13 research outputs found
Change in the Gender Division of Domestic Work after Mummy or Daddy Took Leave: An Examination of Alternative Explanations
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Safeguarding pollinators and their values to human well-being
Wild and managed pollinators provide a wide range of benefits to society in terms of contributions to food security, farmer
and beekeeper livelihoods, social and cultural values, as well as the maintenance of wider biodiversity and ecosystem
stability. Pollinators face numerous threats, including changes in land-use and management intensity, climate change,
pesticides and genetically modified crops, pollinator management and pathogens, and invasive alien species. There are
well-documented declines in some wild and managed pollinators in several regions of the world. However, many effective
policy and management responses can be implemented to safeguard pollinators and sustain pollination services
Ăvaluation des doses d'irradiation aux organes en scanographie pĂ©diatrique
Purpose. To estimate radiation doses from routine pediatric CT scans (body) and to propose dose reduction protocols. Materiel and methods. Study performed with a phantom equivalent to the body of 5 year old child with evaluation of doses delivered to breast, gonads, bone marrow (sternum, T12) and thyroid for GT examinations of the chest, abdomen, pelvis and spine. Extrapolation is made to estimate the doses for 1 year old and 10 year old children. Finally, dose reduction protocols are evaluated. Results. CT of the chest delivers significant doses to breast tissue and bone marrow, CT of the abdomen and pelvis delivers significant doses to the ovaries and CT pf the spine delivers significant doses to thyroid and bone marrow. Optimization can be achieved without degradation of the image quality, by reducing Kv and mAs within reasonable limits. This study may be used in order to evaluate the doses delivered by multi-detector CT units. © Ăditions Françaises de Radiologie, 2005.Objectifs DĂ©terminer la dose organe dĂ©livrĂ©e pour les scanners pĂ©diatriques courants du tronc et proposer une rĂ©duction des doses. MatĂ©riel et mĂ©thode Une Ă©tude sur fantĂŽme correspondant au corps dâun enfant de 5 ans a Ă©tĂ© menĂ©e afin de mesurer la dose dĂ©livrĂ©e aux gonades, Ă la moelle osseuse (sternum T12) et Ă la thyroĂŻde pour les scanners thoraciques, abdominaux, du bassin et du rachis. On a tentĂ© dâoptimiser les doses en rĂ©duisant les paramĂštres. RĂ©sultats Les doses organes dĂ©livrĂ©es sont assez significatives pour un scanner thoracique, aux seins et aux sites hĂ©matopoĂŻĂ©tiques, la dose aux ovaires est importante pour les scanners abdomino-pelviens et le scanner du rachis est trĂšs irradiant pour la thyroĂŻde ainsi que pour la moelle rouge. Lâoptimisation peut se faire sans dĂ©gradation de la qualitĂ© de lâimage en diminuant KV et mAs dans des limites raisonnables. Cette Ă©tude doit servir de base Ă lâĂ©valuation des doses dĂ©livrĂ©es par les scanners nouvelle gĂ©nĂ©ration
Optimisation en scanographie pédiatrique
The Department of radiology of the Hospital Trousseau (Paris) and IRSN have initiated in 2007 a detailed analysis of doses delivered to children undergoing CT examinations. This study involved three types of CT examination (chest, abdomen + pelvis and petrosal bones) and three age groups (new born to 1 year, 4 to 6 years and 9 to 11 years). A first analysis of doses was realised on a six months period of activity at the end of 2006. It stated that the standardized protocols of the scanner, that satisfied the relevant dosimetric requirements, were regularly modified by the operator to acquire the CT slides: the practice among the department was heterogeneous and the mean values of DLP were systematically higher than those recommended. The whole staff of the department has been informed of these first results and made aware of optimization of delivered doses. The standardized protocols of the scanner have been optimized. A second analysis, similar to the first one, was conducted in 2008. It showed the harmonization of the practice among the department, a significant decrease in the mean DLP (-50% for chest CT) and the respect for the dosimetric requirements for the three examinations concerned. © EDP Sciences, 2010.En 2007, le service de radiologie de lâHĂŽpital Trousseau (Paris) et lâIRSN ont initiĂ© une analyse dĂ©taillĂ©e des doses dĂ©livrĂ©es lors dâexamens scanographiques chez lâenfant. Cette Ă©tude