CT scanning technology is a valuable tool to diagnose many diseases; however, the level of the radiation dose is a source of concern, especially for children. CT scan systems and dose measurement methods have evolved over the years; but reported pediatric effective doses (EDs) have sometimes exceeded the annual dose limit recommended by the ICRP (1 mSv per 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 in pediatric imaging from the early age of CT examinations until now. The first epidemiological results regarding the associated risk of cancer are also briefly presented.

This article proposes an assessment of the ingestion doses potentially received by people living in the Japanese areas most severely affected by the radioactive deposits due to the Fukushima nuclear accident. The assessment distinguishes two consecutive periods: the first 2 months (March 15th to May 15th 2011) and the rest of the year 2011, according to the two main foodstuff contamination periods identified (Renaud et al., 2013). On the basis of the worst-case hypothesis that can reasonably be made, the estimated doses are much lower than they might have been in other circumstances, on account of generally moderate levels of contamination for most foods, early evacuation of the most severely affected areas and the consumption bans ordered by the Japanese authorities. Thus, a single ingestion of 100 g of leafy vegetables in the early days by a one-year-old child living in non-evacuated localities near Iitate and Kawamata could have led to an equivalent dose to the thyroid of about 25 mSv; and to a thyroid dose of about 140 mSv for the rather unrealistic scenario of a daily consumption. Because of the rapid decrease in the contamination of vegetables and a much weaker contamination of other crops, and thanks to measures taken by the authorities (prohibition of consumption, use of certain fodder, etc.), the ingestion doses potentially received during the remainder of the year 2011 are estimated to be below 1 mSv. In the event that sales limits would have been ignored, only repeated consumption of mushrooms would have led to doses above that level. Even with the worst-case hypotheses, the doses potentially caused by ingestion are much lower than those resulting from outdoor exposure to radioactive deposits: approximately several millisieverts in a year for the population living in the non-evacuated localities near Iitate and Kawamata.

The term “dose constraint” has been used in radiological protection since 1990. Its practical application has varied from country to country to the present day. The authors of this paper believe that it is an underestimated tool for the purpose of radiological protection. This study aims to estimate local dose constraints for workers in conventional nuclear medicine and radiology departments, on the basis of doses received in the last 3 to 4 years by different groups of workers. The levels of exposure to employees of the nuclear medicine department correspond well to levels in other countries, but for employees belonging to the radiology department, the levels are significantly lower. Unification of the practical application of dose constraints and legislation concerning their specific values would increase the relevance and effectiveness of these operational units. This is a playing field for radiation safety officers for the determination and widespread publication of local dose constraints in their particular medical departments.

Transfer factors of 226Ra, 210Pb and 210Po from soil contaminated with naturally occurring radioactive materials (NORM) in oilfields to some grazing plants were determined using pot experiments. Contaminated soil was collected from a dry surface evaporation pit from a Syrian oilfield in the Der Ezzor area. Five types of plants (Atriplex halimus L., Atriplex canescens, Atriplex Leucoclada Bioss, Alfalfa and Bermuda grass) were grown and harvested three times over two years. The results show that the mean transfer factors of 226Ra from the contaminated soil to the studied plant species were 1.6 × 10-3 for Atriplex halimus L., 2.1 × 10-3 for Atriplex canescens, 2.5 × 10-3 for Atriplex Leucoclada Bioss, 8.2 × 10-3 for Bermuda grass, and the highest value was 1.7 × 10-2 for Alfalfa. Transfer factors of 210Pb and 210Po were higher than 226Ra TFs by one order of magnitude and reached 7 × 10-3, 1.1 × 10-2, 1.2 × 10-2, 3.2 × 10-2 and 2.5 × 10-2 for Atriplex halimus, Atriplex canescens, Atriplex Leucoclada Bioss, Bermuda grass and Alfalfa, respectively. The results can be considered as base values for transfer factors of 226Ra, 210Pb and 210Po in semiarid regions.

Objectif : comparer la dose délivrée aux patients et la qualité d’image en routine clinique lors de la réalisation d’un scanner abdominal ne disposant pas des techniques de reconstructions itératives (RI) par rapport à un examen réalisé sur un scanner disposant des RI. Matériels et méthodes : il s’agit d’une étude rétrospective incluant 30 patients ayant eu deux examens abdominaux sur un scanner 40 coupes (TDM40) et sur un scanner 256 coupes avec RI (TDM256). Les patients, suivis pour une pathologie abdominale chronique, ont eu un examen de même indication sur chaque scanner avec un protocole comprenant une phase abdomino-pelvienne au temps portal. La longueur d’acquisition, la dose efficace et le Produit Dose Longueur (PDL) ainsi que des évaluations quantitatives et qualitatives de l’image ont été comparés. Résultats : la dose efficace moyenne pour un examen était de 17,3 mSv avec le TDM40 (PDL : 1019 mGy.cm) contre 11,1 mSv avec le TDM256 (PDL : 654 mGy.cm) soit une réduction de 35,8 % (p < 0,001). Les longueurs d’acquisitions et l’évaluation quantitative étaient comparables dans les deux groupes. L’évaluation qualitative était légèrement supérieure sur le TDM40 mais aucun examen n’a été considéré comme sous-optimal. Conclusion : l’utilisation d’un scanner équipé de RI permet une réduction significative de la dose efficace tout en préservant une bonne qualité d’image.

