Norwegian Radiation Protection Authority Research Articles

Lack of radioprotection knowledge and compliance in Norwegian equine ambulatory practice.

There is an increasing use of mobile radiographic units in equine ambulatory practices in Norway. Horse owners or handlers often participate in the radiographic examination in a non-controlled area. The aim of this descriptive, cross-sectional, survey study was to evaluate the radiation safety and protection in use of mobile radiography, and to identify areas where special attention from the regulatory authorities as well as veterinary educators would be required. A questionnaire was distributed to all equine veterinarians assumed to have access to mobile radiographic units, as part of a formal inspection in cooperation with the Norwegian Radiation Protection Authority. Few practices met the regulatory requirements of notifying the authorities of their radiographic units and designation of a radiation protection officer. The minority of the practices performed periodic quality assurance of their equipment. Many of the practices performed all of their radiographic examinations off-site. The examinations were most often performed in the aisle outside the horses' stalls, and few practices established an operating zone. The horse owner or handler participated in the radiographic examination in almost all of the practices. Few practices used dosimeters for determination of the radiation exposure. The study shows that there are major deficits in regulatory compliance in ambulatory equine radiography practices in Norway. The study also suggests that less stringent regulations and supervision may translate into less stringent radioprotection practices.

ICRP Fukushima dialogue seminars: joint learning at many levels.

The Norwegian Radiation Protection Authority and representatives from the CERAD Centre of Excellence participated at the majority of the International Commission on Radiological Protection dialogue seminars in Fukushima between 2011 and 2015. The open and sharing structure of the seminars contributed to an unprecedented understanding of the challenges faced by the general public affected by radioactive contamination due to an accident at a nuclear power plant. Most importantly by presentations from people in Fukushima, but also by presentations from lay people in Norway and Belarus who shared their experiences from the Chernobyl accident at several seminars. The seminars created new friendships and connections, which inter alia led to several exchange visits between affected people in Norway and Japan where worries and experiences could be shared in an open and reflective manner. The mix of actors (various experts, authorities, local populations) created joint learning across sectors and levels, representing an invaluable source of knowledge for organisations involved in nuclear and radiological emergency preparedness and planning.

NORWEGIAN-RUSSIAN COOPERATION IN NUCLEAR LEGACY REGULATION: CONTINUING EXPERIENCE AND LESSONS.

Safe management of nuclear legacies arising from past activities is a critical issue in maintaining confidence for the continuing and future use of radioactive materials. Effective and efficient regulatory supervision of nuclear legacy management is a critical part of that process. The Norwegian Radiation Protection Authority plays an active role in bilateral regulatory cooperation projects with sister authorities in the Russian Federation, as part of Norway's Plan of Action to improve radiation and nuclear safety. Based on this experience and by reference to specific legacy sites and facilities, this study provides an overview of the substantial progress made in remediation at the Site of Temporary Storage for spent fuel and radioactive waste at Andreeva Bay and presents radiation protection issues arising from the experience and lessons learned in this work. It is suggested that this experience can be useful in the further development of international recommendations, standards and guidance on remediation of nuclear legacies.

Belarus’ experience in post-Chernobyl communication with the local population, and some lessons learnt from involvement in the NERIS-TP project

This article presents the experience of post-Chernobyl management in Belarus associated with information interaction with the residents of the affected areas. It shows the evolution of the communication system throughout the whole period after the Chernobyl disaster, from communicating mostly with decision-making authorities in the first post-Chernobyl years to gradually shifting the major focus onto the public with the objective of promoting proactive attitudes towards restoration and development of the affected areas and improving the radiological culture of the affected residents. It also gives some important conclusions on the RIR’s participation in the NERIS-TP project as a subcontractor to the Norwegian Radiation Protection Authority (NRPA). Despite the long-term experience of Belarus in post-accident management and the important results achieved by implementing various measures in the post-accident recovery period, there is presently a great necessity to pay due attention to the emergency preparedness for a potential new accident, in particular in view of the construction of the first NPP in Belarus.

Inspection of cardiology departments in Norway: are they making it great in radiation protection?

