Documents dosimetry 31 results

A critical review of all data relevant to the assessment of human health effects associated with exposure to electromagnetic fields in the frequency range of 300 Hz to 300 GHz. Emphasis is placed on new data that shed light on the interactions of electromagnetic fields with biological systems and on the specific biological effects and responses that result. Over 500 recent studies were rigorously assessed. Sources of exposure considered include broadcasting systems, microwave ovens, induction heating stoves, visual display units, television receivers, dielectric heaters for industrial use, radar installations, and medical devices and procedures.

A chapter devoted to interaction mechanisms reviews the electrical properties of tissues and discusses direct and indirect interaction mechanisms, including the interaction of biological bodies with electrical charges induced on ungrounded or poorly grounded metallic objects such as cars, cranes, wires, and fences. A review of the large body of data from cellular and animal studies considers the strength of evidence pointing to effects on the nervous, endocrine, and immune systems, on reproduction, and on pre- and post-natal development. The report concludes that most of the biological effects of acute exposure are consistent with responses to induced heating. Data on human responses are assessed in the next chapter, which addresses concern about the effects of locally elevated temperatures resulting from the deposition of radiofrequency energy and the possible dangers, particularly for pregnancy outcome, linked to the use of visual display units. The report concludes that current data provide no clear evidence of detrimental health effects in humans exposed to radiofrequency fields. Other chapters provide guidelines for health hazard assessment and the development of protection standards and programmes.

"Crewmembers are exposed to galactic cosmic radiation on every flight and occasionally to solar protons on polar flights. Data are presented showing that the proton occasions are seven times more frequent than generally believed. Crewmembers are also exposed to neutrons and gamma rays from the sun and to gamma rays from terrestrial thunderstorms. Solar neutrons and gamma rays (1) expose the daylight side of Earth, (2) are most intense at lower latitudes, (3) may be as or more frequent than solar protons, and (4) have relativistic energies. The U.S. agency responsible for crewmember safety only considers the galactic component with respect to its recommended 20 mSv y(-1) limit, but it has an estimate for a thunderstorm dose of 30 mSv. In view of overlooked sources, possible over-limit doses, and lack of dosimetry, dose reconstructions are needed. However, using the agency dose estimates and the compensation procedure for U.S. nuclear weapon workers, the probability of crewmember cancers can be at least as likely as not. Ways to improve the quality of dose estimates are suggested, and a worker's compensation program specific to aviation crewmembers is recommended."

"The purpose of this article is to provide an overview and practical guide to occupational health professionals concerning the derivation and use of dose estimates in risk assessment for development of occupational exposure limits (OELs) for inhaled substances. Dosimetry is the study and practice of measuring or estimating the internal dose of a substance in individuals or a population. Dosimetry thus provides an essential link to understanding the relationship between an external exposure and a biological response. Use of dosimetry principles and tools can improve the accuracy of risk assessment, and reduce the uncertainty, by providing reliable estimates of the internal dose at the target tissue. This is accomplished through specific measurement data or predictive models, when available, or the use of basic dosimetry principles for broad classes of materials. Accurate dose estimation is essential not only for dose-response assessment, but also for interspecies extrapolation and for risk characterization at given exposures. Inhalation dosimetry is the focus of this paper since it is a major route of exposure in the workplace. Practical examples of dose estimation and OEL derivation are provided for inhaled gases and particulates."

"Réalisé par l'IRSN, ce rapport conclut à une baisse globale des expositions. La dose individuelle moyenne sur l'ensemble des effectifs surveillés est de 0,24 mSv en 2005. Sur les 273 886 travailleurs concernés par cette surveillance, 14 659 (5,4%) ont reçu des doses individuelles supérieures à 1 mSv, valeur qui correspond à la limite annuelle pour le public. 40 travailleurs (51 en 2004) ont reçu une dose supérieure à la limite réglementaire française fixée à 20 mSv par an et, parmi ceux-ci, 7 (13 en 2004) ont été exposés à une dose supérieure à 50 mSv."

"Cet article présente les premières réflexions du Groupe de travail, créé en septembre 2001 par la Société française de radioprotection (SFRP) sur des questions clés qui seront abordées par la Commission internationale de radioprotection (CIPR) lors de l'élaboration de nouvelles recommandations sur la radioprotection. Le choix des sujets considérés résulte de l'analyse du memorandum de la CIPR, publié dans le Journal of Radiological Protection en juin 2001 et de l'expérience des membres du Groupe de travail. Ce sont :- des réflexions générales sur le nouveau système de protection proposé par la CIPR, - les dimensions individuelle et collective du risque radiologique, - la comparaison avec la gestion des risques chimiques, - la protection radiologique de l'environnement, - les unités dosimétriques."(Résumé des auteurs)