Radiation Protection Dosimetry (2011), Vol. 144, No. 1 4, pp. 124 129 Advance Access publication 30 November 2010 doi:10.1093/rpd/ncq412 ACCREDITATION AND TRAINING ON INTERNAL DOSIMETRY IN A LABORATORY NETWORK IN BRAZIL: AN INCREASING DEMAND B. M. Dantas 1, *, A. L. A. Dantas 1, M. E. D. Acar 1, J. C. S. Cardoso 2, L. M. Q. C. Julião 1, M. F. Lima 2, M. H. T. Taddei 3, D. R. Arine 4, T. Alonso 5, M. A. P. Ramos 6 and A. Fajgelj 7 1 Instituto de Radioproteção e Dosimetria, IRD-CNEN, Av. Salvador Allende s/n, Rio de Janeiro, Brazil 2 Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN, São Paulo, Brazil 3 Laboratório de Poços de Caldas, LAPOC-CNEN, Poços de Caldas, Brazil 4 Laboratório Radioecológic, LARE-CTMSP, São Paulo, Brazil 5 Centro de Desenv. Tecn.Nuclear, CDTN-CNEN, Belo Horizonte, Brazil 6 Eletronuclear, CNAAA, Angra dos Reis, Brazil 7 Internation Atomic Energy Agency, Vienna, Austria *Corresponding author: bmdantas@ird.gov.br In recent years, Brazilian Nuclear Programme has been reviewed and updated by government authorities in face of the demand for energy supply and its associated environmental constraints. The immediate impact of new national programmes and projects in nuclear field is the increase in the number of exposed personnel and the consequent need for reliable dosimetry services in the country. Several Technical Documents related to internal dosimetry have been released by the International Atomic Energy Agency and International Commission on Radiological Protection. However, standard bioassay procedures and methodologies for bioassay data interpretation are still under discussion and, in some cases, both in routine and emergency internal monitoring, procedures can vary from one laboratory to another and responses may differ markedly among Dosimetry Laboratories. Thus, it may be difficult to interpret and use bioassay data generated from different laboratories of a network. The main goal of this work is to implement a National Network of Laboratories aimed to provide reliable internal monitoring services in Brazil. The establishment of harmonised in vivo and in vitro radioanalytical techniques, dose assessment methods and the implementation of the ISO/IEC 17025 requirements will result in the recognition of technical competence of the network. INTRODUCTION Besides worldwide recent application of financial resources in nuclear field, in Brazil such perspective is motivated by the federal government plans to expand Brazilian Nuclear Programme, including the construction of the third Nuclear Power Plant, in Angra dos Reis, located at the State of Rio de Janeiro as well as other four reactors, two in Northeast and two in Southeast Regions (1). Environmental aspects, markedly the fight against global warming and the need for a stable energy supply required by an economic progress in a constant basis turn nuclear energy into an important component of the energy matrix of the country. The production of radioisotopes and its application in medicine and biomedical research have grown intensely in recent years. According to the database available in the Brazilian Regulatory Board Database (2), there are 320 nuclear medicine centres in operation. The Southeast region accounts for about 70 % of the facilities, followed by the South with 13 % and the Northeast with about 10 %. The other facilities are distributed in Northern and Central-western regions. Individual monitoring is an essential practice for those who work in nuclear activities (3, 4). The assessment of internal exposure must be applied not only to routine occupational monitoring but also in accident situations, where there is a significant risk of occurrence of internal contamination. In Brazil, need for establishing routine assessment of internal exposure in nuclear medicine and research is still under discussion and depends on the implementation of the new version of the CNEN (Brazilian Nuclear Energy Commission) Basic Regulations on Radiological Protection. Intakes of radioactive materials are often assessed routinely for workers employed in areas that are designated as controlled (specifically in relation to the control of contamination) or in which there are grounds for expecting significant intakes (4, 5). One critical problem is to guarantee the reliability of the monitoring data provided by the laboratories in charge of such tasks. However, there are difficulties in comparing data on doses due to intakes of radionuclides in various countries because of different approaches in the selection of the monitoring programmes and in the interpretation of the monitoring data. # The Author 2010. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com
