A patient treated with 3.7 GBq of I-131 after thyroidectomy for a papillary carcinoma presented, three days after iodine administration, an unusually elevated dose rate at 1 m. Scintigraphy and Single Photon Emission Computed Tomography coupled with Computed Tomography (SPECT/CT) were performed and showed a significant iodine uptake at the anterior mediastinal level due to the presence of a residual intrathoracic goitre. The proximity between this iodofixant goitre and the surrounding tissues prompted dose estimations to local organs at risk, in particular the heart. Dosimetric estimations were initially performed with OLINDA/EXM software, commonly used in nuclear medicine. More personalised doses were then calculated using the OEDIPE software associated with the Monte Carlo code MCNPX. Calculations with the OLINDA/EXM software enabled a first assessment of the mean absorbed dose to the heart, estimated at about 2 Gy for an uptake of 56% of the administered activity. In a second step, the use of the OEDIPE software allowed us to take into account the specific geometry of the patient as well as the distribution of iodine uptake at a mediastinal level and to determine a mean absorbed dose of approximately 1 Gy to the heart. Thus, the use of a voxelised phantom based on CT images of the patient, associated with direct Monte Carlo calculations, enabled us to improve the calculation of the absorbed doses to the heart compared with the use of a standard anthropomorphic phantom.

The objective of this study was to propose diagnostic reference levels (DRLs) for coronary computed tomography angiography (CCTA), in the context of a large variability in patient radiation dose, and the lack of European recommendations. Volume Computed Tomography Dose Index (CTDIvol) and dose-length product (DLP) were collected from 460 CCTAs performed over a 3-month period at eight French hospitals. CCTAs (∼50 per centre) were performed using the routine protocols of the centres, and 64- to 320-detector CT scanners. ECG gating was prospective (n = 199) or retrospective (n = 261). The large gap in dose between these two modes required to propose specific DRLs: 26 and 44 mGy for CTDIvol, and 370 and 970 mGy cm for DLP, respectively. This study confirms the large variability in patient doses during CCTA and underlines the need for the optimisation of cardiac acquisition protocols. Availability of national DRLs should be mandatory in this setting.

In August 2013, the French nuclear safety agency (ASN) requested the permanent group of experts in radiation protection in medicine (GPMED) to propose recommendations on the implementation of new technology and techniques in radiation oncology. These recommendations were finalized in February 2015 by the GPMED. In April 2015, the ASN sent a letter to the French ministry of health (DGS/DGOS), and its national health agencies (ANSM, INCa, HAS). In these letters, ASN proposed that, from the 12 recommendations made by the GPMED, an action plan should be established, whose control could be assigned to the French national cancer institute (INCa), as a pilot of the national committee for radiotherapy and that this proposal has to be considered at the next meeting of the national committee of radiotherapy. (C) 2015 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

Chez un patient ayant reçu 3,7 GBq d’131I après thyroïdectomie totale pour un carcinome papillaire, la mesure du débit de dose à 1 m, réalisée de façon systématique 3 jours après le traitement, a montré une valeur anormalement élevée. Une scintigraphie et une Tomographie d’Émission MonoPhotonique associée à une Tomodensitométrie (TEMP/TDM) ont alors été réalisées et ont montré une fixation importante de l’iode au niveau médiastinal antérieur due à la présence d’un goitre endothoracique résiduel. Compte tenu de la proximité entre ce goitre iodofixant et les tissus avoisinants, les doses reçues par les organes à risque les plus proches, notamment le cœur, ont été évaluées. Cette évaluation a été réalisée, dans un premier temps, avec le logiciel OLINDA/EXM, couramment utilisé en médecine nucléaire. Des doses plus personnalisées ont ensuite été calculées à l’aide du logiciel OEDIPE associé au code Monte Carlo MCNPX. Les calculs effectués avec le logiciel OLINDA/EXM ont permis d’évaluer la dose moyenne absorbée au cœur à environ 2 Gy avec une fixation de 56 % de l’activité administrée. Dans un second temps, l’utilisation du logiciel OEDIPE a permis de prendre en compte la géométrie spécifique du patient ainsi que la répartition de la fixation d’iode au niveau médiastinal et de déterminer une dose absorbée moyenne d’environ 1 Gy au cœur. Ainsi, l’utilisation d’un fantôme voxelisé, basé sur les images TDM du patient, associé à un calcul Monte Carlo direct a permis d’optimiser le calcul des doses absorbées au cœur par rapport à l’utilisation d’un fantôme anthropomorphe standard.

