Biomedical subjects

C Hurtgen

Publications and source records attributed to C Hurtgen.

10 recordsLinked to original sources

PubMed2006

General guidelines for the assessment of internal dose from monitoring data: progress of the IDEAS project.

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.

Algorithms↗

PubMed2006

IDEAS internal contamination database: a compilation of published internal contamination cases. A tool for the internal dosimetry community.

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.

Biological Assay↗

PubMed2003

OMINEX: survey of internal dose monitoring programmes for radiation workers.

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.

Data Collection↗

PubMed2003

A survey on uncertainty in bioassay measurements carried out within the OMINEX project.

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.

Alpha Particles↗

PubMed2003

Lessons learned from interlaboratory comparisons of bioassay data interpretation.

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.

Benchmarking↗

PubMed2003

Design and implementation of monitoring programmes for internal exposure (project OMINEX).

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.

Body Burden↗

PubMed2003

Guidance on internal dose assessments from monitoring data (project IDEAS).

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.

Body Burden↗

PubMed2000

A multiple window deconvolution technique for measuring low-energy beta activity in samples contaminated with high-energy beta impurities using liquid scintillation spectrometry

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.

Journal Article↗

PubMed2000

Revisiting Currie--how low can you go?

Over the years many different formulae have been proposed to derive the 'limits of detection' for radiometric measurements. With the ever increasing employment of quality systems within the radioanalytical laboratory, it is vital that the term 'limit of detection' is well understood and defined in the documentation in use within the laboratory. This paper reviews the various formulae used to derive a limit of detection, most of which claim to be derived from Currie's landmark paper of 1968, which set out in detail the means by which the analyst can arrive at a limit of detection and limit of determination. However, with the vastly increased computing power available to the analyst, coupled with the off-the-shelf availability of low and zero background detectors, it is now more straightforward to arrive at exact solutions to define limits of detection and determination. Finally, we set out some examples of decision making at these limits and how this may inform the way in which detector time is allocated for the measurement of samples containing low levels of radioactivity.

Journal Article↗

PubMedDate not supplied

The measurement of technetium-99 and iodine-129 in waste water from pressurized nuclear-power reactors.

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.

Belgium↗