ACCREDITATION AND TRAINING ON INTERNAL DOSIMETRY Procedures can vary from one laboratory to other, introducing lack of confidence in the information provided to radiation protection officers, to the own worker and to competent authorities. Standard procedures for laboratories related to dosimetry and analytical methods are now freely available through the IAEA (International Atomic Energy Agency) (6 8). Several international intercomparison exercises for internal dose assessment have been organised (9 13). The most important lesson from these intercomparison exercises was the need to develop guidelines for internal dose evaluation procedures in order to promote harmonisation of assessments between organisations and countries. In the Third European Intercomparison Exercise on Internal Dose Assessment, organised in the framework of the EULEP/EURADOS Action Group (9), significant differences were revealed among laboratories in terms of their approaches, methods and assumptions, and consequently in their results. One major source of divergence at the time of the exercise was due to particular International Commission on Radiological Protection (ICRP) models used. Most dosimetry services were operating using models from ICRP Publications 26 (14) and 30 (15) for legal reasons. However, most were in the process of moving to new generation of ICRP models as Publications 66, 78 and 100) (16 18), partly because these are considered to be more realistic and partly because of the imminent implementation of the International Basic Safety Standards (19) and new EURATOM directive. Similar projects aiming to harmonise internal dosimetry procedures have been carried out in different parts of the world under the auspices of the IAEA (20). Administrative routines and laboratory procedures related to implementation and maintenance of quality assurance are stated by internationally accepted requirements established by the ISO/IEC 17025 (21). Implementation of ISO/IEC 17025 requirements is the unique condition to obtain accreditation since it is the basis for the recognition of technical competence of any calibration or assay laboratory, which is the case of the Brazilian internal dosimetry laboratory network. This work describes the implementation of a National Network of Laboratories aimed to perform radiological internal monitoring measurements in Brazil. The establishment of standardised radioanalytical techniques and dose assessment procedures among the network and the implementation of the ISO/IEC 17025 requirements will result in reliable dose assessment and in the recognition of technical competence of the laboratories. It is expected that the main beneficiaries of this network will be: workers that manipulate unsealed sources of radionuclides in several nuclear applications such as industry, medicine and research; members of the general public in the case of accidental releases of radioactive materials; national regulatory authorities and stakeholders in the nuclear area; and internal dosimetry services. The proposed network should implement good metrological practices and obtain recognition of internal dosimetry services provided in the country. This should be acquainted by human resources training programmes in international reference centres. Immediate goals of the network are the harmonisation of measurement techniques and dose assessment methodologies among national laboratories through the application of technical guides. Finally, individual laboratories should apply for accreditation to national and international quality assurance agencies. MATERIALS AND METHODS Currently available internal dosimetry services in Brazil consist of nine laboratories installed in governmental institutions under administration of three Ministries: Science and Technology; Navy; Mines and Energy. Seven laboratories are located in five research centres linked to the CNEN (Brazilian Nuclear Energy Commission): Institute for Radiation Protection and Dosimetry (IRD), Rio de Janeiro, RJ; Institute for Nuclear and Energetic Research (IPEN), São Paulo, SP; Poços de Caldas (LAPOC), Poços de Caldas, MG; Nuclear Technology Development Center (CDTN), Belo Horizonte, MG, and Regional Center for Nuclear Sciences (CRCN), Recife, PE (under implementation). The other two laboratories of the network are located at the Navy Technology Center (CTMSP), Iperó, SP and at the Nuclear Power Plant (CNAAA), Angra dos Reis, RJ. The nine laboratories included in the network can be divided into two groups depending of the bioassay technique they apply to estimate intake of radionuclides in human