Staff involved in interventional cardiology receive the highest occupational doses in Norway, and skin burns of patients have been reported. To identify the level of radiation protection (RP) for patients and staff, and compliance with the RP regulation, the Norwegian Radiation Protection Authority carried out inspections. The inspections were conducted (2013-14) as quality system reviews, based on document reviews, interviews, on-site inspections and observations of interventional procedures. The inspections revealed that most of the hospitals had non-compliances according to the RP regulation. Most deviations were associated with education in RP and follow-up of patients who had received high radiation doses. Lack of systematic optimisation of procedures and estimation of eye lens doses to evaluate the risk for cataracts were also common. Inspections turned out to increase the awareness of RP in cardiology and are identified as an effective tool for improving RP.

Radio-ecological characterization and radiological assessment in support of regulatory supervision of legacy sites in northwest Russia

The Norwegian Radiation Protection Authority has been implementing a regulatory cooperation program in the Russian Federation for over 10 years, as part of the Norwegian government's Plan of Action for enhancing nuclear and radiation safety in northwest Russia. The overall long-term objective has been the enhancement of safety culture and includes a special focus on regulatory supervision of nuclear legacy sites. The initial project outputs included appropriate regulatory threat assessments, to determine the hazardous situations and activities which are most in need of enhanced regulatory supervision. In turn, this has led to the development of new and updated norms and standards, and related regulatory procedures, necessary to address the often abnormal conditions at legacy sites.This paper presents the experience gained within the above program with regard to radio-ecological characterization of Sites of Temporary Storage for spent nuclear fuel and radioactive waste at Andreeva Bay and Gremikha in the Kola Peninsula in northwest Russia. Such characterization is necessary to support assessments of the current radiological situation and to support prospective assessments of its evolution. Both types of assessments contribute to regulatory supervision of the sites. Accordingly, they include assessments to support development of regulatory standards and guidance concerning: control of radiation exposures to workers during remediation operations; emergency preparedness and response; planned radionuclide releases to the environment; development of site restoration plans, and waste treatment and disposal. Examples of characterization work are presented which relate to terrestrial and marine environments at Andreeva Bay. The use of this data in assessments is illustrated by means of the visualization and assessment tool (DATAMAP) developed as part of the regulatory cooperation program, specifically to help control radiation exposure in operations and to support regulatory analysis of management options. For assessments of the current radiological situation, the types of data needed include information about the distribution of radionuclides in environmental media. For prognostic assessments, additional data are needed about the landscape features, on-shore and off-shore hydrology, geochemical properties of soils and sediments, and possible continuing source terms from continuing operations and on-site disposal. It is anticipated that shared international experience in legacy site characterization can be useful in the next steps. Although the output has been designed to support regulatory evaluation of these particular sites in northwest Russia, the methods and techniques are considered useful examples for application elsewhere, as well as providing relevant input to the International Atomic Energy Agency's international Working Forum for the Regulatory Supervision of Legacy Sites.

Monitoring human factor risk characteristics at nuclear legacy sites in northwest Russia in support of radiation safety regulation

This paper describes research aimed at improving regulatory supervision of radiation safety during work associated with the management of spent nuclear fuel and radioactive waste at legacy sites in northwest Russia through timely identification of employees presenting unfavourable human factor risk characteristics. The legacy sites of interest include sites of temporary storage now operated by SevRAO on behalf of Rosatom. The sites were previously operational bases for servicing nuclear powered submarines and are now subject to major remediation activities. These activities include hazardous operations for recovery of spent nuclear fuel and radioactive waste from sub-optimal storage conditions. The paper describes the results of analysis of methods, procedures, techniques and informational issues leading to the development of an expert-diagnostic information system for monitoring of workers involved in carrying out the most hazardous operations. The system serves as a tool for human factor and professional reliability risk monitoring and has been tested in practical working environments and implemented as part of regulatory supervision. The work has been carried out by the Burnasyan Federal Medical Biophysical Center, within the framework of the regulatory cooperation programme between the Federal Medical–Biological Agency of Russia and the Norwegian Radiation Protection Authority.