Interventional cardiology (IC) procedures can be responsible for relatively high radiation doses compared to conventional radiology especially for young patients. The aim of this study was to assess current exposure levels in a French reference centre of pediatric IC. Dosimetric data including dose area product (DAP), fluoroscopy time (FT) and number of cine frame (NF) were analysed taking into account patient weight. Doses to the lungs, esophagus, breast and thyroid were evaluated using anthropomorphic phantoms and thermoluminescent dosimeters. Finally, effective doses (E) were calculated using DAP and conversion factors calculated with PCXMC 2.0 software. 801 IC procedures performed between 2010 and 2011 were analysed. Large variations were observed for DAP, FT and NF values for a given procedure and a given weight group. The assessment of organ doses showed high levels of dose to the lungs and esophagus especially in new-born babies. For diagnostic procedures, E varied from 0.3 to 23 mSv with a mean value of 4.8 mSv and for therapeutic procedures, values ranged from 0.1 to 48.4 mSv with a mean value of 7.3 mSv. The highest values were recorded for angioplasty procedures (mean 13 mSv, range 0.6-48.4 mSv). The increasing use of IC in pediatric population stresses the need of setting up reference levels and keeping doses to children as low as possible.

Medical examination is the main source of artificial radiation exposure. Because children present an increased sensitivity to ionising radiation, radiology practices at a national level in paediatrics should be monitored.

This work suggests a classification of interventional radiology and cardiology procedures based on statistical analysis of operators’ finger doses measured in routine clinical conditions. In total, 346 finger doses were measured and the observed mean finger dose per class of procedure ranged from 0.03 mSv to 1.56 mSv for Cerebral, and Bone and Joint procedures, respectively. The statistical analysis showed that the finger dose in Cerebral procedures is significantly lower than in Cardiac procedures, which was significantly lower than the rest. Furthermore, finger doses in therapeutic procedures and in close ones were significantly greater than in diagnostic procedures and in distal ones. This work also studied the statistical relation between the use of ceiling-suspended shields or leaded gloves and the extremity dose. From the set of collected and analyzed data, a finger dose classification was proposed for different criteria: procedure type (diagnostics/therapeutic), proximity (close/distal), procedure class and access route.

Introduction Although interventional radiology (IR) is nowadays a widespread and well-known technique, it is associated to a potential deterministic risk for the patients, particularly for the most complex procedures (cardiology, neurology, vascular surgery). Since 2007, six patient overexposures declared to the French Authory (ASN) have needed a technical and radiobiological expertise from the Institut de radioprotection et de Sureté nucléaire (IRSN). Analysis of the recent patient overexposures in IR in France Although these incidents occurred in different fields (cardiology, neurology, vascular surgery), their analysis has shown some recurrent causes: –Lack of basic knowledge, within the interventionists, in the optimization capacity of their radiological equipments. –Poor awareness of the level of delivered dose and of potential for radiation injuries to patients. –No medical physicist involved in IR department. –Procedures (and doses) not optimized. –No alert values (DAP and fluoro time) for each different procedure. –No procedure for appropriate patient follow-up. Conclusion Lessons to be learned for the future ICRP published in 2000 its publication 85 dedicated to IR. Today, IR procedures are even more frequent and complex. Nevertheless, radiation protection (RP) principles are not enough implemented in the routine practice. To improve this situation, IRSN has published recommendations, among them: –Improve the education and training in RP of interventionists, especially those who have the weakest knowledge in RP, like cardiologists and surgeons. –Make sure that medical physicists are enlisted by the departments to take part in the optimization actions. –Require departments to assess their practice, through patient dose collection and establishment of local dose reference levels. –Establish alert values and patient follow up procedures. –Establish national dose reference levels for the most standardized procedures. –Harmonize units of DAP indicators between the different equipment manufacturers. The presentation will review the different actions in progress at national and European level to implement these recommendations.

