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Internal dose assessment intercomparison exercises are useful tools: to verify the performance of an Internal Dosimetry Service; to promote the harmonization of dose assessments; and to identify weaknesses where further improvements are necessary. However, no such international inter-comparisons have been performed for more than 10 years. In the period May 2014 - May 2016, the "Technical Recommendations for Monitoring Individuals for Occupational Intakes of Radionuclides" were developed at the initiative of the European Commission, and later published within the EC Radiation Protection series, as RP 188. In 2017 the Working Group "Internal Dosimetry" of the European Radiation Dosimetry Group (EURADOS) organised a new intercomparison action, named ICIDOSE 2017, with the main aim of testing the practical applicability of these Technical Recommendations (RP188). Four case-studies were proposed to participants: an artificially created case of inhalation of 60Co to simulate a simple special monitoring case; a real case of inhalation of 125I, with simple routine monitoring; a real and more complex case of incorporation of 234+235+238U, featuring both confirmatory and special monitoring; and a complex real case of an accidental incorporation of 241Am, including multiple administrations of DTPA. Results were received from 66 participants from 26 countries; these were compared to reference or recommended solutions, developed for each case based on the application of RP 188. The results were discussed at a workshop in October 2018, at the Federal Office for Radiation Protection (BfS, Munich, Germany). The observed spread of the submitted results was improved from those obtained from similar cases in previous intercomparison exercises, showing that the availability of RP 188 significantly contributes to the harmonization of the internal dose assessment process.

In a nuclear or radiological accident scenario, where members of the public can potentially take up anthropogenic radionuclides released in atmosphere, verified methods to fast screen for internal contamination a large number of individuals directly on the field can play a major role to adopt appropriate countermeasures. At the ENEA Casaccia Research Centre (Rome, Italy), a spectrometric monitoring method, based on a portable HpGe detector Trans-Spec-DX-100, has been developed. In this work, the results of the 2019 measurement campaign, where the method sensitivity was tested, in terms of detection limits (DL) for common fission and (some) activation products by acquiring gamma spectra on 102 uncontaminated volunteers (57 adults, 45 children between 7 and 12 years of age) are presented. The spectra, collected with acquisition time of 180 s, have been analysed according to the Standard ISO 28218 for the activity detection limit (Bq) calculations and according to ICRP Publications 134, 137, and 141 for the related minimum measurable committed effective dose. The measurements were taken in open field on a paved surface, in the presence of an environmental radiation background, given in term of ambient dose equivalent rate, $$\dot{H}$$ H ˙ *(10), equal to 0.230 ± 0.020 μSv/h, in order to study both the potentiality and the limitation of the technique with a significant statistic. The results are presented and discussed particularly focusing on the specific characteristics of the technique, in respect to features reported by the European Council Directive 2013/59/Euratom and the International Atomic Energy Agency (IAEA) document STI/PUB/1708 (2015), and to techniques described in the current literature.

The results obtained in a measurement campaign concerning internal contamination by the gamma-emitting radionuclides of a large number of individuals are presented in this work. The aim is to assess the effectiveness of the spectrometric method in an emergency response following a nuclear power plant accident or a spread of radionuclides in the atmosphere due to an act of terrorism. An HPGe portable spectrometer, deployed in a collective protection apparatus, was used for both whole-body and thyroid measurements. An adult bottle mannequin absorption (BOMAB) and thyroid phantoms were used to evaluate the detector performance. The BOMAB phantom was provided by the Italian Institute of Ionizing Radiation Metrology (INMRI) for the ENEA intercomparison exercise. Thyroid phantoms were provided by the Belgian Nuclear Research Centre for the 'Child and Adult Thyroid Monitoring After Reactor Accident' European intercomparison exercise. The instrument performance was further evaluated by collecting spectral data from healthy volunteers, using acquisition times of 180 s and 100 s, respectively, for the whole-body and thyroid measurements. The detector showed good accuracy in quantifying radionuclide activities in the adult BOMAB and in the thyroids of persons of all ages. The proposed method allows us to detect in vivo activity leading to a committed effective dose E(50) and committed thyroid equivalent doses H T greater than 2 mSv due to all gamma-emitting fission products, if the scan is performed within five days after intake. Assuming, for instance, an acute inhalation of 137Cs and 131I, the obtained detection limit values for adults lead to a E(50) value equal to 0.08 mSv and an H T value of 0.27 mSv. The E(50) and H T values show that the proposed method can be successfully used when the dose assessment must be rapidly performed for a large number of individuals in the eventuality of the scenarios previously mentioned.