How 'do's' and 'dont's' can be of significant importance in radiation protection: a case report

The Norwegian Radiation Protection Authority (NRPA) was contacted by a cardiology department because of a suspicious radiation burn on a patient. The patient had undergone two bi-ventricular pacemaker implantations and the lesion was recognised as radiation dermatitis. The NRPA sent sets of thermoluminescense dosemeters to the department to measure the skin dose on eight successive patients undergoing bi-ventricular pacemaker implantations. The average maximum entrance surface dose for the eight patients was 5.3 Gy, ranging from 2.0 to 13.1 Gy. A site audit was performed during a procedure, with the aim to observe the general skills in radiation protection. Based on the findings in the audit, a few very simple 'Do's' and 'Don'ts' were highlighted in a meeting directly after the audit. After the audit, dose measurements were performed on six new patients showing an average maximum entrance surface dose of 0.4 Gy, ranging from 0.2 to 0.8 Gy. The aim of this work was to illustrate the dose reductions that are possible to achieve with a very few basic advices, especially when the operator has suboptimal competence.

Tracing carpenter ants (Camponotus sp.) in buildings with radioactive iodine 131I

Using radioactive iodine-labelled honey water, we traced carpenter ants (Camponotus sp.) in six buildings using a scintillation detector. The best trade-off obtained between safety and practicality was a 1-ml bait dose of 4 MBq 131I. The bait was placed close to an ant trail. A 4-MBq dose gave around 100 counts/s at the radioactive focus in the building, but fewer behind thick concrete structures where bait doses should be doubled. In two buildings, ant colonies were revealed at the radioactive foci. The radiation throughout the experiments never exceeded the limits set by the Norwegian Radiation Protection Authority (NRPA) for the public. Thus, use of radioactive iodine might be a powerful tool in research for investigating carpenter ant nesting behaviour in buildings.

Improvement of the dose assessment tools on the basis of dispersion of the99Tc in the Nordic Seas and the Arctic Ocean

Compartment models are widely used for the evaluation of radiological consequences to man and biota in the marine environment over large spatial and long temporal scales. The model developed at the Norwegian Radiation Protection Authority (NRPA) is based on a compartment modelling approach that includes terms describing dispersion of radionuclides into oceanic space with (non-instantaneous mixing in oceanic space). In this paper the latest modification of the NRPA model will be presented. The main improvement concerns the time of availability parameters (i.e. the times at which dispersed radionuclides reach compartment boundaries). The modifications have been implemented through the use of a comprehensive 99 Tc data set collected under the course of the project RADNOR and through comparison with the results of simulations provided by the 3D hydrodynamic NAOSIM model. The present version of the NRPA model describes the dispersion of 99 Tc in the Arctic Ocean and seas with a significantly improved precision for some marine regions. Results of the calculations indicate that defined time of availability parameters are in good agreement with transit times observed in the actual marine environment.

Overview of dose assessment developments and the health of riverside residents close to the "Mayak" PA facilities, Russia.

The Norwegian Radiation Protection Authority (NRPA) has been involved in studies related to the Mayak PA and the consequences of activities undertaken at the site for a number of years. This paper strives to present an overview of past and present activities at the Mayak PA and subsequent developments in the quantification of health effects on local populations caused by discharges of radioactive waste into the Techa River. Assessments of doses to affected populations have relied on the development of dose reconstruction techniques for both external and internal doses. Contamination levels are typically inhomogeneous and decrease with increasing distance from the discharge point. Citations made in this paper give a comprehensive, though not exhaustive, basis for further reading about this topic.

