Results of IAEA intercomparisons in the frame of indirect methods for assessing intakes of radionuclides

The IAEA safety activities to support the assessment of occupational exposure due to intake of radionuclides through a comprehensive set of Safety Guides, Safety Reports and other documents will soon be completed. The future IAEA activities in this field will focus more on training and international intercomparisons. In recent years extensive development in measurement techniques, phantoms and computational tools have occurred. Determination of the radionuclide activity in the body or excreta, the intake and the resulting internal dose can, therefore, be approached in many different ways, depending on the amount and quality of the data, the skill of the dosimetrist, computational tools available, the assumptions made and the methodology used. Thus, it is important for laboratories involved in internal dosimetry to undergo performance-testing procedures to demonstrate the correctness of the methods applied and also the consistency of their results with those obtained by other laboratories. Several intercomparison exercises were organized by the IAEA on the determination of radionuclides in human urine samples. These previous intercomparison exercises revealed significant differences in the approaches, methods and assumptions, and consequently in the results. This underlined the importance of this kind of intercomparison programmes as a key element of the harmonization process. The purpose of this paper is to present the current and future IAEA activities in support of assessment of occupational exposure due to intakes of radionuclides by organizing intercomparison runs focused on indirect methods for assessing intakes as well as the recommendations for setting up a Quality Management Systems for technical services in radiation safety.