a portĂ© sur trois types dâexamen (thorax, abdomen-pelvis et rochers) et trois tranches dâĂąge (nouveau nĂ© Ă 1 an, 4 Ă 6 ans et 9 Ă 11 ans). Une premiĂšre analyse des doses a Ă©tĂ© rĂ©alisĂ©e a posteriori sur lâactivitĂ© du second semestre 2006. Elle a montrĂ© que les protocoles dâacquisition du scanner, qui satisfaisaient aux recommandations dosimĂ©triques en vigueur, Ă©taient mal respectĂ©s dans le service : les pratiques Ă©taient hĂ©tĂ©rogĂšnes et les valeurs moyennes de PDL supĂ©rieures aux recommandations. AprĂšs ces premiers rĂ©sultats, une action de sensibilisation Ă lâoptimisation des doses a Ă©tĂ© menĂ©e auprĂšs du personnel et les protocoles dâacquisition du scanner ont Ă©tĂ© optimisĂ©s. Lâanalyse dosimĂ©trique reprise en 2008 suivant le schĂ©ma de 2006 a montrĂ© une harmonisation des pratiques au sein du service, une diminution significative des PDL moyens (-50 % par exemple en scanographie thoracique) et le respect systĂ©matique des recommandations dosimĂ©triques pour les trois examens Ă©tudiĂ©s
L'exposition des patients en radiodiagnostic: Bilan de l'étude dosimétrique réalisée en 2001-2003 dans 24 services français de radiologie
International audienceWithin the frame work of implementation of Directive 97/43, a French dosimetry campaign in diagnostic radiology was carried out, from April 2001 to February 2003, under supervision of a steering Committee, involving representatives of scientific and professional societies, of the Directorate-General for Nuclear Safety and Radiation Protection (DGSNR) and experts of the Institute of Radiation Protection and Nuclear Safety (IRSN). The aim was to assess patient dose associated to the standardized radiology procedures recommended by the "SociĂ©tĂ© française de radiologie" and to determine national dose reference levels (DRL) in diagnostic radiology. On the basis of protocols and data sheets established by the "SociĂ©tĂ© française de physique mĂ©dicale" and the IRSN, measurements were performed by multidisciplinary team (radiologist, physicists and radiographer) in 24 volunteer centers. The treatment of measured and collected data was in charge of the IRSN. For each of the 8 examinations selected, (4 in Conventional Radiology (CR) and 4 in Computed Tomography (CT)), data and dose measurements were assessed for 20 adult patients in each center. In CR, the entrance surface dose for each exposure was measured on 1231 patients using thermoluminescent dosimeters. In CT, the weighted Computed Tomography Dose Index and the Dose-Length Product were calculated for 667 patients, on base of the procedure parameters and the scanner normalized dose index values. For each type of examination, mean dose values and third quartile values were determined: depending on the type of examination, the results are either similar or lower than 1996 European DRL. These results are analyzed according the dose influencing parameters. Despite the 24 involved hospitals were not randomly selected, this preliminary study emphasizes the feasibility and great interest of a larger campaign of measurements based on a precise statistical survey of radiological practices in order to determine French DRL and to facilitate their periodic review in a continuous process of unnecessary doses reduction. © 2004 EDP Sciences.Dans le cadre des travaux de transposition en droit français de la directive 97/43 Euratom relative Ă la radioprotection des patients, une campagne nationale de dosimĂ©trie en radiodiagnostic sâest dĂ©roulĂ©e entre avril 2001 et fĂ©vrier 2003, Ă lâinitiative conjointe des sociĂ©tĂ©s savantes et professionnelles, de la Direction gĂ©nĂ©rale de la SĂ»retĂ© nuclĂ©aire et de la radioprotection (DGSNR) et de lâInstitut de radioprotection et de sĂ»retĂ© nuclĂ©aire (IRSN). Son objectif Ă©tait dâassocier des niveaux de doses aux procĂ©dures radiologiques standardisĂ©es, Ă©laborĂ©es dans une Ă©tape prĂ©cĂ©dente par la SociĂ©tĂ© française de radiologie, et dâengager une premiĂšre Ă©tude pour la dĂ©termination de niveaux de rĂ©fĂ©rence diagnostiques (NRD) français. Sur la base de protocoles de mesures et de fiches dâinformations Ă©tablis par lâIRSN et la SociĂ©tĂ© française de physique mĂ©dicale, la campagne a reposĂ© sur des Ă©quipes pluridisciplinaires (radiologue, physicien, technicien), dans 24 services de radiologie volontaires. Son organisation pratique, la centralisation des donnĂ©es et le traitement des rĂ©sultats ont Ă©tĂ© assurĂ©s par lâIRSN. Pour les 8 examens sĂ©lectionnĂ©s (4 en radiologie