In order to properly respond to an emergency caused by an accident in a nuclear power plant with a spread of radionuclides in the atmosphere, we propose a field procedure to perform a large-scale individual thyroid monitoring of internal contamination due to inhalation of 131I, by means of non-spectrometric equipment, in particular dose rate meters. Specific attention is paid to the individual monitoring of children, because of the very high radiosensitivity of the child's thyroid to the carcinogenic effects of ionising radiation. The device performance was evaluated by measuring mock iodine sources provided in the Child and Adult Thyroid Monitoring After Reactor Accident (CAThyMARA) intercomparison and, just for a scintillator dose rate meter, by means of 60 s acquisitions of healthy volunteers' thyroids. All the devices showed a remarkable accuracy in quantification of equivalent 131I activity in the thyroids of persons of all ages. The selected scintillator dose rate meter showed detection limit values resulting in a maximum committed equivalent dose to thyroid HT, assuming an acute 131I inhalation occurred five days before the measurement, equal to 10 mSv (related to five-year-old children). Considering the level of HT values associated with the calculated detection limit activities, the proposed procedure has a significant sensitivity to be used for fast internally thyroid monitoring in nuclear or radiological emergencies, allowing daily monitoring a large amount of individuals.

International audience; European Radiation Dosimetry Group (EURADOS) Working Group 7 is a network on internal dosimetry that brings together researchers from more than 60 institutions in 21 countries. The work of the group is organised into task groups that focus on different aspects, such as development and implementation of biokinetic models (e.g. for diethylenetriamine penta-acetic acid decorporation therapy), individual monitoring and the dose assessment process, Monte Carlo simulations for internal dosimetry, uncertainties in internal dosimetry, and internal microdosimetry. Several intercomparison exercises and training courses have been organised. The IDEAS guidelines, which describe – based on the International Commission on Radiological Protection’s (ICRP) biokinetic models and dose coefficients – a structured approach to the assessment of internal doses from monitoring data, are maintained and updated by the group. In addition, Technical Recommendations for Monitoring Individuals for Occupational Intakes of Radionuclides have been elaborated on behalf of the European Commission, DG-ENER (TECHREC Project, 2014–2016, coordinated by EURADOS). Quality assurance of the ICRP biokinetic models by calculation of retention and excretion functions for different scenarios has been performed and feedback was provided to ICRP. An uncertainty study of the recent caesium biokinetic model quantified the overall uncertainties, and identified the sensitive parameters of the model. A report with guidance on the application of ICRP biokinetic models and dose coefficients is being drafted at present. These and other examples of the group’s activities, which complement the work of ICRP, are presented. © 2018, The International Society for Prosthetics and Orthotics.

In order to properly respond to an emergency of nuclear and radiological terrorism, we realized a mobile complex system (MCS) for conducting on field a large-scale individual monitoring of internal contamination by gamma emitters. The proposed MCS consists of a collective protection apparatus and a HPGe portable spectrometer for whole-body and thyroid measurements. The MCS performance was evaluated and showed, assuming, for instance, an acute inhalation of 137Cs and 131I occurred 5 days before measurement, detection limit values resulting in a committed effective dose equal to 0.07 mSv, and a maximum committed equivalent dose to thyroid equal to 1.3 mSv, respectively. Considering the annual limit of effective dose for public exposure and the lowest reference level to plan stable iodine prophylaxis, the proposed MCS has a significant sensitivity to be used for fast internal monitoring in nuclear and radiological emergencies from malicious acts. This MCS allows to operate in contaminated environment and to monitor daily a large amount of individuals.