The potential adverse effects associated with exposure to ionizing radiation from computed tomography (CT) in pediatrics must be characterized in relation to their expected clinical benefits. Additional epidemiological data are, however, still awaited for providing a lifelong overview of potential cancer risks. This paper gives predictions of potential lifetime risks of cancer incidence that would be induced by CT examinations during childhood in French routine practices in pediatrics. Organ doses were estimated from standard radiological protocols in 15 hospitals. Excess risks of leukemia, brain/central nervous system, breast and thyroid cancers were predicted from dose-response models estimated in the Japanese atomic bomb survivors' dataset and studies of medical exposures. Uncertainty in predictions was quantified using Monte Carlo simulations. This approach predicts that 100,000 skull/brain scans in 5-year-old children would result in eight (90 % uncertainty interval (UI) 1-55) brain/CNS cancers and four (90 % UI 1-14) cases of leukemia and that 100,000 chest scans would lead to 31 (90 % UI 9-101) thyroid cancers, 55 (90 % UI 20-158) breast cancers, and one (90 % UI <0.1-4) leukemia case (all in excess of risks without exposure). Compared to background risks, radiation-induced risks would be low for individuals throughout life, but relative risks would be highest in the first decades of life. Heterogeneity in the radiological protocols across the hospitals implies that 5-10 % of CT examinations would be related to risks 1.4-3.6 times higher than those for the median doses. Overall excess relative risks in exposed populations would be 1-10 % depending on the site of cancer and the duration of follow-up. The results emphasize the potential risks of cancer specifically from standard CT examinations in pediatrics and underline the necessity of optimization of radiological protocols.

Objectives Concerning Diagnostic reference levels (DRLs), IRSN's task is to analyse the data transmitted by the professionals of medical imaging, in order to update: the list of the relevant examinations, the dosimetric quantities and the numerical reference values. So, the collected data is representative of the national practices concerning the most common or radiation exposing examinations, taking into account technological developments and clinical practice. Materials and methods On the basis of the data collected between 2004 and 2008, the regulation was updated in 2011 (Decree of 24/ 10/2011). In 2009 and 2010 the dosimetric data analysis allows IRSN to strengthen and sometimes to complete the previous results, as well as to measure the evolution of: the regulation implementation, the clinical practices and the technologies implemented in conventional radiology, CT, and nuclear medicine. Results The DRL data transmission rate is heterogeneous and depends on the considered field of activity. With 67% of services having transmitted dosimetric evaluation in 2010, against 40% for CT and 20% for conventional radiology, nuclear medicine is the most assiduous. Nevertheless the annual periodicity is not followed by all services, regardless of the field of activity. For some exams, notable and recurring dosimetric differences between clinical practice and DRL are highlighted. On the other hand, it appears necessary that the DRL take into account new technologies affecting the delivered dose to the patient (CT of the PET-CT, iterative reconstruction in diagnostic CT) as well as the most radiation exposing procedures (diagnostic interventional radiology). Conclusions Following the analysis of data transmitted in 2009 and 2010, in addition to the update of the numerical values of the DRL for some examinations, the IRSN recommends to extend the scope of the NRD to the CT part of PET-CT examinations, even SPECT, and diagnostic interventional radiology. The reasons why, for certain exams, the average value is significantly higher than the DRL, with significant dispersion around this value, should also be investigated. Concerning Diagnostic reference levels (DRLs), IRSN's task is to analyse the data transmitted by the professionals of medical imaging, in order to update: the list of the relevant examinations, the dosimetric quantities and the numerical reference values. So, the collected data is representative of the national practices concerning the most common or radiation exposing examinations, taking into account technological developments and clinical practice. On the basis of the data collected between 2004 and 2008, the regulation was updated in 2011 (Decree of 24/ 10/2011). In 2009 and 2010 the dosimetric data analysis allows IRSN to strengthen and sometimes to complete the previous results, as well as to measure the evolution of: the regulation implementation, the clinical practices and the technologies implemented in conventional radiology, CT, and nuclear medicine. The DRL data transmission rate is heterogeneous and depends on the considered field of activity. With 67% of services having transmitted dosimetric evaluation in 2010, against 40% for CT and 20% for conventional radiology, nuclear medicine is the most assiduous. Nevertheless the annual periodicity is not followed by all services, regardless of the field of activity. For some exams, notable and recurring dosimetric differences between clinical practice and DRL are highlighted. On the other hand, it appears necessary that the DRL take into account new technologies affecting the delivered dose to the patient (CT of the PET-CT, iterative reconstruction in diagnostic CT) as well as the most radiation exposing procedures (diagnostic interventional radiology). Following the analysis of data transmitted in 2009 and 2010, in addition to the update of the numerical values of the DRL for some examinations, the IRSN recommends to extend the scope of the NRD to the CT part of PET-CT examinations, even SPECT, and diagnostic interventional radiology. The reasons why, for certain exams, the average value is significantly higher than the DRL, with significant dispersion around this value, should also be investigated.

