The paper presents the results of radiocarbon (14C) concentration measurements in tree rings in the vicinity of Kursk NPP (Russia) with four operating RBMK reactors. The sampling was carried out from the site with the highest expected accumulation of radiocarbon in vegetation. The site was determined with long-term meteorological data. The measurements of 14C concentration carried out with accelerator-mass spectrometer in Budker Institute of Nuclear Physics, Novosibirsk, Russia. The obtained results demonstrated the influence of exploitation of Kursk NPP to the concentration of 14C in tree rings. Based on the equilibrium between the 14C ratio in the tree rings and the surrounding air, retrospective estimates of the radiocarbon discharge and effective doses were made. Effective doses were calculated with two approaches: IAEA methodology and less conservative approach, considering the real food consumption in the Kursk region. The values of calculated doses by the second method (0.08–2.58 μSv) are more than 2 times less than IAEA approach (0.17–5.30 μSv). The highest difference between measured and background 14C in tree ring is 41.7 ± 5.8 pMC in 2014 during the restoration of graphite stack. The main contribution to 14С exposure in the considering period is caused by background – from 70 to 99%.

Tolpyralate is an herbicide that is usually mixed with atrazine for broad-spectrum weed control in corn. Previous research has provided information on the effective dose (ED) of tolpyralate applied alone and in a 1:33.3 mixture with atrazine; however, tolpyralate is commercially applied at a dose of 30 to 40 g ai ha−1 with a minimum of 560 g ai ha−1 of atrazine. Therefore, five field trials were conducted over 3 yr (2019 to 2021) to determine the ED of atrazine to complement 30 g ai ha−1 of tolpyralate to achieve 80%, 90%, and 95% control of seven weed species 2, 4, and 8 wk after application (WAA). Tolpyralate was applied alone and in a mixture with atrazine doses ranging from 50 to 2,000 g ai ha−1. At 8 WAA, the ED of atrazine for 95% control of velvetleaf, common ragweed, common lambsquarters, and wild mustard was below the minimum label dose of atrazine on the commercial tolpyralate label, ranging from 430 to 520 g ai ha−1, which supports the use of the minimum label dose of atrazine. In contrast, redroot pigweed required 1,231 g ai ha−1 of atrazine to complement tolpyralate for 95% control 8 WAA. At 8 WAA, barnyardgrass and a mixture of green foxtail and giant foxtail (Setaria spp.) were not controlled by 80%, 90%, or 95% with tolpyralate applied alone or co-applied with any dose of atrazine evaluated in this study. The results of this study conclude that tolpyralate + atrazine is highly efficacious on several weed species at atrazine doses of 40 to 130 g ai ha−1 below the label dose of 560 g ai ha−1, but the use of the higher dose of tolpyralate or another herbicide may be required to improve control of redroot pigweed and grass weed species.

Areas affected by routine radiocarbon (14C) discharges from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) and accidental releases in March 2011 were investigated by analysis of cores from Japanese cypress and cedar trees growing at sites 9 and 24 km northwest of the plant. 14C concentrations in tree rings from 2008–2014 (before and after the accident) were determined by accelerator mass spectrometry, with 14C activities in the range 231–256 Bq kg−1 C. Activities during the period 2012–2014, after FDNPP shutdown, represent background levels, while the significantly higher levels recorded during 2008–2010, before the accident, indicate uptake of 14C from routine FDNPP operations. The mean excess 14C activity for the pre-accident period at the sites 9 and 24 km northwest of the plant were 21 and 12 Bq kg−1 C, respectively, indicating that the area of influence during routine FDNPP operations extended at least 24 km northwest. The mean excess tree-ring 14C activities in 2011 were 10 and 5.8 Bq kg−1 C at 9 and 24 km northwest, respectively, documenting possible impact of the FDNPP accident on 14C levels in trees.

CT scanning technology is a valuable tool to diagnose many diseases; however, the levelof the radiation dose is a source of concern, especially for children. CT scan systems anddose measurement methods have evolved over the years; but reported pediatric effectivedoses (EDs) have sometimes exceeded the annual dose limit recommended by the ICRP (1 mSvper year for persons under 18 years) (ICRP, 2007a).Efforts have been made to reduce organ doses and EDs by adjusting the scan parameters.This paper describes the determinants of the ED, and the dose reduction techniques inpediatric imaging from the early age of CT examinations until now. The firstepidemiological results regarding the associated risk of cancer are also brieflypresented.