The European Radiation Dosimetry Group, EURADOS, established a working group consisting of experts whose aim is to assist in the process of harmonisation of individual monitoring as part of the protection of occupationally exposed workers. A catalogue of facilities and internal dosimetric techniques related to individual monitoring in Europe has been completed as a result of this EURADOS study. A questionnaire was sent in 2002 to services requesting information on various topics including type of exposures, techniques used for direct and indirect measurements including calibration and sensitivity data and the methods employed for the assessment of internal doses. Information relating to Quality Control procedures for direct and indirect measurements, Quality Assurance Programmes in the facilities and legal requirements for "approved dosimetric services" were also considered. A total of 71 completed questionnaires were returned by internal dosimetry facilities in 26 countries. This results in an overview of the actual status of the processes used in internal exposure estimation in Europe. In many ways harmonisation is a reality in internal dose assessments, especially when taking into account the measurements of the activity retained or excreted from the body. However, a future study detailing the estimation of minimum detectable activity in the laboratories is highly recommended. Points to focus on in future harmonisation activities are as follows: the process of calculation of doses from measured activity, establishment of guidelines, similar dosimetric tools and application of the same ICRP recommendations. This would lead to a better and more harmonised approach to the estimation of internal exposures in all European facilities.

International audience; Dose assessment after intakes of radionuclides requires application of biokinetic and dosimetric models and assumptions about factors influencing the final result. In 2006, a document giving guidance for such assessment was published, commonly referred to as the IDEAS Guidelines. Following its publication, a working group within the European networks CONRAD and EURADOS was established to improve and update the IDEAS Guidelines. This work resulted in Version 2 of the IDEAS Guidelines, which was published in 2013 in the form of a EURADOS report. The general structure of the original document was maintained; however, new procedures were included, e.g. the direct dose assessment method for 3H or special procedure for wound cases applying the NCRP wound model. In addition, information was updated and expanded, e.g. data on dietary excretion of U, Th, Ra and Po for urine and faeces or typical and achievable values for detection limits for different bioassay measurement techniques. © The Author 2015. Published by Oxford University Press. All rights reserved.

International audience; The TECHREC project, funded by the European Commission, will provide Technical Recommendations for Monitoring Individuals for Occupational Intakes of Radionuclides. It is expected that the document will be published by the European Commission as a report in its Radiation Protection Series during 2016. The project is coordinated by the European Radiation Dosimetry Group (EURADOS) and is being carried out by members of EURADOS Working Group 7 (Internal Dosimetry). This paper describes the aims and purpose of the Technical Recommendations, and explains how the project is organised. © Crown copyright 2015.

EURADOS working group on 'Internal Dosimetry (WG7)' represents a frame to develop activities in the field of internal exposures as coordinated actions on quality assurance (QA), research and training. The main tasks to carry out are the update of the IDEAS Guidelines as a reference document for the internal dosimetry community, the implementation and QA of new ICRP biokinetic models, the assessment of uncertainties related to internal dosimetry models and their application, the development of physiology-based models for biokinetics of radionuclides, stable isotope studies, biokinetic modelling of diethylene triamine pentaacetic acid decorporation therapy and Monte-Carlo applications to in vivo assessment of intakes. The working group is entirely supported by EURADOS; links are established with institutions such as IAEA, US Transuranium and Uranium Registries (USA) and CEA (France) for joint collaboration actions. © The Author 2010. Published by Oxford University Press. All rights reserved.

The CONRAD Project is a Coordinated Network for Radiation Dosimetry funded by the European Commission 6th Framework Programme. The activities developed within CONRAD Work Package 5 ('Coordination of Research on Internal Dosimetry') have contributed to improve the harmonisation and reliability in the assessment of internal doses. The tasks carried out included a study of uncertainties and the refinement of the IDEAS Guidelines associated with the evaluation of doses after intakes of radionuclides. The implementation and quality assurance of new biokinetic models for dose assessment and the first attempt to develop a generic dosimetric model for DTPA therapy are important WP5 achievements. Applications of voxel phantoms and Monte Carlo simulations for the assessment of intakes from in vivo measurements were also considered. A Nuclear Emergency Monitoring Network (EUREMON) has been established for the interpretation of monitoring data after accidental or deliberate releases of radionuclides. Finally, WP5 group has worked on the update of the existing IDEAS bibliographic, internal contamination and case evaluation databases. A summary of CONRAD WP5 objectives and results is presented here.