classique et 4 en scanographie), dans chaque service, 20 sujets dâĂąge adulte et de morphologie moyenne devaient faire lâobjet dâune dosimĂ©trie. En radiologie classique, la dose Ă lâentrĂ©e a Ă©tĂ© mesurĂ©e par dosimĂštres thermoluminescents placĂ©s Ă la peau, pour 1231 patients. En scanographie lâindice de dose de scanographie pondĂ©rĂ© et le produit dose Ă longueur ont Ă©tĂ© dĂ©terminĂ©s pour 667 patients Ă partir des paramĂštres de lâexamen et des donnĂ©es de base du scanner. Pour chaque type dâexamen les valeurs moyennes de chacune de ces grandeurs ainsi que celles du 75e percentile ont Ă©tĂ© calculĂ©es. Pour la grande majoritĂ© des examens et des centres ayant participĂ© Ă lâĂ©tude, il apparaĂźt que ces valeurs se situent en dessous des NRD proposĂ©s par la Commission europĂ©enne en 1996. Ces rĂ©sultats, analysĂ©s en fonction des facteurs dâinfluence sur la dose et des limites mĂ©thodologiques de lâĂ©tude (volontariat des services participant), prouvent la faisabilitĂ© et le grand intĂ©rĂȘt dâune campagne nationale de mesures de doses en radiologie, Ă plus grande Ă©chelle, qui permettrait dâĂ©tablir des NRD spĂ©cifiques Ă la pratique française, de prĂ©voir leur rĂ©vision pĂ©riodique et de dĂ©finir les dĂ©marches dâoptimisation appropriĂ©es
Study of erodable paint properties involved in antifouling activity
To produce ecological marine paints, it is necessary to understand the phenomena involved in antifouling activity. Due to the multivariable components which have to be taken into account and due to their analytical intricacy, only studies based on selected properties are conceivable. In this study, four properties have been chosen, viz. erosion, biocide release, roughness and the physicochemical characteristics of the film surface. A principal-component analysis (PCA) of the experimental data has shown that, among the selected properties, only erosion affected antifouling efficiency. A more detailed investigation of erosion by quantifying global hydration and hydrolysis of immersed paints revealed the difficulty in linking the chemical structure of binders to the final erosion properties. Biocide release from paints, quantified by chromatographic methods coupled with UV detection, was inferior to the doses stated by the paint producers. These observations allowed the conceiving of formulations with reduced amounts of active molecules. The development of erodable, biodegradable binders associated with non toxic compounds is a promising way to obtain efficient antifouling paints compatible with existing, preventive systems
Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France
International audienceBackground Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk. Methods The cohort included 67 274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses. Results During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures. Conclusions This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans. © 2015 Cancer Research UK
Suivi dâenfants exposĂ©s aux rayonnements ionisants dans le cadre de procĂ©dures radiologiques Ă visĂ©e diagnostique
Compte tenu de la radiosensibilité accrue des enfants
aux rayonnements ionisants, notre objectif est dâĂ©valuer les risques
de cancers solides et de leucémies à long terme associés aux expositions
mĂ©dicales reçues pendant lâenfance. Deux Ă©tudes de cohorte sont
rĂ©alisĂ©es par le Laboratoire dâĂ©pidĂ©miologie de lâInstitut de radioprotection
et de sĂ»retĂ© nuclĂ©aire (IRSN). Lâune, la « Cohorte Enfant Scanner »
porte sur les enfants nés aprÚs le 01/01/1995 et exposés aux rayonnements
ionisants lors de scanners rĂ©alisĂ©s entre 2000 et 2013. Lâautre
porte sur les enfants exposés lors de procédures de cardiologie interventionnelle
avant lâĂąge de 10 ans entre 2000 et 2013. Pour chacune des cohortes,
une Ă©valuation rĂ©trospective individuelle de lâexposition sera rĂ©alisĂ©e
par lâUnitĂ© dâexpertise en radioprotection mĂ©dicale de lâIRSN. Un
suivi passif en termes de cancers solides et de leucémies sera réalisé
grùce aux données des registres de cancers pédiatriques et aux données
de mortalité. La « Cohorte Enfant Scanner » est constituée de plus
80 000 enfants et sâinscrit dans le projet europĂ©en EPI-CT, qui
regroupe 9 cohortes nationales. Ă terme, la cohorte des enfants
en cardiologie interventionnelle regroupera plus de 8 000 enfants.
Ces Ă©tudes de cohortes, avec un suivi prolongĂ©, permettront dâĂ©tudier
lâimpact sur la santĂ© des expositions radiologiques reçues pendant
lâenfance