The radioactivity concentrations of 226Ra, 232Th and 40K were measured using gamma-ray spectroscopy with NaI (Tl) detectors in four tantalite mining sites in the Oke-Ogun area, South-Western Nigeria. The measured values of the activities of 40K, 226Ra and 232Th in the soil samples were found to lie in the ranges 123.7 ± 3.8 – 1372.3 ± 8.6, 16.8 ± 1.6 – 71.1 ± 2.53 and 3.0 ± 0.7 – 31.9 ± 1.0 Bq kg–1, respectively. These samples were also found to have radium equivalent activity in the range 74.2–121.0 Bq kg-1. Values of 0.2–0.3 for the external and 0.3–0.4 for the internal hazard indices were estimated for the samples and the annual effective dose varied from 70.3 ± 13.5 to 100.8 ± 42.8 µSv with a mean of 87.5 ± 18.6 µSv y–1. The annual effective dose is higher than the world average.

Radon-222 exhalation from different ceramic tiles depends upon the radium (226Ra) concentration and porosity. Raw zirconium sand is one of the substances widely used in the ceramic industry and it is naturally radioactive. This can produce unjustified concern and subsequently perturb the market of these products. The radon exhalation rates for all ceramic tile companies were in the ranges 28-44 mBq.m-2.h-1 and 2.0 to 4.8 mBq.kg-1 .h-1. The porosity of ceramic tiles is in the range 0.19-0.28. The radium activity of ceramic tiles was found to be in the range 16-38 Bq.kg-1 for the glazed surface and 23-64 Bq.kg-1 for the clay surface, respectively. The average equivalent dose in contact with the ceramic surface was found to be 22 mSv.y-1. The exposure at working level at the ceramic tile surface was in the range 2.4-3.8 WL. This gives a risk indication to people who spend a long time in closed ceramic tile stores, who should avoid staying for a long time in such places.

Accurate dose calculations are very important in radiotherapy treatment planning. The Monte Carlo method has proven to be an accurate and reliable method for simulation of the dose distributions from electron beams and can provide theoretically more accurate distributions than conventional planning system algorithms (e.g. the Generalized Gaussian Pencil Beam algorithm) for more complex target configurations. The aim of this work was to assess the parameters and spectrum of a given electron beam (Varian CLINAC 2100 C/D) from experimental depth dose distribution and then simulate dose distributions in an experimental arrangement with a 3D polymer gel dosimeter. The comparison of data from experimental measurements, Monte Carlo calculations and the planning system enabled us to verify experimentally the simulation model and technique as well as the planning system results. Both simple and more complex systems (e.g. dose distributions close to different material interfaces) can be studied. The generation and influence of the “bremsstrahlung” photons in the electron beams was also analyzed using the simulation technique. The computations, experimental methods used and results obtained are presented and discussed.

In order to study the vertical migration of anthropogenic 137Cs, soil inventories of this radionuclide were measured in two regions selected on the basis of a previous comprehensive survey in the northern Iranian province of Guilan located in the South Caspian region. Ten sampl ing stations were randomly chosen in these regions and split-level sampling was carried out to a depth of 30 cm. Sample analysis was performed using a HPGe detector system. In situ gamma measurements in both regions were als o carried out with the aid of a portable germanium spectrometer. The experimental data were then compared with the solution of the convection-dispersion equation (CDE) with the proper initial and boundary conditions to evaluate initial deposition as well as transport parameter values. The solution, including the effects of both considered sources, i.e. global fallout and Chernobyl releases, fits the measured data well. The effective convection velocity and dispersion coefficients of 137Cs lie in the range of 0-0.25 cm·y-1 and 0.32-0.75 cm2·y-1, respectively, indicating a very slow migrat ion rate in the area. Most of the deposited 137Cs still remained in the top 10-cm layer. Moreover, the fitted depth profiles were then employed to correct the surface activities of 137Cs estimated by in situ measurements.

We performed an Environmental Risk Assessment (ERA) to evaluate the impact on non-human biota from liquid radioactive effluents discharged by the Belgian Nuclear Power Plants (NPPs) of Doel and Tihange. A deterministic risk assessment for aquatic and terrestrial ecosystems was performed using the ERICA tool and applying the ERICA screening value of 10 µGy.h-1. The ERA was performed for the radioactive discharge limits and for the actual releases (maxima and averages over the last 10 years, 1999-2008). All ERICA reference organisms were considered and depending on the assessment situation, additional reference organisms were included in the analysis. It can be concluded that the current discharge limits for the Belgian NPPs do not result in significant risks to the aquatic and terrestrial environment and that the actual discharges, which are a fraction of the liquid discharge limits, are unlikely to harm the environment.