The work of Task Group 5.1 (uncertainty studies and revision of IDEAS guidelines) and Task Group 5.5 (update of IDEAS databases) of the CONRAD project is described. Scattering factor (SF) values (i.e. measurement uncertainties) have been calculated for different radionuclides and types of monitoring data using real data contained in the IDEAS Internal Contamination Database. Based upon this work and other published values, default SF values are suggested. Uncertainty studies have been carried out using both a Bayesian approach as well as a frequentist (classical) approach. The IDEAS guidelines have been revised in areas relating to the evaluation of an effective AMAD, guidance is given on evaluating wound cases with the NCRP wound model and suggestions made on the number and type of measurements required for dose assessment.

The IDEAS Guidelines for the assessment of internal doses from monitoring data suggest default measurement uncertainties (i.e. scattering factors, SFs) to be used for different types of monitoring data. However, these default values were mainly based upon expert judgement. In this paper, SF values have been calculated for different radionuclides and types of monitoring data using real data contained in the IDEAS Internal Contamination Database. Results are presented. © The Author 2007. Published by Oxford University Press. All rights reserved.

The EUropean RAdiation DOSimetry Group (EURADOS) initiated in 2005 the CONRAD Project, a Coordinated Network for Radiation Dosimetry funded by the European Commission (EC), within the 6th Framework Programme (FP). The main purpose of CONRAD is to generate a European Network in the field of Radiation Dosimetry and to promote both research activities and dissemination of knowledge. The objective of CONRAD Work Package 5 (WP5) is the coordination of research on assessment and evaluation of internal exposures. Nineteen institutes from 14 countries participate in this action. Some of the activities to be developed are continuations of former European projects supported by the EC in the 5th FP (OMINEX and IDEAS). Other tasks are linked with ICRP activities, and there are new actions never considered before. A collaboration is established with CONRAD Work Package 4, dealing with Computational Dosimetry, to organise an intercomparison on Monte Carlo modelling for in vivo measurements of 241Am deposited in a knee phantom. Preliminary results associated with CONRAD WP5 tasks are presented here. © The Author 2007. Published by Oxford University Press. All rights reserved.

L’Istituto di Radioprotezione ENEA (IRP), che assicura la sorveglianza fisica di radioprotezione all’interno dei centri di ricerca ENEA, nell’ambito delle proprie attività ha istituito un gruppo di lavoro tra gli Esperti Qualificati dell’Agenzia che si occupasse della stesura di una serie di procedure a supporto delle attività istituzionali. All’interno di questo progetto è stato elaborato un documento che illustra la procedura operativa applicata in ambito IRP per la misura indiretta della contaminazione superficiale rimovibile ,  e , senza impiego di contatori a scintillazione liquida. Lo scopo delle misure di contaminazione superficiale con finalità di sorveglianza fisica è quello di controllare l’esposizione alle radiazioni stimando la concentrazione, il rilascio e la risospensione in aria di materiale radioattivo per valutare il conseguente impatto sui lavoratori e sulla popolazione attraverso esposizione esterna e/o interna. La contaminazione superficiale è generalmente costituita da una componente fissa e una rimovibile. La prima è intimamente integrata con i materiali della superficie mentre la seconda può essere rimossa con semplici operazioni di pulizia e strofinio e può molto facilmente essere rilasciata dal materiale. L’applicabilità e l’affidabilità delle misure dirette o delle valutazioni indirette della contaminazione superficiale dipendono dall’entità di queste due componenti, tanto che talvolta i metodi indiretti che si avvalgono del prelievo di un campione per la successiva misura sono indicati come procedura di elezione nella determinazione della contaminazione superficiale. La procedura sviluppata e qui descritta fornisce le indicazioni necessarie per valutare i livelli di contaminazione superficiale rimovibile tramite campagne di misura condotte con la tecnica conosciuta con il termine “smear test” o di strofinio, consigliando anche le metodiche più accreditate sulla base di diverse condizioni e in presenza di diverse situazioni operative. Nella medesima procedura si propone anche una strategia di controllo che comprende diversi livelli o vincoli derivati in corrispondenza dei quali attuare azioni adeguate ad affrontare le situazioni che possono essere previste in funzione dei risultati del monitoraggio effettuato. In via preliminare sono quindi definiti e discussi livelli derivati di registrazione, indagine e intervento, al di sopra dei quali si opera rispettivamente nei modi seguenti: a) si registra il livello di contaminazione rilevato nello specifico punto, b) si avvia un’indagine per stabilire le motivazioni che hanno portato al superamento dello specifico livello, c) si interviene con una decontaminazione dell’area interessata ed eventualmente con l’interdizione all’accesso in quell’area per un determinato periodo di tempo.

