RESUMO
Sample load capacity, sample compatibility, influence of sample load on (3)H/(14)C counting efficiency, background count rate, figure of merit, quench resistance, and sample stability for nine selected, commercially available, liquid scintillation cocktails are presented in this study. The cocktails tested are Ecoscint A, Insta-Gel Plus, OptiPhase Hisafe 3, OptiPhase Trisafe, Ready Gel, SafeScint 1:1, Ultima Gold, Ultima Gold LLT, and Ultima Gold XR. For the data acquisition a Packard TriCarb Model 1900CA and a Quantulus 1220 liquid scintillation counter is used. All samples are prepared in either 20mL low potassium, borosilicate glass vials or 20mL high density, polyethylene vials. The aim of the full comparison study is to determine a single cocktail that best suits all measurement requirements of the liquid scintillation laboratory at SCK.CEN for the determination of low levels of radioactivity in biological and environmental samples. The results published in this report are intended to help other laboratories in selecting a cocktail fit for their purposes or to set up a similar study.
RESUMO
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.
Assuntos
Bases de Dados como Assunto , Monitoramento de Radiação , Radioisótopos/administração & dosagem , Teorema de Bayes , Creatinina/efeitos da radiação , Creatinina/urina , Fezes/química , Guias como Assunto , Humanos , Modelos Biológicos , Lesões por Radiação/fisiopatologia , Radioisótopos/química , Espalhamento de Radiação , Gravidade Específica/efeitos da radiação , Trítio/efeitos da radiação , Trítio/urina , Incerteza , Urina/químicaRESUMO
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.
Assuntos
Doses de Radiação , Monitoramento de Radiação , Radiometria , Dosagem Radioterapêutica , Pesquisa , Simulação por Computador , Bases de Dados como Assunto , Humanos , Modelos Teóricos , Método de Monte Carlo , Imagens de Fantasmas , Garantia da Qualidade dos Cuidados de Saúde , Radioisótopos/administração & dosagem , Radiometria/instrumentação , IncertezaRESUMO
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.
Assuntos
Carga Corporal (Radioterapia) , Internet , Exposição Ocupacional/análise , Monitoramento de Radiação/normas , Proteção Radiológica/normas , Medição de Risco/normas , Europa (Continente) , Humanos , Internacionalidade , Exposição Ocupacional/prevenção & controle , Controle de Qualidade , Eficiência Biológica Relativa , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
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.
Assuntos
Bioensaio/métodos , Bases de Dados Factuais , Exposição Ambiental/análise , Modelos Biológicos , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Radioisótopos/farmacocinética , Simulação por Computador , Humanos , Internacionalidade , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
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.
Assuntos
Fidelidade a Diretrizes/normas , Guias como Assunto , Modelos Biológicos , Exposição Ocupacional/análise , Monitoramento de Radiação/normas , Proteção Radiológica/normas , Gestão da Segurança/normas , Algoritmos , Simulação por Computador , Europa (Continente) , Humanos , Exposição Ocupacional/prevenção & controle , Padrões de Referência , Eficiência Biológica Relativa , Medição de Risco/normasRESUMO
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.
Assuntos
Algoritmos , Bioensaio/métodos , Modelos Biológicos , Guias de Prática Clínica como Assunto , Radiometria/métodos , Simulação por Computador , União Europeia , Humanos , Doses de Radiação , Eficiência Biológica RelativaRESUMO
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.
Assuntos
Bioensaio/métodos , Guias de Prática Clínica como Assunto , Radiometria/métodos , Carga Corporal (Radioterapia) , Europa (Continente) , Fidelidade a Diretrizes , Doses de Radiação , Sensibilidade e EspecificidadeRESUMO
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.
Assuntos
Bioensaio/estatística & dados numéricos , Bioensaio/normas , Fidelidade a Diretrizes/estatística & dados numéricos , Fidelidade a Diretrizes/normas , Guias de Prática Clínica como Assunto , Radiometria/estatística & dados numéricos , Radiometria/normas , Carga Corporal (Radioterapia) , União Europeia , Humanos , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
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 (241)Am deposited in a knee phantom. Preliminary results associated with CONRAD WP5 tasks are presented here.
