MCP-N has a stable behaviour in the pre-irradiation fading phase, but this also depends on the readout system. As far as the post-irradiation fading effect is concerned, a decrease of up to 20 % for the MTS-N material is observed for the same time period. On the other hand, the LiF:Mg,Cu,P material presents a stable behaviour within ± 5 %. These results show that the fading effect is different for each material and should be taken into account when estimating doses from dosemeters that are in use for >2 months.