In the last few years there has been significant development of radiation therapy (RT) equipment with advanced imaging and delivery techniques, as well as treatment planning systems. From this perspective, proactive approaches for risk assessment were identified as a powerful tool in modern radiation oncology. A multidisciplinary working group (WG) has been established in the framework of the Italian association for medical physics (AIFM) to promote the use of prospective approaches in the radiotherapy scientific community. This paper describes the main actions carried out by the WG in order to collect information about the engagement of Italian medical physicists in the risk management process, in reporting possible incidents in RT and in the procedures of collecting and analysing near misses. In particular, the main scope of the study was to evaluate the actual level of experience in use of proactive risk analysis tools in modern RT by medical physicists. Finally, the measures implemented by the WG in order to promote the use of such approaches, and consequently to contribute to enhancing safety and radiation protection culture in radiation oncology are described.

L’examen des résultats de mesure de 14C, notamment dans le cadre de la surveillance environnementale requiert la connaissance de certaines spécificités du comportement du carbone. Les principaux paramètres susceptibles d’influer sur les mécanismes d’incorporation du carbone dans les matrices environnementales et donc sur les niveaux mesurés en 14C sont succinctement rappelés. Des résultats de mesure d’échantillons biologiques ont été acquis par l’IRSN dans des zones non directement influencées par des rejets d’installations nucléaires; ces chroniques permettent de présenter les valeurs du bruit de fond naturel et rémanent, exprimé en activité spécifique (Bq 14C/kg C), hors de l’influence contemporaine d’un rejet local de 14C.

La scintillation liquide est une méthode d’analyse de choix du suivi radio toxicologique des travailleurs susceptibles d’être exposés à des sources émettrices β purs. Les éléments étant présents à l’état de traces dans les urines, il est nécessaire d’optimiser la technique de mesure afin d’obtenir la meilleure sensibilité. Ces dernières années ont vu apparaître des nouvelles générations de liquides scintillants, moins polluants et moins toxiques, destinés à remplacer les liquides scintillants traditionnels. Ces scintillants dits de « nouvelle génération » possèdent cependant un inconvénient technique à leur utilisation : une dissipation plus longue de l’énergie émise par le photon de fluorescence résultant de l’interaction entre le milieu scintillant et le rayonnement. Ce phénomène a un impact direct sur la qualité de la détection et amène à rechercher une valeur du Delay Before Burst optimale qui permette de distinguer les signaux du rayonnement de la source à mesurer, de ceux venant du milieu environnant. Cette étude vise à montrer l’importance du choix de la valeur du paramètre Delay Before Burst dans l’optimisation des limites de détection pour les mesures en scintillation liquide. L’influence de ce paramètre a été étudiée sur les différents radionucléides mesurés au Laboratoire d’Analyses Médicales Radiotoxicologiques (LAMR) de l’Institut de Radioprotection et de Sureté Nucléaire (IRSN); le 3H, le 14C et le 89Sr. Notre étude compare les rayonnements β mesurés avec un liquide scintillant traditionnel : le Pico-Fluor 40 et un liquide scintillant de nouvelle génération : l’Ultima Gold LTT.

The ASN launched in July 2007 a system of notification of significant events dealing with ionising radiation, called ESRs. The ESRs notified to the ASN in the medical field have been increasing since 2007 and amounted to a total of 2300. The information showed that the medical activities with the most important implications for radiation protection regarding professionals are interventional radiology, with dose limit overruns, brachytherapy and nuclear medicine, with internal contamination of operators. For patients, deterministic effects were observed in interventional radiology as well as large doses in nuclear medicine, when the process of issuing radiopharmaceuticals is not managed, with the worst ESR being a partial removal of the thyroid. Many events involve leaks of radioactive waste and emphasise the need to strengthen the maintenance and monitoring facilities, and can cause major disruptions of service with delays in the delivery of care. The feedback emphasises the importance of empowering medical physicists and radiation protection officers to implement steps of quality management and risk management as well as clinical audits.

Magnetophosphenes are described as flickering lights appearing in the visual field, due to retinal exposure to time-varying magnetic fields (MF). Human magnetophosphene perception (MP) serves as a scientific basis for international guidelines intending to limit exposure to electromagnetic fields in the extremely low frequency range. However, the flux density threshold at which MP occurs, as well as the dose and frequency responses of the phenomenon, are not clearly experimentally established. The 50–60 Hz threshold is extrapolated from data in the lower frequency range. The objective of this paper is to provide a descriptive anecdotal report of MP from 8 individuals exposed to 50 mT MF at 20, 50 and 60 Hz. They describe variations of flickering light perceptions in the visual field, matching the description by D’Arsonval (1896). This preliminary testing introduces a new experimental protocol, which will test the threshold for MP and other associated neurophysiological responses in humans.