In recent major international intercomparison exercises on intake and internal dose assessments from monitoring data, the results calculated by different participants varied significantly. Based on this experience the need for harmonisation of the procedures has been formulated within an EU 5th Framework Programme research project. The aim of the project, IDEAS, is to develop general guidelines for standardising assessments of intakes and internal doses. The IDEAS project started in October 2001 and ended in June 2005. The project is closely related to some goals of the work of Committee 2 of the ICRP and since 2003 there has been close cooperation between the two groups. To ensure that the guidelines are applicable to a wide range of practical situations, the first step was to compile a database of well-documented cases of internal contamination. In parallel, an improved version of an existing software package was developed and distributed to the partners for further use. A large number of cases from the database was evaluated independently by the partners and the results reviewed. Based on these evaluations, guidelines were drafted and discussed with dosimetry professionals from around the world by means of a virtual workshop on the Internet early in 2004. The guidelines have been revised and refined on the basis of the experiences and discussions in this virtual workshop. The general philosophy of the Guidelines is presented here, focusing on the principles of harmonisation, optimisation and proportionality. Finally, the proposed Levels of Task to structure the approach of internal dose evaluation are reported.

Au cours des exercices recents d’intercomparaison, les estimations de dose interne et d’incorporation calculees par les differents participants a partir des donnees de surveillance ont montre une grande variabilite. Ceci est du principalement a la diversite des methodes et des hypotheses appliquees dans la procedure d’evaluation. A partir de ce constat, le besoin d’une harmonisation des procedures a ete formule a travers un projet de recherche europeen dans le cadre du 5e PCRD. Le but de ce projet, IDEAS, est de proposer un guide pratique pour homogeneiser les evaluations de dose interne et d’incorporation. Le projet IDEAS a debute en octobre 2001 et s’achevera en mai 2005. Huit institutions de sept pays europeens y participent. Il est aussi fait appel aux contributions de professionnels de la dosimetrie interne de toute l’Europe pour assurer un large consensus au resultat du projet. IDEAS s’interesse de pres a certains des objectifs du comite 2 de la CIPR et les deux groupes entretiennent une etroite collaboration depuis 2003. Afin de s’assurer que les conseils soient applicables a un large spectre de situations concretes, la premiere etape a ete la compilation d’une base de donnees bien documentee de cas de contamination interne. En parallele, une version amelioree d’un logiciel deja existant a ete developpee et distribuee aux partenaires pour une utilisation dans la suite du projet. Un grand nombre des cas de la base de donnees a ete evalue independamment par les partenaires du projet en utilisant le meme logiciel et les resultats ont ete analyses. Sur la base de ces evaluations, une premiere version du guide a ete editee et discutee avec les professionnels de la dosimetrie du monde entier par le biais d’un seminaire virtuel sur Internet en juin 2004. Les indications seront revisees et affinees a partir des discussions et experiences rapportees au cours de ce seminaire virtuel ainsi que du resultat de l’exercice d’intercomparaison qui sera organise dans le cadre du projet et ouvert a tous les professionnels de la dosimetrie interne.