Strålebeskyttelse av barns bryst ved høyoppløselig CT av lungene

The Norwegian Radiation Protection Authority recommends bismuth to protect radiosensitive surface organs during CT imaging. A study based on the use of phantoms was therefore initiated to investigate the usefulness of this protection on the breasts of young girls undergoing high-resolution computed tomography (HRCT) of the chest. Shields covered with one, two or three layers of bismuth were placed on a homogenous phantom. CT numbers (pixel values in the images which describe the density of the tissue imaged), noise and artifacts were evaluated from the images of the phantom. Dosimeters were used for dose measurements in an anthropomorphic phantom of a child. Areas close to the shield in the images of the phantom had CT numbers up to 33 % higher with two and three layers of bismuth than in the images without shielding. With one layer the CT numbers were up to 8 % higher. Noise in the same area was up to 56 % higher with two and three layers of bismuth than without, and up to 14 % higher with one layer. The surface dose in the breast region was reduced with 30 % with one layer of bismuth, 45 % with two and 75 % with three layers of bismuth. Shielding with one layer of bismuth seems to have little effect on the CT images. The Department of pediatric radiology at Ullevaal University Hospital now uses bismuth protection with one layer as a routine during HRCT of girls up to 16 years of age.

Radioecological consequences of a potential accident during transport of spent nuclear fuel along an Arctic coastline

This article presents results pertaining to a risk assessment of the potential consequences of a hypothetical accident occurring during the transportation by ship of spent nuclear fuel (SNF) along an Arctic coastline. The findings are based on modelling of potential releases of radionuclides, radionuclide transport and uptake in the marine environment. Modelling work has been done using a revised box model developed at the Norwegian Radiation Protection Authority. Evaluation of the radioecological consequences of a potential accident in the southern part of the Norwegian Current has been made on the basis of calculated collective dose to man, individual doses for the critical group, concentrations of radionuclides in seafood and doses to marine organisms. The results of the calculations indicate a large variability in the investigated parameters above mentioned. On the basis of the calculated parameters the maximum total activity (“accepted accident activity”) in the ship, when the parameters that describe the consequences after the examined potential accident are still in agreement with the recommendations and criterions for protection of the human population and the environment, has been evaluated.

Radiological protection regulation during spent nuclear fuel and radioactive wastemanagement in the Western Branch of the Federal State Unitary Enterprise ‘SevRAO’

The site of temporary storage of spent nuclear fuel and radioactive waste, situated atAndreeva Bay in Northwest Russia, was developed in the 1960s, and it has carried outreceipt and storage of fresh and spent nuclear fuel, and solid and liquid radioactive wastegenerated during the operation of nuclear submarines and nuclear-powered icebreakers.The site is now operated as the western branch of the Federal State UnitaryEnterprise, SevRAO. In the course of operation over several decades, the containmentbarriers in the Spent Nuclear Fuel and Radioactive Waste storage facilities partiallylost their containment effectiveness, so workshop facilities and parts of the sitebecame contaminated with radioactive substances. This paper describes work beingundertaken to provide an updated regulatory basis for the protection of workers duringespecially hazardous remediation activities, necessary because of the unusual radiationconditions at the site. It describes the results of recent survey work carried outby the Burnasyan Federal Medical Biophysical Centre, within a programme ofregulatory cooperation between the Norwegian Radiation Protection Authority and theFederal Medical–Biological Agency of Russia. The survey work and subsequentanalyses have contributed to the development of special regulations setting outradiological protection requirements for operations planned at the site. Within theserequirements, and taking account of a variety of other factors, a continuing needarises for the implementation of optimisation of remediation at Andreeva Bay.

Medical and radiological aspects of emergency preparedness and response at SevRAOfacilities