In pediatric radiology, radiological protection is of vital importance due to the great radio-sensitivity of body tissues in childhood, which can come to present stochastic effects as children have a longer life expectancy. The objective of this research is to establish diagnostic reference levels in chest exam pediatric patients. The study, carried out in one of the largest pediatric centers of the city of Medellin, the capital of the Department of Antioquia, consisted of the calculation of the Entrance Skin Dose (ESD) for a sample of 814 chest radiographic studies in the anteroposterior (AP) and left lateral (L LAT) projections, and it was compared with the doses obtained with the computational program PCXMC 2.0. For the estimate of the Entrance Skin Dose, data were collected from the exams, including the size of the radiation field, mAs and kVp. The ESD in chest exams for 5-year-old children was the only one that exceeded the international reference levels, giving evidence of the need to optimize the techniques used in this type of study in the institution under evaluation.

Interventional cardiology procedures can involve potentially high doses of radiation to the patients. Stochastic effects of ionising radiation – radiation-induced cancers in the long term – may occur. We analysed clinical characteristics and dosimetric data in a population of patients undergoing interventional cardiology. In all, 1 591 patients who had undergone coronarography and/or angioplasty in the course of a year at the Saint-Gatien Clinic in Tours (France) were included. Information on patients’ individual clinical characteristics and Dose-Area Product values were collected. Organ doses to the lung, oesophagus, bone marrow and breast were mathematically evaluated. The median age of patients was 70 years. Their median cumulative dose-area product value was 48.4 Gy.cm2 for the whole year and the median effective dose was 9.7 mSv. The median organ doses were 41 mGy for the lung, 31 mGy for the oesophagus, 10 mGy for the bone marrow and 4 mGy for the breast. Levels of doses close to the heart appear to be rather high in the case of repeated interventional cardiology procedures. Clinical characteristics should be taken into account when planning epidemiological studies on potential radiation-induced cancers.

Inhalation of indoor radon has been recognized as the largest contributor to the total effective dose received by human beings. Indoor radon data were collected from the dwellings lying on the sedimentary rocks (sandstones, siltstones and clays) of the Murree Formation, Nagri Formation, Dhok Pathan Formation, Mirpur conglomerate and surficial deposits of the Kotli area in Azad Jammu and Kashmir, Pakistan. Radon measurements were made using the passive time-integrated method using Kodak CN-85 Solid-State Nuclear Track Detectors. The radon concentration in dwellings varied from 13 ± 6 Bq.m-3 to 185 ± 23 B. qm-3, with an average of 73 ± 15 Bq.m-3.The radon concentration in the Murree Formation, Nagri Formation, river terrace and Dhok Pathan Formation were 89.7 ± 16.5, 72 ± 15, 68.5 and 69 Bq.m-3, respectively. The average value of all the measured concentrations (73 ± 15 Bq.m-3) within the framework of this study is more than the world average value of 40 Bq.m-3 given by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation, report to the General Assembly, United Nations, New York, 2000) and is within the action level of 200-600 Bq.m-3 fixed by the ICRP(International Commission on Radiological Protection, ICRP publication65, Protection against radon at home and at work, 1993). The ambient gamma dose rates both indoors and outdoors in different parts of Kotli were also measured. The average value of gamma absorbed dose rates prevailing in the indoor environment was 131.2 ± 16.6 nGy/h. The gamma exposure rates recorded outdoors were 35% lower than in the indoor environment. The measured gamma dose rates have a weak positive correlation with indoor radon concentration. The annual effective dose for inhabitants in Kotli due to radon ranged from 0.32 to 4.7 mSv.y-1, with an average value of 1.8 mSv.y-1. This dose is relatively higher than the world mean dose of 1.15 mSv/y. That is explained by the particular geology of the state of Azad Jammu and Kashmir, and the method of construction of the dwellings.

The study of radiation fields around the cyclotron room was carried out for the Proton-Therapy-Center in Prague (Czech Republic). The 230 MeV proton cyclotron will be installed there as well as additional components located along the beampath. The ambient doses were computed by taking into account 3 major sources of secondary radiation (neutron and photon) – the cyclotron, energy degrader and its collimator. The fluxes of neutrons/photons produced by protons were computed using Monte Carlo code MCNPXTM 2.5.0. Energy and angular distributions were computed for various targets and proton beam energies. Different physical models of high-energy proton interactions were studied as well. The annual charge at the cyclotron exit was based on the “patient model” (distribution of treatment type) established for a similar therapy center in Essen (Germany). Calculated data were used as an approximation of the radiation field of the most significant sources of radiation (graphite degrader, tantalum collimator). Fluence-to-dose conversion factors from ICRP-74 were used for the annual dose equivalent evaluation. With these results, the shielding analysis in the Therapy-Center was performed in the context of the current legislation requirements.