In this paper, the effect of additional adipose and muscle layers was investigated on theeffective dose and the organ absorbed dose. Calculations were performed using the MonteCarlo N-Particle Transport Code (MCNP) and the ORNL mathematical phantom for externalphoton and neutron beams. Variations in adipose and muscle tissue thickness were modeledby adding layers of adipose and soft tissues around the torso of the phantom. Theeffective dose decreased by about 7%–40% when the thickness of the extra layer increasedfrom 0.5 to 5 cm considering all photon energies (10 keV–10 MeV) and neutron energies(10–9–20 MeV) for anterior-posterior, posterior-anterior, left-lateral,right-lateral, rotation and isotropic irradiation geometries. The results calculated herewere compared with those reported in previous studies such as those of the VIPMAN,NORMAN05, MASH-3 and ICRP reference voxel phantoms. Our data shows that adding properadipose or muscle layers to two very different phantoms can cause similar effective dosevalues, and also more than half of the organ absorbed doses have satisfactoryagreement.

Indoor radon concentrations were measured in four well-known spas of Tunisia usingnuclear track detectors. The radon concentrations in these spas were found to be in therange of 19 - 870 Bq.m-3. The equilibrium factor F between radon and itsprogeny was found to vary in the range of 0.2 - 0.5, depending upon the ventilation rateswithin the buildings of the spas. Using the exposure-dose conversion factor, the effectivedoses to patients and workers were estimated and the dose was found to vary in the range3.7 × 10-3 - 12.5 × 10-3 mSv.y-1 and 0.45 - 1.5 mSv.y-1for patients and workers, respectively. These values are well inside the limit recommendedfor the annual dose limit of 20 mSv.y-1 for an occupational worker. The radiumcontent in the groundwater of all four spas was measured and the results showed nocorrelation between the 226Ra concentration in water and radon concentration inindoor air of the investigated spas.

La contamination radioactive, qu’elle soit de nature surfacique ou atmosphérique, peutêtre la cause d’une exposition interne de l’individu. Les valeurs Limites pratiques deconcentration dans l’air (LPCA) permettent aux médecins du travail ainsi qu’aux Personnescompétentes en Radioprotection (PCR) de pré-évaluer les risques résultant d’unecontamination atmosphérique. Ces valeurs sont utilisées pour déterminer la conduite àtenir au poste de travail mais aussi comme outil d’optimisation de la protection despersonnes dans le cadre de l’application du principe ALARA (As Low As ReasonablyAchievable). Lors des analyses de poste, les PCR des laboratoires Pierre Fabre ont étéconfrontées à des valeurs de dose efficace engagée qui semblaient, de leur point de vue,anormalement élevées. Ces valeurs étaient en contradiction avec les résultats des examensde radiotoxicologie urinaire réalisés dans le cadre de la surveillance médicale renforcéedes manipulateurs, qui se sont toujours avérés négatifs (que ces examens soient effectuéspériodiquement ou de façon ponctuelle à la fin d’une série de manipulations radioactives).C’est pourquoi il a été jugé pertinent de louer des systèmes de barboteurs, équipementsutilisés pour la surveillance des faibles niveaux de concentration en tritium et carbone14. Les mesures réalisées ont permis de mettre en évidence des niveaux de contaminationatmosphérique en tritium négligeables, notamment lors des étapes de manipulation jugéesa priori pénalisantes. Ce travail, mené dans le cadre des études deposte, nous a permis d’abaisser la valeur du facteur de volatilité des composés tritiésintervenant dans le calcul de dose efficace engagée.