In recent years a cooperation agreement has been established between Austrian, Italian and Hungarian institutions to check and improve performances of WBC laboratories operating in these countries. In this context the KFKI Atomic Energy Research Institute from Budapest, Hungary, and the ENEA Institute for Radiation Protection from Bologna, Italy, organised an intercomparison exercise in which altogether 15 WBC arrangements from 12 institutions of the two countries have been tested. For this purpose the KFKI prepared a modular type phantom enabling a simulation of different body sizes. For intercomparison 20, 50 and 70 kg body weights were used. 22 Na, 40 K, 57 Co and 137 Cs were selected as the radionuclides to be identified and then their activities determined. The majority of submitted results for all radionuclides and body sizes met the requirements of performance criteria internationally accepted for accuracy in terms of relative bias: however, few outlying results, indicating insufficiencies in calibration procedures, were also found.

An intercalibration campaign has been carried out in Italy aimed at evaluating and comparing the performances of NaI(T1), phoswich and HPGe based detector systems for measurement of transuranic elements ( 241 Am and 239 Pu) in lungs. For the calibration, a Livermore realistic chest phantom was used. On the basis of a proposed procedure for MDA evaluation, repeated time delayed measurements of definitely uncontaminated subjects, having different body masses, were performed for 'blank' count evaluation in order to assess both intra-subject and inter-subject count variability. Results of this intercalibration campaign are presented together with MDA values for all NaI(Tl), phoswich and HPGe detector based systems involved. The necessity of a common procedure to assess system performance in in vivo measurement of transuranic elements is discussed and the proposed methodology for evaluation of minimum detectable activity is also presented.

In the scope of the IDEAS project to develop General Guidelines for the Assessment of Internal Dose from Monitoring data, two databases were compiled. The IDEAS Bibliography database contains references dealing with problems related to cases of internal contamination. The IDEAS Internal Contamination Database now contains more than 200 cases of internal contamination. In the near future, the IDEAS Internal Contamination database will be made available to the internal dosimetry community. The database has several potential applications, including: training, testing biokinetic models, testing software for calculating intakes and doses from bioassay data, comparison of data from a new accidental intake with that from previous exposures to similar materials. The database is by no means complete, and this presentation is also an appeal for internal contamination cases to extend and update it.

Several international inter-comparison exercises on intake and internal dose assessments from monitoring data led to the conclusion that the results calculated by different participants varied significantly, mainly due to the broad variety of methods and assumptions applied in the assessment procedure. Based on these experiences, the need of harmonisation of the procedures has been formulated as an EU research project under the 5th Framework Programme, with the aim of developing general guidelines for standardising assessments of intakes and internal doses. In the IDEAS project, eight institutions from seven European countries are participating, also using inputs from interval dosimetry professionals from across Europe to ensure broad consensus in the outcome of the project. To ensure that the guidelines are applicable to a wide range of practical situations, the first step will be to compile a database on well documented cases of internal contamination. In parallel, an improved version of existing software will he developed and distributed to the partners for further use. Many cases from the database will be evaluated independently by more partners using the same software and the results will be discussed and the draft guidelines prepared. The guidelines will then be revised and refined on the basis of the experiences and discussions of two workshops, and an inter-comparison exercise organised in the frame of the project which will be open to all internal dosimetry professionals.

As part of the EU Fifth Framework Programme IDEAS project 'General Guidelines for the Evaluation of Incorporation Monitoring Data', and in collaboration with the International Atomic Energy Agency, a new intercomparison exercise for the assessment of doses from intakes of radionuclides was organised. Several cases were selected, to cover a wide range of practices in the nuclear fuel cycle and medical applications. The cases were: (1) acute intake of HTO, (2) acute inhalation of the fission products 137Cs and 90Sr, (3) acute inhalation of 60Co, (4) repeated intakes of 131I, (5) intake of enriched uranium and (6) single intake of Pu isotopes and 241Am. This intercomparison exercise especially focused on the effect of the Guidelines proposed by the IDEAS project for harmonisation of internal dosimetry. © The Author 2007. Published by Oxford University Press. All rights reserved.

