Radiation hormesis

Radiation hormesis is the hypothesis that low doses of ionizing radiation (within the region of and just above natural background levels) are beneficial, stimulating the activation of repair mechanisms that protect against disease, that are not activated in absence of ionizing radiation. The reserve repair mechanisms are hypothesized to be sufficiently effective when stimulated as to not only cancel the detrimental effects of ionizing radiation but also inhibit disease not related to radiation exposure (see hormesis). It has been a mainstream concept since at least 2009. While the effects of high and acute doses of ionising radiation are easily observed and understood in humans (e.g. Japanese atomic bomb survivors), the effects of low-level radiation are very difficult to observe and highly controversial. This is because the baseline cancer rate is already very high and the risk of developing cancer fluctuates 40% because of individual life style and environmental effects, obscuring the subtle effects of low-level radiation. An acute effective dose of 100 millisieverts may increase cancer risk by ~0.8%. However, children are particularly sensitive to radioactivity, with childhood leukemias and other cancers increasing even within natural and man-made background radiation levels (under 4 mSv cumulative with 1 mSv being an average annual dose from terrestrial and cosmic radiation, excluding radon which primarily doses the lung). There is limited evidence that exposures around this dose level will cause negative subclinical health impacts to neural development. Students born in regions of higher Chernobyl fallout performed worse in secondary school, particularly in mathematics. “Damage is accentuated within families (i.e., siblings comparison) and among children born to parents with low education..." who often don't have the resources to overcome this additional health challenge. Hormesis remains largely unknown to the public.

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés (8)

Cours associés (16)

Séances de cours associées (145)

MOOCs associés (1)

Radiation hormesis

Radiation-induced cancer

Exposure to ionizing radiation is known to increase the future incidence of cancer, particularly leukemia. The mechanism by which this occurs is well understood, but quantitative models predicting the level of risk remain controversial. The most widely accepted model posits that the incidence of cancers due to ionizing radiation increases linearly with effective radiation dose at a rate of 5.5% per sievert; if correct, natural background radiation is the most hazardous source of radiation to general public health, followed by medical imaging as a close second.

Linéaire sans seuil

Le modèle linéaire sans seuil (LSS, ou LNT en anglais) est un modèle utilisé en radioprotection pour fixer la limite réglementaire des expositions admissibles. Le modèle se fonde sur le principe que toutes les doses reçues sont équivalentes, indépendamment du débit de dose ou de leur fractionnement. De ce fait, les doses successives reçues dans une année ou au cours d'une vie peuvent être additionnées. Ce modèle conduit naturellement au principe ALARA (As Low As Reasonably Achievable, aussi faible que raisonnablement atteignable), minimisant les doses reçues par un individu.

Analyse du cycle de vie environmental

MOOC introduction à la pensée du cycle de vie et aux concepts théoriques pour réaliser et critiquer une analyse du cycle de vie.

EE-345: Radiation and antennas

Les antennes sont utilisées dans une multitude d'applications de communications et de détection, demandant des fréquences et propriétés d'antennes très différentes. Ce cours décrit la théorie de base

PHYS-450: Radiation biology, protection and applications

This is an introductory course in radiation physics that aims at providing students with foundation in radiation protection and with information about the main applications of radioactive sources/subs

PHYS-455: Introduction to medical radiation physics

This course covers the physical principles underlying medical diagnostic imaging (radiography, fluoroscopy, CT, SPECT, PET, MRI), radiation therapy and radiopharmacy. The focus is not only on risk an

Antennes : Ouvertures et rayonnements EE-345: Radiation and antennas

Explore les antennes avec des ouvertures, des problèmes équivalents et des schémas de rayonnement à partir de fentes minces.

Spectromètres et interféromètres CH-360: Atoms and radiation

Explore la mesure de la longueur d'onde à l'aide de spectromètres et d'interféromètres, en mettant l'accent sur la résolution et le pouvoir de résolution.

Protection contre les rayonnements : interactions et blindage PHYS-450: Radiation biology, protection and applications

Couvre les bases de la radioprotection, y compris les interactions avec la matière, les concepts de dose et les techniques de blindage.