Purpose of the studyTo analyze the effects of external radiation exposure on mortality of French nuclear workers.MethodA cohort of 29,204 workers employed between 1950 and 1994 at the French Atomic Energy Commission (Commissariat a l'energie atomique : CEA) or at the General Company of Nuclear Fuel (Compagnie Generale des Matieres nucleires : COGEMA, now Areva NC) was followed up for an average of 17.8 years. Standardized Mortality Ratios (SMRs) were computed with reference to French mortality rates. Dose-effect relationships were analyzed through trend tests and Poisson regressions.ResultsThe mean exposure to X and gamma radiation was 8.3 mSv (16.9 mSv for exposed worker population). A total of 1,842 deaths occurred between 1968 and 1994, for 3,117 expected from the national mortality statistics. Among the 21 main cancer sites studied, a statistically significant excess was observed for skin melanoma, and an excess of borderline statistical significance was observed for multiple myeloma. A dose-effect relationship was observed for leukaemia after exclusion of chronic lymphoid leukaemia (CLL). The relative risk observed for non CLL leukaemia, n = 20, at 100 mSv was 2.2, CI90% = [1.2;3.31. Significant dose-effect relationships were also observed for causes of deaths associated with alcohol consumption : mouth and pharynx cancer, cirrhosis and alcoholic psychosis and external causes of death.ConclusionThe risk of leukaemia increases with increasing exposure to external radiation; this is consistent with published results on other nuclear workers cohorts.

Objective: To analyse the effect of external radiation exposure on the mortality of French nuclear workers. Methods: A cohort of 29 204 workers employed between 1950 and 1994 at the French Atomic Energy Commission (Commissariat à l'Energie Atomique (CEA)) or at the General Company of Nuclear Fuel (COmpagnie GEnérale des MAtières nucléaires (Cogema, now Areva NC)) was followed up for an average of 17.8 years. Standardised mortality ratios (SMRs) were computed with reference to French mortality rates. Dose-effect relationship were analysed through trend tests and Poisson regression, with linear and log-linear models. Results: The mean exposure to X and gamma radiation was 8.3 mSv (16.9 mSv for exposed worker population). A total of 1842 deaths occurred between 1968 and 1994. A healthy worker effect was observed, the number of deaths in the cohort being 59% of the number expected from national mortality statistics. Among the 21 main cancer sites studied, a statistically significant excess was observed only for skin melanoma, and an excess of borderline statistical significance was observed for multiple myeloma. A dose-effect relationship was observed for leukaemia after exclusion of chronic lymphoid leukaemia (CLL). The relative risk observed for non-CLL leukaemia, n = 20, was 4.1 per 100 mSv (90% CI 1.4 to 12.2), linear model and 2.2 per 100 mSv (90% CI 1.2 to 3.3), log-linear model. Significant dose-effect relationship were also observed for causes of deaths associated with alcohol consumption: mouth and pharynx cancer, cirrhosis and alcoholic psychosis and external causes of death. Conclusion: The risk of leukaemia increases with increasing exposure to external radiation; this is consistent with published results on other nuclear workers cohorts.

A 15-Country collaborative cohort study was conducted to provide direct estimates of cancer risk following protracted low doses of ionizing radiation. Analyses included 407,391 nuclear industry workers monitored individually for external radiation and 5.2 million person-years of follow-up. A significant association was seen between radiation dose and all-cause mortality [excess relative risk (ERR) 0.42 per Sv, 90% CI 0.07, 0.79; 18,993 deaths]. This was mainly attributable to a dose-related increase in all cancer mortality (ERR/Sv 0.97, 90% CI 0.28, 1.77; 5233 deaths). Among 31 specific types of malignancies studied, a significant association was found for lung cancer (ERR/Sv 1.86, 90% CI 0.49, 3.63; 1457 deaths) and a borderline significant (P = 0.06) association for multiple myeloma (ERR/Sv 6.15, 90% CI <0, 20.6; 83 deaths) and ill-defined and secondary cancers (ERR/Sv 1.96, 90% CI -0.26, 5.90; 328 deaths). Stratification on duration of employment had a large effect on the ERR/Sv, reflecting a strong healthy worker survivor effect in these cohorts. This is the largest analytical epidemiological study of the effects of low-dose protracted exposures to ionizing radiation to date. Further studies will be important to better assess the role of tobacco and other occupational exposures in our risk estimates.