Regulatory cooperation between the Norwegian Radiation Protection Authority and theFederal Medical Biological Agency (FMBA) of the Russian Federation has the overall goalof promoting improvements in radiation protection in Northwest Russia. One of theprojects in this programme has the objectives to review and improve the existing medicalemergency preparedness capabilities at the sites for temporary storage of spent nuclear fueland radioactive waste. These are operated by SevRAO at Andreeva Bay and in Gremikhavillage on the Kola Peninsula. The work is also intended to provide a better basis forregulation of emergency response and medical emergency preparedness at similar facilitieselsewhere in Russia. The purpose of this paper is to present the main results ofthat project, implemented by the Burnasyan Federal Medical Biophysical Centre.The first task was an analysis of the regulatory requirements and the currentstate of preparedness for medical emergency response at the SevRAO facilities.Although Russian regulatory documents are mostly consistent with internationalrecommendations, some distinctions lead to numerical differences in operationalintervention criteria under otherwise similar conditions. Radiological threats relating topossible accidents, and related gaps in the regulation of SevRAO facilities, were alsoidentified. As part of the project, a special exercise on emergency medical responseon-site at Andreeva Bay was prepared and carried out, and recommendations wereproposed after the exercise. Following fruitful dialogue among regulators, designersand operators, special regulatory guidance has been issued by FMBA to accountfor the specific and unusual features of the SevRAO facilities. Detailed sectionsrelate to the prevention of accidents, and emergency preparedness and response,supplementing the basic Russian regulatory requirements. Overall it is concludedthat (a) the provision of medical and sanitary components of emergency responseat SevRAO facilities is a priority task within the general system of emergencypreparedness; (b) there is an effective and improving interaction between SevRAO and thelocal medical institutions of FMBA and other territorial medical units; (c) theinfrastructure of emergency response at SevRAO facilities has been created andoperates within the framework of Russian legal and normative requirements. Furtherproposals have been made aimed at increasing the effectiveness of the availablesystem of emergency preparedness and response, and to promote interagencycooperation.

Method for efficient establishment of technical biodosimetry competence

The current gold standard in biodosimetry, the dicentric assay, requires documented technical competence. Expertise is developed over time by evaluation of thousands of metaphases. Competence is documented through establishment of a dose–response curve, required by any service laboratory performing biodosimetry. Consistent and reliable evaluations must be established for new observers that might contribute to analyses for biological dose assessments. Discrepancies in evaluations jeopardize the reliability of assessments. The Swedish Defence Research Agency (FOI) together with the Norwegian Radiation Protection Authority (NRPA) conducted an inter-calibration exercise for the purpose of establishing comparable scoring criteria for evaluation of aberrations in metaphases. The exercise revealed specific aberrations that were difficult to identify and were consistent sources of uncertainty. Subsequently, a report detailing the FOI's scoring criteria was developed with visual examples and a strategy for establishing technical competence in metaphase scoring in an efficient manner evolved. Key components of the strategy are the review of guidance for biodosimetry, performance of inter-calibration exercises with previously established data sets, review of incongruous evaluations with a well-established observer, follow-up exercises depending on the initial outcome, and inter-comparisons to document agreement. Methods suggested here could be applied in training of new personnel. Documentation of methods in other laboratories could facilitate more consistent scoring criteria among the biodosimetry community, a problem observed in previous international inter-comparisons. Improved consistency among biodosimetry laboratories could facilitate reliably sharing the work load among different members of the biodosimetry community in the event of a mass casualty accident.

Geographical variation in radiological services: a nationwide survey

BackgroundGeographical variation in health care services challenges the basic principle of fair allocation of health care resources. This study aimed to investigate geographical variation in the use of X-ray, CT, MRI and Ultrasound examinations in Norway, the contribution from public and private institutions, and the impact of accessibility and socioeconomic factors on variation in examination rates.MethodsA nationwide survey of activity in all radiological institutions for the year 2002 was used to compare the rates per thousand of examinations in the counties. The data format was files/printouts where the examinations were recorded according to a code system.ResultsOverall rates per thousand of radiological examinations varied by a factor of 2.4. The use of MRI varied from 170 to 2, and CT from 216 to 56 examinations per 1000 inhabitants. Single MRI examinations (knee, cervical spine and head/brain) ranged high in variation, as did certain other spine examinations. For examination of specific organs, the counties' use of one modality was positively correlated with the use of other modalities. Private institutions accounted for 28% of all examinations, and tended towards performing a higher proportion of single examinations with high variability. Indicators of accessibility correlated positively to variation in examination rates, partly due to the figures from the county of Oslo. Correlations between examination rates and socioeconomic factors were also highly influenced by the figures from this county.ConclusionThe counties use of radiological services varied substantially, especially CT and MRI examinations. A likely cause of the variation is differences in accessibility. The coexistence of public and private institutions may be a source of variability, along with socioeconomic factors. The findings represent a challenge to the objective of equality in access to health care services, and indicate a potential for better allocation of overall health care resources.Previous publicationThe data applied in this article was originally published in Norwegian in: Børretzen I, Lysdahl KB, Olerud HM: Radiologi i Noreg – undersøkingsfrekvens per 2002, tidstrendar, geografisk variasjon og befolkningsdose. StrålevernRapport 2006:6. Østerås: The Norwegian Radiation Protection Authority. The Norwegian Radiation Protection Authority has given the authors permission to republish the data.