Assuntos
Academias e Institutos/organização & administração , Bioensaio/métodos , União Europeia/organização & administração , Radiometria/tendências , Pesquisa/organização & administração , Carga Corporal (Radioterapia) , HumanosRESUMO
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 (3)H 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.
Assuntos
Exposição Ocupacional/análise , Exposição Ocupacional/normas , Doses de Radiação , Lesões por Radiação/prevenção & controle , Monitoramento de Radiação/métodos , Proteção Radiológica/normas , Bioensaio , Europa (Continente) , Fezes , Alemanha , Guias como Assunto , Humanos , Polônio/análise , Radioisótopos/análise , Rádio (Elemento)/análise , Medição de Risco , Tório/análise , Trítio , Urânio/análise , Urinálise , ÁguaRESUMO
One of the topics covered by the OMINEX (Optimisation of Monitoring for Internal Exposure) project was to look at the bioassay measurements performed in the European laboratories. Questionnaires on bioassay measurements by alpha spectrometry or inductively coupled plasma-mass spectrometry (ICP-MS) were sent to European laboratories. The main objective was to collect information on analytical procedures and on the uncertainties associated with bioassay results. Alpha spectrometry is the technique most often used for the determination of alpha emitters, such as actinides in biological samples. ICP-MS is not used much as yet for routine measurements of actinides in biological samples, but is very sensitive for measurements of long-lived radionuclides. The different parameters influencing the uncertainties on the results and the minimum detectable amount have been investigated. Optimum conditions for achieving low result uncertainties and high sensitivity are given for alpha spectrometry and ICP-MS.
Assuntos
Partículas alfa , Fezes/química , Espectrometria de Massas/métodos , Radioisótopos/análise , Radiometria/métodos , Radiometria/estatística & dados numéricos , Urinálise/métodos , Coleta de Dados , União Europeia , Espectrometria de Massas/estatística & dados numéricos , Doses de Radiação , Reprodutibilidade dos Testes , Tamanho da Amostra , Sensibilidade e Especificidade , Urinálise/estatística & dados numéricosRESUMO
Monitoring of the workforce in the nuclear industries is carried out primarily in order to demonstrate compliance with European Union (EU) legislation and the Basic Safety Standards for the protection of the health of workers against the dangers arising from ionizing radiation recommended by the International Atomic Energy Agency (IAEA). There is, however, no common strategy for internal dose monitoring programmes currently in use in the EU countries. Surveys have been carried out in which organisations were asked to provide information on the design of their internal dose monitoring programmes and on the costs of these programmes. Information was requested from both EU countries and Associated States. Databases for storage and reporting of all gained information were constructed, and results from the surveys have been compiled. This work was carried out within the EC 5th Framework Programme project, OMINEX, which aims to provide advice and guidance on designing and implementing internal dose monitoring programmes in the workplace in such a way that best use is made of available resources, while minimising costs.
Assuntos
Exposição Ocupacional/estatística & dados numéricos , Proteção Radiológica/métodos , Proteção Radiológica/estatística & dados numéricos , Radioisótopos/análise , Radiometria/métodos , Radiometria/estatística & dados numéricos , Coleta de Dados , Bases de Dados Factuais , União Europeia , Humanos , Exposição Ocupacional/análise , Doses de Radiação , Proteção Radiológica/normasRESUMO
The costs of monitoring for internal exposure in the workplace are usually significantly greater than the equivalent costs for external exposure. Therefore, there is a need to ensure that resources are employed with maximum effectiveness. The EC-funded OMINEX (optimisation of monitoring for internal exposure) project is developing methods for optimising the design and implementation of internal exposure monitoring programmes. Current monitoring programmes are being critically reviewed, the major sources of uncertainty in assessed internal dose investigated, and guidance formulated on factors such as programme design, choice of method/techniques, monitoring intervals, and monitoring frequency. OMINEX will promote a common, harmonised approach to the design and implementation of internal dose monitoring programmes throughout the EU.
Assuntos
Exposição Ocupacional/análise , Radiometria/métodos , Projetos de Pesquisa , Sociedades Científicas/organização & administração , Carga Corporal (Radioterapia) , Monitoramento Ambiental/métodos , Monitoramento Ambiental/normas , União Europeia , Humanos , Cooperação Internacional , Organizações , Doses de Radiação , Radiometria/normasRESUMO
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.
