Fundamental Research Division
Nuclear toxicology is the study of the adverse effects of radionuclides on health. Two aspects must be considered: radiotoxicity, i.e. the effect of ionizing radiation emitted by radionuclides; and the chemical toxicity of the element or compound in question.
Animal experimentation, and increasingly also in vitro models, makes it possible to acquire knowledge about the behavior and effects of radionuclides in the body. Extrapolation of these data to humans, and the epidemiological monitoring of populations occupationally or environmentally exposed, provides a better understanding of the health risks associated with exposure to ionizing radiation.
Radioactivity has been naturally present on Earth since its formation. Artificial radionuclides were much more recently introduced by humans. Some radioactive elements present in the environment today are both natural and artificial in origin (e.g. carbon-14 and tritium).
Several types of exposure to radioactive compounds exist. A distinction is made between radioactive contamination and exposure to ionizing radiation.
The path of entry and chemical characteristics of an element influence its behavior in the human body and the biological consequences of internal contamination.
The effects of toxic nuclear agents on health can be of two different types: radiological or chemical. Within each category, one can distinguish deterministic effects (i.e. threshold effects) from random or stochastic effects (i.e. effects considered without threshold).
Deterministic effects appear beyond a dose threshold, and the severity of radiation-induced effects increases proportionally with the dose.
Random or stochastic effects do not appear after a dose threshold; the frequency of effects increase with the dose, but not the severity.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.