Cet article a pour but de donner les éléments essentiels que tout praticien doit connaître pour répondre aux interrogations légitimes d’une femme enceinte exposée aux rayonnements ionisants.Il comporte une mise au point des connaissances actuelles sur les effets déterministes (décès prénatal, malformation, retard mental) et stochastiques (cancers et leucémies) des rayonnements ionisants sur l’embryon et le fœtus. Les effets dépendent du niveau d’exposition et du terme de la grossesse auquel elle se produit. Les niveaux d’exposition aux rayonnements ionisants liés à la réalisation des principaux examens d’imagerie sont rappelés. L’attitude pratique à adopter devant l’exposition accidentelle d’une femme enceinte qui ignorait son état est expliquée en se fondant sur les positions consensuelles des organismes internationaux. La protection légale de la femme enceinte travaillant sous les rayonnements ionisants est également exposée.Dans la très grande majorité des cas, il est heureusement possible de rassurer la patiente tout en l’informant.The aim of this article is to give the essential elements that any practitioner must know to answer the legitimate questions of a pregnant woman exposed to ionizing radiation.It includes a development of current knowledge on the deterministic (prenatal death, organ malformation, mental retardation) and stochastic (cancer and leukemia) effects of ionizing radiation on the embryo and the fetus. These effects depend on the radiation dose to the conceptus and the stage of the pregnancy at which the exposure occurs. Levels of exposure to ionizing radiation associated with major imaging exams are recalled. The practical attitude adopted in front of accidental exposure of a pregnant woman who was unaware of her condition is explained based on consensus positions of international organizations. The legal protection of the pregnant woman working under ionizing radiation is also exposed.In the vast majority of cases, it is fortunately possible to reassure pregnant women while informing.

A study of dosimetric errors is under way within an international collaborative study of cancer risk among workers in the nuclear industry. The objective is to quantify errors in the estimated photon doses to individual organs used for cancer risk estimation. One source of errors is the response of old dosemeters in workplace exposure conditions. As these conditions are not well known, the International Study must rely on expert estimations. This paper describes a method to assess the proportion of the dose from photons in three energy ranges (< 100, 100-300, > or = 300 keV) using the responses under filters of a multi-element dosemeter. The method was tested on experimental and simulated data and provides a good estimate of the proportion of dose from photons below 100 keV, the most critical for dosemeter response. It was applied to personnel readings in one facility, confirming the experts' estimation. Beyond the International Study, the method has implication for the monitoring and protection of workers.

Proper recording of radiation doses is an essential part of the process of individual monitoring and shares the same objective. A dose record keeping system is more than just a computer based data storage system and should rather be a Dose Registration and Information System (DRIS). Objectives of dose record keeping are given. As a result of the integration of member states of the European Communities, cooperation and exchange of personnel between countries will be increasing. This will probably require national dose registration systems and adequate data communication between them. These developments emphasise the necessity for international harmonisation of dose record keeping systems and categorisation of the data they contain. General characteristics and specific aspects of dose record keeping systems are dealt with. Attention is also given to some special applications of the information recorded such as the use of data of epidemiological studies and for quality control purposes.