The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011 led to an unprecedented direct input of artificial radioactivity into the marine environment. The Institute for Radioprotection and Nuclear Safety was requested by the French authorities to investigate the radioecological impact of this input, in particular the potential contamination of products of marine origin used for human consumption. This article describes the close link between the responses provided and the availability of the data, as well as their nature and ability to meet the requirements of expert investigation. These responses were needed: (i) to evaluate the inputs of radionuclides into the marine environment, (ii) to understand their dispersion in seawater, and (iii) to estimate their transfer to the biota and sediments. Three phases can be distinguished which characterise these processes during the accident and post-accident periods. The first phase corresponds to an emergency phase during which no measurements were available on samples from the marine environment. It involved the formulation of hypotheses based solely on the expertise of the Institute for Radioprotection and Nuclear Safety. The second phase started when the Japanese authorities provided measurements of the concentrations of radionuclides in seawater. Although these data were not yet adapted to addressing the problems of radioecology, the scenarios could then be refined and the estimates developed in more detail. During the third phase, the accumulation of data over the course of time made it possible to study the phenomena in an appropriate way. The chronology of the events shows that it is essential to have (i) significant measurements of concentration from samples collected in the various matrices of the marine environment, regularly updated and sufficiently well-documented, (ii) samples of seawater collected at the earliest opportunity as close as possible to the damaged site to characterise the source term, and (iii) a numerical tool allowing rapid modelling of the dispersion of radionuclides in seawater, as well as their transfer to sediments and the biota, ultimately for the purpose of estimating the dose to humans.

The natural γ-radiation in samples of a variety of marbles imported into Bangladesh for use in building construction was measured, employing γ-ray spectrometry with a HPGe detector. From the measured γ-ray spectra, activity concentrations were determined for 226Ra (29.31 ± 2.06 to 46.99 ± 2.97 Bq.kg–1), 232Th (42.91 ± 2.53 to 62.92 ± 3.37 Bq.kg–1) and 40K (824.42 ± 15.42 to 1071.58 ± 20.14 Bq.kg–1). The measured activity concentrations for these natural radionuclides were compared with the reported data of other countries and with the world average activity of soil. The radium equivalent activity (Raeq), the hazard indices, the gamma activity concentration index, the indoor absorbed dose rate and the corresponding annual effective dose were estimated for the potential radiological hazard of the marble. The Raeq values of all marble samples are lower than the limit of 370 Bq.kg–1, equivalent to a dose of 1.5 mSv.y–1. The average values of the external and internal hazard indices are less than unity. The average indoor absorbed dose rate (121.25 nGy.h–1) is higher than the population-weighted average of 84 nGy.h–1, whereas the corresponding annual dose limit falls within an average value of 0.60 mSv, which is an order of magnitude below the limit specified for building materials in the literature. The present results indicate that using marble in building construction in Bangladesh does not pose any significant radiological hazard.

Calculations are presented of the effective doses per unit neutron fluence according to the ICRP publications 60 and 103. Monte Carlo N-Particle (MCNPX) code was used for six geometrical conditions of irradiation (Anterior-Posterior, Posterior-Anterior, Left-Lateral, Right-Lateral, Rotation and Isotropic) on Oak Ridge National Laboratory (ORNL) modified mathematical adult phantoms for monoenergetic neutrons from 10-9 MeV to 20 MeV. The conversion coefficients were compared with the results of an analytical phantom (Medical Internal Radiation Dose (MIRD-5)) and some voxel model (ICRP/ICRU Reference Voxel Phantom (ICRP/ICRU RVP), HANAKO, TARO and Visible Human Project (VIPMAN)). From these comparisons, one can conclude that large discrepancies between data sets appear when wR and different sizes of the phantoms have been used for calculations. Furthermore, the differences in applied Monte Carlo codes or simulated body models could make some discrepancies less than 15%.

In the framework of assistance for Japan, the ACTIFLORAD project for liquid waste decontamination mobilized over 200 AREVA collaborators and 47 people who led their mission in the damaged site. Led between May 18th and July 6th, 2011, the French mission aimed at supervising the ACTIFLORAD process building and assisting Japanese teams in performing it. The post-accidental situation and emergency led to setting up a radiation protection organization in agreement with French regulation as well as integrated into the Japanese organization. This text establishes a testimony of the everyday life of the mission and its preliminary preparation.