body, i.e., in vivo or in vitro laboratories. Figure 1 presents a scheme of the Brazilian administrative structure in which the laboratory network is implemented, and Figure 2 shows the distribution of the Laboratories within the Country. Table 1 summarises selected basic information on the infrastructure in terms of available techniques and sensitivities. Intercomparison exercises on in vivo and in vitro radioanalytical techniques and internal dose assessment will be scheduled in the process of implementing the network, in order to demonstrate their competence and verify conformity with the established requirements. The network has requested financial support from IAEA through a National Project in order to access other laboratories that have already implemented 125
B. M. DANTAS ET AL. Figure 1. Administrative structure of the Brazilian Network. Figure 2. Distribution of the Internal Dosimetry Network in Brazil. 126
ACCREDITATION AND TRAINING ON INTERNAL DOSIMETRY Table 1. Current status of internal dosimetry laboratories in Brazil. Facilities Detection systems MDA a IRD Whole-body Shielded room, one open room, one mobile system, one portable system Three NaI (Tl) 84, three NaI(Tl) 33, four HPGe 137 Cs (whole body) ¼ 88 Bq 60 Co (whole body) ¼ 86 Bq 131 I (thyroid) ¼ 23 Bq 123 I (thyroid) ¼ 3.5 Bq 18 F (whole body) ¼ 32 Bq 18 F (brain) ¼ 7.5 Bq 238 U (lungs) ¼ 46 Bq 235 U (lungs) ¼ 6.5 Bq 241 Am (lungs) ¼ 7Bq 210 Pb (skull) ¼ 16 Bq 210 Pb (knee) ¼ 5Bq IPEN Whole-body IRD Bioassay IPEN Radiotoxicology LAPOC Radiochemistry CTMSP Radioecology CDTN Whole-body CNAAA Whole-body CRCN Whole-body One shielded room One NaI (Tl) 8 00 4 00 99m Tc (whole body) ¼ 70 Bq One NaI (Tl) 3 00 3 00 123 I (thyroid) ¼ 40 Bq 131 I (thyroid) ¼ 10 Bq Two Radiochemistry Laboratories, two Instrumentation Laboratories One Radiochemistry One Radiochemistry One Radiochemistry One Shadow Shield Whole-body One Fast Scan Whole-body One HPGe, one NaI (Tl) 33, four surface barrier, one alpha beta system, one liquid scintillation Four digital fluorometer, one alpha spectrometer, one liquid scintillation, one gamma spectrometer Three gamma spectrometers, one ICP-OES, one alpha spectrometer with eight surface barrier detectors, one liquid scintillation, one ultra low level alpha beta One Gamma and alpha spectrometry system, one total alpha, beta and gamma system, one fluorometer, one liquid scintillation One NaI (Tl) 6 00 4 00 One NaI(Tl) 3 00 5 00 16 00 Unat (urine) ¼ 0.01 mg l 21 Thnat (urine) ¼ 0.02 mg l 21 238 U (urine) ¼ 1 mbq G 21 234 U(urine) ¼ 1.4 mbq g 21 235 U(urine) ¼ 1.4 mbq g 21 232 Th(urine) ¼ 1 mbq g 21 226 Ra (urine) ¼ 3 mbq l 21 226 Ra (feces) ¼ 3 mbq g 21 210 Pb (urine) ¼ 4 mbq l 21 210 Pb (feces) ¼ 4 mbq g 21 210 Po (urine) ¼ 4 mbq l 21 Unat (urine) ¼ 1 mg l 21 234 U (urine) ¼ 3 mbq l 21 238 U (urine) ¼ 5 mbq l 21 232 Th (urine) ¼ 1 mbq l 21 3 H (urine) ¼ 5Bql 21 234 U, 232 Th, 238 Pu, 239 Pu, 240 Pu, 241 Am Det. Limit ¼ 0.04 mbq l 21 3 H (urine) ¼ 1.7 Bq l 21 14 C (urine) ¼ 0.1 Bq l 21 90 Sr (urine) ¼ 4Bql 21 137 Cs, 134 Cs, 60 Co, 113 Sn, 133 Ba, 152 Eu, 54 Mn Det. Limit ¼ 1Bql 21 Unat (urine) ¼ 1 mg l 21 18 F (thorax) ¼ 8.6 Bq 60 Co (whole body) ¼ 150 Bq One Thyroid Probe One NaI(Tl) 2 00 2 00 131 I (thyroid) ¼ 246 Bq a MDA=minimum detectable activity. good practices and procedures. Official support from IAEA will allow the interchange of knowledge provided by fellowships, scientific visits and participation of foreign experts in training courses, as well 127 as acquisition of imported standards and equipment. IAEA support is also important to facilitate intercomparison of results with laboratories located in developed countries.
B. M. DANTAS ET AL. RESULTS During the year 2009, planed activities aimed to training personnel from network laboratories have been FUNDING This work was funded by the International Atomic Energy Agency (IAEA) and the Comissão Nacional fully accomplished, i.e. two courses on Internal de Energia Nuclear (CNEN-Brazil). Dosimetry of Radionuclides in Human Body, with a total of 30 participants; and one course on Metrology and Quality Management System in Analytical Laboratories in which 22 professionals were trained. These courses were offered in three locations in Brazil: IRD (Rio de Janeiro, RJ), CDTN (Belo REFERENCES 1. FONTE NUCLEAR Ano 15, No.06, fev. 2010. http:// www.aben.com.br. 2. Entidades Cadastradas Medicina Nuclear. http:// Horizonte, MG) and IPEN (São Paulo, SP). www.cnen.gov.br. For the years 2010 and 2011, the budget approved 3. International Atomic Energy Agency (IAEA). Occupational radiation protection. 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