Shift in imaging modalities of the spine through 25 years and its impact on patient ionizing radiation doses

Study designRetrospective. ObjectiveTo explore the shift in modalities when diagnosing the spine in the years 1979–2003. To see how this shift, together with a radiation protective policy, have influenced on the ionizing radiation doses. Summary of background dataThe shift from CT/myelography to MR when diagnosing the spine is well known. To what extent this has changed the radiation doses has to our knowledge not yet been published. MethodsActivity reports from a department of radiology have been reviewed. Relevant radiation doses estimates have been obtained from the Norwegian Radiation Protection Authority. ResultsMRI was introduced in 1992 and has been used increasingly since then. Conventional X-ray to the spine has been practically unchanged. Myelography and CT decreased markedly after the introduction of MRI. The total number of examinations of the spine has increased, but the radiation doses given have decreased since 1993. ConclusionsThe introduction of MRI together with a radiation protective policy have reduced the ionizing radiation doses given to this population, in spite of an increase in the total number of examinations of the spine.

Measurements of finger doses in x-ray guided surgery, nuclear medicine and research

The Norwegian Radiation Protection Authority has performed measurements of finger doses to nuclear medicine staff exposed to 99Tc(m), researchers handling 32P, surgeons performing X-ray guided orthopaedic surgery and surgeons and radiologists performing X-ray guided endovascular treatment of abdominal aortic aneurysms (AAA). Calibrations were done with X-ray qualities N-40, N-60 and N-300 and with the beta source 90Sr + 90Y. Annual doses were estimated for the nuclear medicine staff and the orthopaedic surgeons. The mean annual finger dose to nuclear medicine staff exposed to 99Tc(m) was estimated to be 18.8 mSv, and the mean annual finger dose to surgeons performing X-ray guided orthopaedic surgery was 13.7 mSv. The surgeons and radiologists performing X-ray guided endovascular treatment of AAA received a mean finger dose of 0.35 mSv per treatment. The majority of researchers handling 32P received no finger dose at all, and the maximum reading was 1.65 mSv. All occupational groups received finger doses well below the annual finger dose limit of 500 mSv.

Geostatistical analysis as applied to two environmental radiometric time series.

This article details the results of an investigation into the application of geostatistical data analysis to two environmental radiometric time series. The data series employed consist of 99Tc values for seaweed (Fucus vesiculosus) and seawater samples taken as part of a marine monitoring program conducted on the coast of northern Norway by the Norwegian Radiation Protection Authority. Geostatistical methods were selected in order to provide information on values of the variables at unsampled times and to investigate the temporal correlation exhibited by the data sets. This information is of use in the optimisation of future sampling schemes and for providing information on the temporal behaviour of the variables in question that may not be obtained during a cursory analysis. The results indicate a high degree of temporal correlation within the data sets, the correlation for the seawater and seaweed data being modelled with an exponential and linear function, respectively. The semi-variogram for the seawater data indicates a temporal range of correlation of approximately 395 days with no apparent random component to the overall variance structure and was described best by an exponential function. The temporal structure of the seaweed data was best modelled by a linear function with a small nugget component. Evidence of drift was present in both semi-variograms. Interpolation of the data sets using the fitted models and a simple kriging procedure were compared, using a cross-validation procedure, with simple linear interpolation. Results of this exercise indicate that, for the seawater data, the kriging procedure outperformed the simple interpolation with respect to error distribution and correlation of estimates with actual values. Using the unbounded linear model with the seaweed data produced estimates that were only marginally better than those produced by the simple interpolation.