L’acquisition du mouvement est de plus en plus souvent effectuée pour améliorer la balistique des traitements en radiothérapie externe. Cependant, elle est source d’une exposition supplémentaire pour le patient. Le développement de la plate-forme de simulation numérique NEMOSIS (NEural NEtwork MOtion SImulation System) ouvre la voie à l’optimisation de la dose en imagerie. Elle permet de générer un mouvement pulmonaire localisé et personnalisé à partir du modèle 3D du patient. Pour 3 patients test, 5 à 6 points anatomiques ont été simulés puis comparés aux tracés du radiothérapeute. Dans le cas le plus défavorable, les résultats ont montré une précision moyennée sur l’ensemble des points d’un patient et sur toutes les phases d’environ 3 mm avec une incertitude élargie de tracé égale à 1,5 mm (intervalle de confiance de 95 %) et une incertitude maximale de phase atteignant 6,53 mm. Une autre étude comparant les GTV ( Gross Tumor Volume) d’un radiothérapeute et ceux calculés par NEMOSIS a été également menée. Un indice de Dice stipulant une correspondance minimale de 0,80 a été calculé entre les deux types de volumes. Ces résultats font de NEMOSIS un outil très prometteur en tant qu’alternative aux imageries irradiantes.

The assessment of the radiological impact of a decommissioned nuclear power plant is presented here through the results of an environmental monitoring survey carried out in the area surrounding the Garigliano Power Plant. The levels of radioactivity in soil, water, air and other environmental matrices are shown, in which α, β and γ activity and the γ equivalent dose rate are measured. Radioactivity levels of the samples from the Garigliano area are analyzed and then compared with those from a control zone situated more than 100 km away. Moreover, a comparison is made with a previous survey carried out in 2001. The analyses and comparisons show no significant alteration in the radiological characteristics of the area surrounding the plant, with the overall radioactivity depending mainly on the global fallout and natural sources.

A workshop dedicated to cancer risks associated with low-dose internal contamination was organised in March 2011, in Paris, in the framework of the DoReMi (Low Dose Research towards Multidisciplinary Integration) European Network of Excellence. The aim was to identify the best epidemiological studies that provide an opportunity to develop a multidisciplinary approach to improve the evaluation of the cancer risk associated with internal contamination. This workshop provided an opportunity for in-depth discussions between researchers working in different fields including (but not limited to) epidemiology, dosimetry, biology and toxicology. Discussions confirmed the importance of research on the health effects of internal contamination. Several existing epidemiological studies provide a real possibility to improve the quantification of cancer risk associated with internal emitters. Areas for future multidisciplinary collaborations were identified, that should allow feasibility studies to be carried out in the near future. The goal of this paper is to present an overview of the presentations and discussions that took place during this workshop.

En France, les effluents générés par des personnes traitées et hospitalisées en médecine nucléaire doivent être collectés dans des cuves de décroissance avant leur rejet dans le réseau d’assainissement, en accord avec les limites règlementaires définies. Un modèle utilisant une série d’exponentielle décroissante a été mis au point permettant de simuler l’évolution de l’activité volumique dans les cuves de décroissance. Ainsi son utilisation permet d’optimiser le nombre et la capacité des cuves par rapport à l’activité médicale actuelle ou future. En outre, ce modèle est très modulable puisqu’il intègre comme variables : la période physique du radioélément, le volume total de chaque cuve, l’activité excrétée par patient, le volume total d’effluents générés par patient durant son séjour en chambre blindée, le nombre de patients pris en charge lors de chaque semaine et le nombre de semaines avant la mise en décroissance de la cuve. Par ailleurs, les simulations avec ce modèle montrent qu’à activité médicale équivalente, il est possible de travailler soit avec 2 grandes cuves soit avec 3 cuves ayant une capacité réduite de 50 %. L’utilisation de plusieurs petites cuves permet en outre de maintenir la rotation des cuves de décroissance en cas de mise hors service d’une d’entre elles.

Après le passage du tsunami les sous-sols des bâtiments de la centrale étaient envahis par de l’eau de mer plus ou moins contaminée. L’eau d’arrosage des réacteurs accidentés s’y ajoutant, l’opérateur de la centrale s’est trouvé face à la menace d’un débordement général à brève échéance. Les groupes français AREVA et Veolia ainsi que la société américaine Kurion sont intervenus pour réaliser sur site et dans l’urgence une installation de décontamination de grande capacité. Kurion a fourni le premier étage du traitement, par échangeurs minéraux en cartouches blindées. AREVA et Veolia ont associé leurs compétences pour mettre en œuvre le procédé chimique de décontamination de Marcoule et La Hague dans des machines Veolia prévues pour le traitement d’effluents non radioactifs. Malgré l’ampleur des innovations nécessaires, et les conditions de travail sur site difficiles et changeantes, le traitement des effluents est devenu opérationnel en moins de trois mois, et a permis d’éviter le débordement.