Assuntos
Benchmarking/métodos , Modelos Biológicos , Proteção Radiológica/normas , Radioisótopos/análise , Radioisótopos/farmacocinética , Radiometria/métodos , Radiometria/estatística & dados numéricos , Simulação por Computador , Comportamento Cooperativo , Europa (Continente) , Humanos , Relações Interinstitucionais , Variações Dependentes do Observador , Exposição Ocupacional/análise , Doses de Radiação , Proteção Radiológica/métodos , Proteção Radiológica/estatística & dados numéricos , Poluentes Radioativos/análise , Radiometria/normas , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
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 internal 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 be 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 intercomparison exercise organised in the frame of the project which will be open to all internal dosimetry professionals.
Assuntos
Bases de Dados Factuais/normas , Guias como Assunto , Exposição Ocupacional/análise , Radiometria/métodos , Radiometria/normas , Projetos de Pesquisa , Sociedades Científicas/organização & administração , Carga Corporal (Radioterapia) , Monitoramento Ambiental/métodos , Monitoramento Ambiental/normas , União Europeia , Humanos , Cooperação Internacional , Organizações , Doses de RadiaçãoRESUMO
Abstract models have been developed to describe dissolution of Pu/Am/Cm after internal contamination by inhalation or wound, chelation of actinides by diethylene triamine penta acetic acid (DTPA) in different retention compartments and excretion of actinide-DTPA complexes. After coupling these models with those currently used for dose calculation, the modelling approach was assessed by fitting human data available in IDEAS database. Good fits were obtained for most studied cases, but further experimental studies are needed to validate some modelling hypotheses as well as the range of parameter values. From these first results, radioprotection tools are being developed: MAnagement of DOse Reduction after DTPA therapy.
Assuntos
Ácido Pentético/uso terapêutico , Proteção Radiológica/métodos , Elementos da Série Actinoide/análise , Algoritmos , Bile , Quelantes/química , Simulação por Computador , Fezes , Humanos , Fígado/metabolismo , Modelos Biológicos , Modelos Teóricos , Lesões por Radiação/tratamento farmacológico , Protetores contra Radiação/administração & dosagem , UrinaRESUMO
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.
Assuntos
Radiometria/normas , Amerício/análise , Europa (Continente) , Humanos , Cinética , Método de Monte Carlo , Ácido Pentético/química , Plutônio/análise , Controle de Qualidade , Monitoramento de Radiação/métodos , Radioisótopos/análise , Radiometria/métodos , Valores de Referência , Sistema de Registros , Reprodutibilidade dos Testes , Urânio/análiseRESUMO
The program for measuring the dispersal presence of contaminating nuclides in waste streams produced by pressurized-water-reactor (PWR) power plants required the establishment of analytical procedures for a number of nuclides. In this report the procedure to assess 99Tc and 129I content in liquid samples using liquid-scintillation counting is presented. 99Tc and 129I are adsorbed on AG 1 X2 ion-exchange resin. 129I is then eluted with NaOCl and further purified by liquid-liquid extraction using carbon tetrachloride and an aqueous solution of sodium thiosulphate. 99Tc is eluted with hot nitric acid (6 M/60 degrees C). If necessary any 60Co present in the sample is separated by liquid-liquid extraction of the cobalt-TTA complex with iso-BuOH. The overall recovery yield is 96.5 +/- 2.5% for 99Tc and 90.1 +/- 6.2% for 129I. Finally beta-activity is measured by liquid-scintillation counting. A limit of detection of 5 Bq/L can thus be obtained for both 99Tc and 129I.
Assuntos
Radioisótopos do Iodo/análise , Reatores Nucleares , Resíduos Radioativos/análise , Tecnécio/análise , Bélgica , Eliminação de Resíduos LíquidosRESUMO
An optimised multiple window counting technique, using liquid scintillation counting combined with internal standardisation and spectrum unfolding has been developed for the assessment of low-level, low-energy beta activity in multilabeled samples containing high-energy beta impurities. Distinct spectral contributions are reconstructed for every individual radionuclide and impurity using software deconvolution techniques. The most important advantages of this method are that it does not require setting up quench correction curves and that the exact knowledge of reference activity is not required, thus eliminating two important sources of uncertainty in the final results. The technique has been successfully used on mixtures of 3H, 14C, 63Ni, 99Tc and 60Co over a wide range of quenching and activity ratios.