The radioactivity concentrations of 226Ra, 232Th and 40Kwere measured using gamma-ray spectroscopy with NaI (Tl) detectors in four tantalitemining sites in the Oke-Ogun area, South-Western Nigeria. The measured values of theactivities of 40K, 226Ra and 232Th in the soil sampleswere found to lie in the ranges 123.7 ± 3.8 – 1372.3 ± 8.6, 16.8 ± 1.6 – 71.1 ± 2.53 and3.0 ± 0.7 – 31.9 ± 1.0 Bq kg–1, respectively. These samples were also found to have radiumequivalent activity in the range 74.2–121.0 Bq kg-1. Values of 0.2–0.3 for the externaland 0.3–0.4 for the internal hazard indices were estimated for the samples and the annualeffective dose varied from 70.3 ± 13.5 to 100.8 ± 42.8 µSv with a mean of 87.5 ± 18.6 µSvy–1. The annual effective dose is higher than the world average.

Indoor radon measurements were carried out in 30 elementary schools in Tunis, the capitalcity of Tunisia, during the winter months of December 2008 to early March 2009. Twoclassrooms, one each from ground floor and first floor were chosen from each school makinga total of 60 classrooms. In some of the classrooms, two detectors (open and closed) wereused to measure the concentrations of radon as well as radon and its progeny to allow thecalculations of the equilibrium factors. Nuclear track detectors type LR-115 (Kodalpha)were used for the measurements. The results show that the radon concentration levels arelow in the range of 6–169 Bq m-3 with a mean value of 26.9 Bq m-3.The annual effective dose was found to vary between 0.025–0.715 mSv y-1 forteachers while the range for pupils was from 0.019–0.525 mSv y-1. These valuesare within the ICPR recommended values.

The activity concentrations of potassium, uranium and thorium in minerals and soilsamples from a mining site in Ibadan, Southwestern Nigeria were measured using gamma rayspectroscopy method. Effective dose per annum has been calculated from the activityconcentrations of dominant gamma-emitting natural radionuclides, potassium, uranium andthorium. Samples collected include minerals (beryl, quartz and feldspar), soil samplesfrom the mining pits, heaps and undisturbed land around the mining site. The activityconcentrations of 40K, 238U and 232Th, respectively in Bqkg-1 in the mineral samples were as follows: 1985 ± 16, 4.8 ± 0.9 and 11.8 ±5.8 for beryl sample, 115.1 ± 27.9, 5.0 ± 1.3 and 6.3 ± 5.0 for feldspar samples and 1421± 122, <4.8 and 20.1 ± 3.5 for quartz samples. For the soil samples, the meanactivity concentrations of 40K, 238U and 232Th,respectively, were 314.2 ± 5.7, 27.7 ± 2.6 and 11.5 ± 5.9 Bq kg-1 for soilsamples from the pits and 278.1 ± 5.4, 21.1 ± 2.0 and 15.3 ± 7.5 Bq kg-1 forsoil samples from heaps. The mean activity concentrations of soil samples from theundisturbed land around the mining site were 194.3 ± 25.2, 14.5 ± 5.1 and 13.3 ± 5.9 Bqkg-1 for 40K, 238U and 232Th, respectively.The effective dose to which the miners are exposed according to exposure scenarios werecalculated as 89.9 μSv y-1 for digging and handling of soil and mineral samplesin the pit and 63.6 μSv y-1 for handling of soil and mineral samples at theheaps.

La conversion en dose d’une exposition au radon fait l’objet de débats. L’UNSCEAR a défini un coefficient de conversion de la concentration en radon vers la dose efficace à partir de modèles dosimétriques et d’informations épidémiologiques. La CIPR recommande d’évaluer le risque lié au radon à partir des études épidémiologiques. Pour permettre la prise en compte d’une exposition combinée à d’autres sources de rayonnements ionisants, elle a adopté des conventions de conversion en dose efficace inférieures de 10 à 30 % au coefficient de l’UNSCEAR, sur la base du suivi épidémiologique des mineurs d’uranium. Ainsi, des niveaux de référence différents pour la concentration en radon peuvent être déduits d’un même niveau de dose efficace suivant que l’on applique l’un ou l’autre facteur de conversion. Cependant, il convient de rappeler que ces différences sont négligeables par rapport aux incertitudes associées aux études tant dosimétriques qu’épidémiologiques et que les niveaux de référence ne sont que des outils pour aider à réduire aussi bas que raisonnablement possible l’exposition au radon et le risque qui en résulte.