BACKGROUND:Radiation can be used effectively for diagnosis and medical treatment, but it can also cause cancers later on. Children with congenital heart disease frequently undergo cardiac catheterization procedures for diagnostic or treatment purposes. Despite the clear clinical benefit to the patient, the complexity of these procedures may result in high cumulative radiation exposure. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study is being launched in France to evaluate the risks of leukaemia and solid cancers in this specific population. METHODS/DESIGN:The study population will include all children who have undergone at least one cardiac catheterization procedure since 2000 and were under 10 years old and permanent residents of France at the time of the procedure. Electronically stored patient records from the departments of paediatric cardiology of the French national network for complex congenital heart diseases (M3C) are being searched to identify the children to be included. The minimum dataset will comprise: identification of the subject (file number in the centre or department, full name, sex, date and place of birth), and characteristics of the intervention (date, underlying disease, type of procedure, technical details, such as fluoroscopy time and dose area product, (DAP), which are needed to reconstruct the doses received by each child). The cohort will be followed up through linkage with the two French paediatric cancer registries, which have recorded all cases of childhood leukaemia and solid cancers in France since 1990 and 2000, respectively. Radiation exposure will be estimated retrospectively for each child. 4500 children with catherizations between 2000 and 2011 have been already included in the cohort, and recruitment is ongoing at the national level. The study is expected to finally include a total of 8000 children. DISCUSSION:This French cohort study is specifically designed to provide further knowledge about the potential cancer risks associated with paediatric cardiac catheterization procedures. It will also provide new information on typical dose levels associated with these procedures in France. Finally, it should help improve awareness of the importance of radiation protection in these procedures.

Purpose: To improve cardiovascular dosimetry in radiation therapy (RT), as recommended in the NCRP report N°170, using hybrid computational phantoms (HCPs). Methods: For the Hodgkin lymphoma, HCPs were proposed as patient models to improve dose reconstructions for a multifactorial study on the coronary diseases following radiation therapy. HCPs were built using RT CT images and heart CT angiograms, merging the detailed heart morphology and the thoracic morphology at the treatment time. DICOM images generated from the HCPs were inserted into the treatment planning system. A personalized dose reconstruction is performed using the ballistics from the medical record. For the left-side breast cancer, different coronary topologies based on 22 heart CT angiograms were fitted into a representative thorax in terms of breast and heart volumes. Two treatments were simulated: BeamSet01 with tangential, tumoral bed and internal mammary chain (IMC) beams; BeamSet02 without IMC beams.For both studies, coronaries dose-volume histograms and dose statistics were collected. A 3D dose mapping displayed the coronary and aorta doses. Results: For the Hodgkin study, a dose was assessed for each coronary stenosis location.For the breast cancer study, the interventricular artery (IVA) topology differences induced a standard deviation for the IVA mean dose and the minimal dose received by 2% of the IVA volume of 35% and 76%, respectively, with BeamSet01 and 19% and 50%, respectively, with BeamSet02. CMI beams are responsible for the IVA highest doses. Conclusion: This work shows the potential of HCPs for research on radiation therapy and the necessity to know the precise topology of coronaries in retrospective studies and in clinical practice. For the Hodgkin study, a comparison with doses for patients without stenoses will be performed. For the left-side breast cancer study, other morphological parameters will be changed and errors in dose reconstructions with non-personalized anatomy will be assessed.