The need for harmonisation of the procedures for internal dose assessment has been recognised within an EU research project under the 5th Framework Programme. The aim of the IDEAS project was to develop general guidelines for standardising assessments of intakes and internal doses. It started in October 2001 and ended in June 2005. The project is closely related to some goals of the work of Committee 2 of the International Commission on Radiological Protection and since 2003 there has been close co-operation between the two groups. The general philosophy of the guidelines is focusing on the principles of harmonisation, accuracy and proportionality. The proposed system of 'level of task' to structure the approach of internal dose evaluation is also reported. Some details of the internal structure of the guidelines for the different pathways of intake are provided. © The Author 2007. Published by Oxford University Press. All rights reserved.

An Internet based intercomparison exercise on assessment of occupational exposure due to intakes of radionuclides has been performed to check the applicability of the 'General Guidelines for the Assessment of Internal Dose from Monitoring Data' developed by the IDEAS group. There were six intake cases presented on the Internet and 81 participants worldwide reported solutions to these cases. Results of the exercise indicate that the guidelines have a positive influence on the methodologies applied for dose assessments and, if correctly applied, improve the harmonisation of assessed doses.

In radiation protection dosimetry the quantity of interest is the effective dose (E); the dose limit to an adult worker applies to the sum of the relevant doses from external exposures and the relevant committed effective doses from intakes of radionuclides, during the same period of time. A EURADOS study was carried out to investigate how the results from personal dosemeters for external radiation, from workplace monitoring and from monitoring of internal exposures can be combined into a consistent system of individual monitoring. The integration of dosimetric methods and data for external and internal radiation require the complete characterisation of the occupational exposure present at the workplace, and the availability of adequate equipment and tools for the assessment of effective dose. To evaluate the capability of services to accomplish this approach, a European Dosimetry Network has been established among 28 European countries through the respective contact-persons and their dosimetric facilities which collaborated with EURADOS providing relevant data about performance and legal aspects. The information collected was presented as a monograph in Radiation Protection Dosimetry in 2004. The more relevant conclusions of this study are presented here.

Once the EC Directive 96/29 has been implemented into national regulation across Europe, the coordination of dosimetry laboratories for the monitoring of occupational exposures becomes the principal aim to achieve. Within this framework the European Radiation Dosimetry Group, EURADOS, carried out an Action on 'Harmonisation of Individual Monitoring' (2000-2004) to promote coordination in the field of individual monitoring of occupational exposures throughout Europe. With reference to internal exposures, the main aims were the completion of a catalogue of internal dosimetry services and an inventory of methods and techniques used for individual monitoring at European internal dosimetry facilities. At the end of this EURADOS Action, a report was published in Radiation Protection Dosimetry in 2004. The information collected related to various topics: the equipments used for the measurement of internal exposures, calibration and sensitivity data, the methods applied for the assessment of internal doses, Quality Control procedures, Quality Assurance Programmes in the facilities and legal requirements. The information to be presented here will give a general overview of the actual status of individual monitoring for internal exposures in Europe.

Following the publication of the EU Council Directive 96/29, EURADOS coordinated two working groups (WGs) for promoting the process of harmonisation on individual monitoring of occupationally exposed persons in Europe. An overview of the major findings of the second WG is presented. Information on the technical and quality standards and on the accreditation and approval procedures has been compiled. The catalogue of dosimetric services has been updated and extended. An overview of national regulations and standards for protection from radon and other natural sources in workplaces has been made, attempting to combine the results from individual monitoring for external, internal and workplace monitoring. A first status description of the active personal dosemeters, including legislative and technical information, and their implementation has been made. The importance of practical factors on the uncertainty in the dose measurement has been estimated. Even if a big progress has been made towards harmonisation, there is still work to be done. © 2006 Oxford University Press.