The individual monitoring of the occupational exposure in interventional radiology is problematic, owing primarily to the fact that the personnel has to wear a lead rubber protective apron. Indeed the dosimeter readings are not, in principle, accurately representative for the effective dose in all working conditions, irrespective of the over or under-apron dosimeter location. Therefore different simulations for this kind of exposure have been performed, which assess the effective dose from the doses to tissues and derive its relationship with the monitor readings. After briefly enquiring into the general approach to the effective dose estimate in the actual practice, the present paper firstly describes in this connection the characteristics of the radiation striking the staff in interventional radiology. Then it provides, within a unified framework and through a uniform notation, a review of the literature on the effective dose assessment from the doses to tissues relatively to this type of exposure. Specific results of a certain operative relevance are examined in some detail and particular attention is devoted to identify the most appropriate method for the effective dose estimate from the dosimeter readings. Which method is finally properly modified to conform it to the forthcoming update of the effective dose definition.

Les valeurs limites annuelles d’exposition de l’organisme entier des travailleurs et du public sont définies à l’aide de la dose efficace E. Les dosimètres individuels portés par les travailleurs évaluent un estimateur de cette grandeur de protection : l’équivalent de dose individuel. Cet article présente les deux méthodes de calcul des équivalents de dose et de la dose efficace ainsi que les résultats obtenus dans un champ mixte neutronique-photonique auprès d’une boîte à gants. Les équivalents de dose calculés pour ce poste de travail dépendent des hypothèses de calcul. Estimer la dose efficace à partir de ces résultats se révèle de ce fait délicat. Cette étude démontre ainsi l’intérêt de disposer d’un moyen de mesure de la dose efficace.

La grandeur dose efficace peut elle aussi fournir une contribution utile au processus d'optimisation des doses patients pour la radiologie vasculaire et la cardiologie. Pour la détermination de la dose efficace à l’aide de MCNP ou de MCNP-X, des différents fantômes anthropomorphes disponibles sont comparés. Afin de valider les simulations sur ordinateur, on effectue également des mesures de la dose efficace à l'aide d’un fantôme Rando-Alderson. Des différentes doses aux organes par produit dose-surface (PDS) sont calculées pour l'abdomen PA d’un champ de rayonnement et d’un spectre de 75 kVp et de 6,5 mm Al + 0,1 mm Cu pour 4 fantômes différents : (1) le fantôme mathématique BODYBUILDER ; (2) le fantôme voxelisé MAX ; (3) le modèle voxelisé du fantôme RA ; (4) le fantôme expérimental RA. À partir de ces doses aux organes une dose efficace par PDS est obtenu de respectivement 0,151 mSv/Gy cm2 ; 0,141 mSv/Gy cm2 ; 0,295 mSv/Gy cm2 et de 0,245 mSv/Gy cm2 pour les 4 fantômes susmentionnés. On note de grandes différences pour ce qui est des doses aux organes entre les fantômes mathématiques couramment utilisés dans le passé, et les modèles voxelisés de plus en plus utilisés. La différence pour le facteur global de conversion pour la dose efficace est plus faible. Les doses pour le fantôme RA (mesurées et calculées) sont systématiquement supérieures à celles de BODYBUILDER et de MAX.

A low cost in-situ gamma-ray spectrometric method for rapid assessment of radiation exposure, identification of radionuclides and detection of changes in environmental radioactivity has been employed in the determination of the natural gamma radiation dose levels in six major cities of the southeastern region of Nigeria. The soil radioactivity concentrations of the primordial radionuclides; 40K, 238U and 232Th were determined and have been related to the γ-dose rates in the cities. The activity concentration of 40K across the region ranged between 0.021 and 0.200 kBq kg–1; 238U was between 0.001 and 0.066 kBq kg–1 while that of 232Th ranged between 0.015 and 0.103 kBq kg–1. The total γ-absorbed dose rates in air in the region ranged between 0.016 and 0.090 μGy h–1 with a mean of 0.039 ± 0.018 μGy h–1. The mean of the annual outdoor effective dose due to the terrestrial gamma radiation for the region was calculated as 50 μSv y–1 representing 66% of the world average value.