In order to be able to evaluate the dose received by a person accidentally exposed to gamma radiation, a method based on observing changes induced in the intensity of the electon spin resonance (ESR) spectrum of irradiated fabrics has been developed. About ten different fabrics were studied: the fibers of three of these fabrics exhibited useful dosimetric properties (cotton, polypropylene, quartz based fibers). In order to minimize the effects of fiber anisotropy on the ESR spectra, a system was devised to rotate samples in the measurement cavity during the time in which the spectrum is recorded. The relation between the intensity of the ESR signal and the ionizing radiation dose is linear over a large dose range (up to a few kilograys). However, the existence of an intrinsic signal from the non irradiated fabric makes it difficult to determine low doses. The minimum dose threshold was raised by employing a special sample preparation technique. The effects of temperature on the ESR signal (thermal fading) from irradiated fabrics was also studied. These results should be considered in the general context of the dosimetry of ionizing radiations through the effects of such irradiations on organic materials. The main results obtained in this field and their usefulness are discussed.

Une installation de production de gammas de capture a été réalisée auprès du réacteur ISIS du Centre d'études de Saclay pour l'étalonnage des instruments de radioprotection à des énergies de photons comprises entre 1 et 10 MeV. Les caractéristiques de deux faisceaux obtenus à partir de cibles de titane et de nickel sont présentées. Leur énergie moyenne pondérée sur la fluence est respectivement de 5,14 et 6,26 MeV. Les débits de dose maximaux dans un fantôme d'eau à la puissance maximale de la pile sont de l'ordre de 200 mGy/h. La réponse de deux types de dosimètres individuels, un dosimètre photographique à écrans multiples et un dosimètre thermoluminescent, est donnée à titre d'exemple. Elle montre, dans le cas présent, qu'un dosimètre parfaitement étalonné aux gammas du 60Co peut sous-estimer la dose à 5 ou 6 MeV d'un facteur 2 à 5 ou la surestimer de 50 % suivant l'écran placé devant l'élément détecteur.

A facility generating capture gamma rays has been realized using the ISIS reactor of the Saclay research center; this facility is to be used to calibrate protection instruments at photon energies between 1 and 10 MeV. The characteristics of beams generated using titanium and nickel targets are presented. The fluence weighted mean energies of the two beams are respectively 5.14 and 6.26 MeV. The maximum dose rates in a water phanton at full reactor power are about 200 mGy/h. The responses of two types of individual dosemeter (thermoluminescent or multiple screen photographic dosemeters) are given as examples. The responses show that, in the case considered, a dosemeter that has been correctly calibrated with Co-60 gammas can underestimate doses due to a 5-6 MeV beam by a factor of 2 to 5 or can overestimate doses by as much as 50 % according to the filter placed in front of the detecting element.

A capture ? ray beam facility is described. The tests and calibrations performed on titanium and nickel target emitted ? rays are presented. This facility is aimed at the calibrations of radioprotection instruments according to the requirements of an ISO standard in preparation.

An operational quantity is a quantity which is valid in the majority of 'real' radiation protection situations, easily measurable and requiring the use of only simple materials. The choice of such a quantity is a compromise between various considerations; the characteristics of the radiation to which personnel risk being exposed is a factor meriting the utmost attention. The results experimentally obtained in various radiation fields are presented. Individual dosemeters were used to study photon radiation fields. Multisphere techniques and fission chambers were used to study neutron radiation fields in situ. Conclusions are drawn regarding main factors, upon which the choice of an operational quantity should be based, together with appropriate dosimetry systems.

Nous avons déterminé la réponse des émulsions Kodak NTA, type A, aux neutrons émis par des sources radioactives et mesuré l’importance du fading pour connaître leur limite d’utilisation pour la dosimétrie des neutrons auprès des accélérateurs.

Le problème de l’interprétation des données d’un dosimètre photographique à écrans multiples a fait l’objet de nombreux traitements qui sont passés en revue. La solution présentée ici fait intervenir un programme de recherche opérationnelle pour le choix d’une hypothèse concernant le rayonnement reçu. Cette méthode, particulièrement souple, permet de tenir compte de diverses particularités de la réponse des émulsions en fonction de l’énergie et de la dose. Il arrive, de ce fait, que l’on tire avantage de ce qui pouvait être considéré comme un inconvénient de ce type de dosimètre.