La validité de la théorie établie pour la méthode potentiostatique à double saut avec enregistrement chronocoulométrique a été vérifiée expérimentalement. A cet effect un appareillage a été construit et ses performances ont été analysées de manière systématique.L'étude cinétique du système U(V)/U(VI) en milieu carbonate conduit à des résultats expérimentaux en bon accord avec la théorie. Les faibles écarts observés sont interprétés en tenant compte de facteurs de second ordre agissant sur le transfert massique.Comme on peut s'y attendre les courbes de polarisation obtenues par polarographie directe et par les méthodes proposées sont totalement divergentes lorsque le dépolarisant engendré in situ diffère de l'espèce en équilibre avec la solution: il en est ainsi pour le système Cr(II)/Cr(III).The validity of the theoretical development established for the double-step potentiostatic method with chronocoulometric recording has been tested experimentally. The performance of an apparatus has been systematically studied.Experimental results are in good agreement with theory for the U(VI-U(V) system in carbonate media. The small deviations observed between theory and experiment are explained by second-order factors acting on the mass transfer.As can be expected, the polarization curves obtained by direct polarography and by the chronocoulometric method diverge completely when the depolarizer generated “in situ” is different from the species in equilibrium with the solution. Such a case is illustrated by the Cr(III)−Cr(II) system.

The morphological similarity of organs is studied with feature vectors based on geometric and Zernike 3D moments. It is particularly investigated if outliers and average models can be identified. For this purpose, the relative proximity to the mean feature vector is defined, principal coordinate and clustering analyses are also performed. To study the consistency and usefulness of this approach, 17 livers and 76 hearts voxel models from several sources are considered. In the liver case, models with similar morphological feature are identified. For the limited amount of studied cases, the liver of the ICRP male voxel model is identified as a better surrogate than the female one. For hearts, the clustering analysis shows that three heart shapes represent about 80% of the morphological variations. The relative proximity and clustering analysis rather consistently identify outliers and average models. For the two cases, identification of outliers and surrogate of average models is rather robust. However, deeper classification of morphological feature is subject to caution and can only be performed after cross analysis of at least two kinds of feature vectors. Finally, the Zernike moments contain all the information needed to re-construct the studied objects and thus appear as a promising tool to derive statistical organ shapes.

Follow-up of children exposed to ionising radiation from medical procedures. Given the increased radiosensitivity of children, our aim is to evaluate the risk of solid cancer and leukaemia associated with long-term medical exposure received during childhood. Two cohort studies were performed by the Laboratory of epidemiology, Institute of Radiation Protection and Nuclear Safety (IRSN). The first one, the "Cohort Child Seamier" includes all children born after 01/01/1995 and exposed to ionising radiation during medical scans performed between 2000 and 2013. The other one focuses on children exposed to ionising radiation during interventional cardiology procedures before the age of 10 years between 2000 and 2013. For each cohort, a retrospective assessment of individual exposure will be conducted by the Medical Radiation Protection Expertise Unit of the IRSN. A passive follow-up in terms of solid cancer and leukaemia will be carried out using data from paediatric cancer registries and from mortality data. The "Cohort Child Scanner" consists of over 80 000 children and is part of the European project EPI-CT, which will gather data from 9 national cohorts. The cohort of children in interventional cardiology will include more than 8 000 children. These cohort studies, with extended follow-up, will contribute to the assessment of the health impact of radiation exposure received during childhood.

As MOSFET (Metal Oxide Semiconductor Field Effect Transistor) detectors allow dose measurements in real time, the interest in these dosimeters is growing. The aim of this study was to investigate the dosimetric properties of commercially available TN-502RD-H MOSFET silicon detectors (Best Medical Canada, Ottawa, Canada) in order to use them for in vivo dosimetry in interventional radiology and for dose reconstruction in case of overexposure. Reproducibility of the measurements, dose rate dependence, and dose response of the MOSFET detectors have been studied with a Co-60 source. Influence of the dose rate, frequency, and pulse duration on MOSFET responses has also been studied in pulsed x-ray fields. Finally, in order to validate the integrated dose given by MOSFET detectors, MOSFETs and TLDs (7LiF:Mg,Cu,P) were fixed on an Alderson-Rando phantom in the conditions of an interventional neuroradiology procedure, and their responses have been compared. The results of this study show the suitability of MOSFET detectors for in vivo dosimetry in interventional radiology and for dose reconstruction in case of accident, provided a well-corrected energy dependence, a pulse duration equal to or higher than 10 ms, and an optimized contact between the detector and the skin of the patient are achieved. Health Phys. 104(4):379-384; 2013