The catalogue of dosemeters and dosimetric services within the European Union (EU) Member States and Switzerland that was issued by EURADOS in the year 2000 has been updated and extended with information on dosimetric services in the new EU Member States and Bulgaria, Croatia, Romania, Serbia and Montenegro, and Ukraine. The total number of dosimetric services in these European countries is now estimated to be about 200. The present catalogue is based on information collected from 90 European dosimetric services, among which 34 questionnaires from 32 services were obtained over the years 2001-2004 for the first time. This article assesses and updates the present use of personal dosemeters and the extent to which occupationally exposed persons in Europe are monitored with dosemeters able to measure the operational quantity-personal dose equivalent, H P (d). The perspective of joining EU by the new countries accelerated the implementation of the EU Basic Safety Standard Directive to their national regulations. As a result, all newly investigated services reported their ability to measure H P (d). The catalogue provides information on the dosemeters, dose calculation and background subtraction algorithms, calibration methods, energy and angular response, and performance.

Part of the action of the EURADOS working group (European Radiation Dosimetry Group) on "Harmonisation of Individual Monitoring in Europe" was to investigate how the results from personal dosemeters for external radiation, from monitoring for internal exposure and from workplace monitoring, can be combined into a complete and consistent system of individual monitoring. To facilitate this work, the "EURADOS questionnaire Q3" relating to radon and other natural sources of radiation in the workplace was distributed to relevant institutes across Europe. A total of 24 countries replied to the questionnaire. This study offers an important overview on actual regulations, national standards and reference levels for protection of employees from radon and other natural sources in different workplace scenarios. Information was also collected on individual monitoring and area monitoring to determine individual doses in workplaces with elevated levels of natural radiation. The article discusses in detail the results obtained showing by country the reference level in workplaces for radon gas and other natural sources. In both instances, exposures in mines, other underground workplaces, industry workplaces/waterworks, offices, schools and day-care homes were considered. The resultant data clearly indicate that there is a need for harmonisation among countries, not least in the areas of regulation and use of reference levels in the workplace.

When a set of bioassay data is given to two different dosimetrists, it is likely that these data will be interpreted differently, that different methods and dosimetric models will be applied and therefore different numerical values will be obtained. Thus, it is important for laboratories dealing with internal dosimetry to undergo performance testing procedures such as interlaboratory comparisons of bioassay data interpretation. Several intercomparison exercises have already been organised at national and international levels. The largest one so far was the 3rd European Intercomparison Exercise on Internal Dose Assessment, which has been organised in the framework of the EULEP/EURADOS Action Group, 'Derivation of parameter values for application to the new model of the human respiratory tract for occupational exposure'. The most important lesson learned from these intercomparison exercises was the need to develop agreed guidelines for internal dose evaluation procedures to promote harmonisation of assessments between organisations and countries.

A revised model of molybdenum biokinetics in humans was recently developed on the basis of experimental data gathered in specific investigations conducted with stable tracers. The model can be used for radiation protection purposes, and it is also a suitable working tool for designing new investigations aimed at further improvements to the model. For the latter goal, a sensitivity analysis was performed in order to determine the most significant model parameters in relation to output measurements performed in studies of molybdenum metabolism. A typical sensitivity analysis approach was adopted, considering the effects in variation of model parameters on the time courses of model outputs such as urinary excretion and blood clearance. A recent new sensitivity technique was considered too, based on the calculation of the so-called generalised sensitivity functions. This combines the sensitivities of the model output with respect to model parameters (as in the typical sensitivity analysis method), with the sensitivities of parameter estimates with respect to changes in model outputs. The results obtained in this analysis suggests that data collected in the first 7 h are critical for the definition of the process of blood clearance and related parameters, whereas reliable information at later times is required for a proper characterisation of urinary excretion.

In 2001, the Radiation Protection Institute of ENEA promoted an Italian intercomparison exercise on internal dose assessment addressed to the qualified experts in radiation protection, following the coming into force in Italian law of the EURATOM 96/29 Directive. Five case studies of occupational exposure related to the Italian situation are used. The considered radioisotopes are : 60Co, 89Sr, 125I, 131I, and 222Rn + NORM (238U-235U-232Th). Data related to WBC, thyroid and urine excretion measurements, as well as radionuclide air concentration in the workplace, are provided to the participants. The results related to medical, industrial and Rn occupational exposure are well represented as means of log-normal distributions with values of the geometric standard deviation less than 2. A wider spread of results is present for the evaluation of occupational exposure to NORM.