L’intérêt des machines hybrides associant la tomographie à émission de positons (TEP) et l’imagerie par résonance magnétique (IRM), est de réaliser l’acquisition simultanée d’images métaboliques et moléculaires issues de la TEP, et d’images anatomiques et fonctionnelles issues de l’IRM. Pour parvenir à la mise au point de ces machines, il a fallu surmonter un certain nombre d’obstacles technologiques liés en premier lieu au mode de détection traditionnellement utilisé dans les machines TEP, celui-ci étant incompatible avec le champ magnétique de l’IRM. Le second défi technologique concerne la correction d’atténuation des images TEP à calculer à partir d’informations IRM, alors que celles-ci dépendent des propriétés magnétiques des tissus, sans relation directe avec leur coefficient d’atténuation. La TEP-IRM intégrée a de nombreuses applications, en particulier en imagerie cérébrale pour l’étude des maladies neurodégénératives. Cette technique donne accès à l’évaluation simultanée de biomarqueurs topographiques et physiopathologiques, augmentant ainsi les performances diagnostiques de chacune des deux modalités prise séparément. Elle permet de valider de manière croisée des techniques IRM avancées ou des traceurs TEP émergents dans le cadre du diagnostic de la maladie d’Alzheimer. Elle joue aussi un rôle capital pour une meilleure connaissance du fonctionnement cérébral normal et pathologique, basée sur les effets synergiques des deux techniques. Les machines hybrides TEP-IRM constituent une nouvelle modalité d’imagerie à part entière, ouvrant de nouveaux horizons pour l’étude des pathologies neurodégénératives, aussi bien en recherche qu’en pratique clinique.The interest of hybrid imaging systems combining positon emission tomography (PET) and magnetic resonance imaging (MRI) is to simultaneously acquire metabolic and molecular images from PET scans, and anatomical and functional images from MRI scans. In order to develop these systems, a number of technological obstacles had to be overcome, primarily related to the detection mode traditionally used in PET machines, which was incompatible with the magnetic field of MRI. The second technological challenge is the MR-based attenuation correction of PET images, when it depends on magnetic properties of tissues, without direct relation to their attenuation coefficient. Integrated PET-MRI has many applications, particularly in brain imaging for the study of neurodegenerative diseases. This technique provides access to simultaneous evaluation of topographical and pathophysiological biomarkers, thus increasing the diagnostic performance of each of the two modalities taken separately. It allows advanced MRI techniques or emerging PET tracers to be cross-validated in the diagnosis of Alzheimer's disease. It also plays a crucial role in a better knowledge of normal and pathological brain function, based on the synergistic effects of both techniques. Hybrid PET-MRI is a novel imaging modality in its own right, opening up new horizons for the study of neurodegenerative pathologies, both in research and in clinical practice.

Seven years after the publication of the first diagnostic reference levels (DRL) order, the analysis of the data allows the French Institute for radiation protection and nuclear safety (IRSN) to assess and evaluate the increase of the nuclear medicine departments involvement and of the level administered activities to the patients during the most common examinations performed in France. IRSN analyses show a good agreement between the distribution of transmitted examinations and the frequency of examinations performed in France, taking into account 95% of the number of examinations and 95% of the dose delivered to patients by nuclear medicine. These analyses highlight the necessary consistency between DRL regulation, the French society of nuclear medicine (SFMN) recommendations and national practice. The IRSN recommendations established from data analyses have leaded the authorities to publish a new DRL order in January 2012. This first update of the regulation takes into account actual clinical practice in nuclear medicine and introduces fundamental points as pediatric DRL. In the future, periodical updates will be implemented in order to take into account procedures and devices evolutions. (C) 2012 Elsevier Masson SAS. All rights reserved.