Adverse health effects of high levels of ionizing radiation exposure became apparent shortly after these initial discoveries. Roentgen’s discovery of X-rays resulted in the eventual invention of X-ray machines used to image structures in the human body and to treat health conditions. Thus, within a period of several years in the 1890s, man-made and naturally occurring radiation were discovered. Marie and Pierre Curie went on to purify radium from uranium ore in Becquerel’s laboratory, and in subsequent years, many other forms of radiation including neutrons, protons, and other particles were discovered. This turned out to be naturally occurring radiation emanating from the uranium. He concluded that the fogging was due to an invisible emission emanating from the uranium atoms and their decay products. The next major discovery occurred when Henri Becquerel noted that unexposed photographic plates stored in a drawer with uranium ore were fogged. The electrons produced by the electrical discharge had themselves produced another form of radiation, X-rays. Roentgen theorized that invisible emissions from the cathode-ray tube were causing the fluorescent screen to glow, and he termed these invisible emissions X-rays. Roentgen noted that when the electrons were being generated, a fluorescent screen on a nearby table began to glow. Why the committee has not accepted the view that low levels of radiation might be substantially more or less harmful than expected from the model used in this BEIR report, and What bodies of research the committee reviewed, Scenarios illustrating how people might be exposed to ionizing radiation above background levels,Įvidence for adverse health effects such as cancer and hereditary disease, The contribution of man-made radiation to public exposure, What is meant by low doses of ionizing radiation,Įxposure from natural “background” radiation, Health effects of concern include cancer, hereditary diseases, and other effects, such as heart disease. Examples of low-LET radiation, the subject of this report, include X-rays and γ-rays (gamma rays). Low-LET radiation deposits less energy in the cell along the radiation path and is considered less destructive per radiation track than high-LET radiation. This report, BEIR VII, focuses on the health effects of low levels of low linear energy transfer (LET) ionizing radiation. This report is the seventh in a series of publications from the National Academies concerning radiation health effects, referred to as the Biological Effects of Ionizing Radiation (BEIR) reports. Recently, data from atomic bomb survivors suggest that high doses are also connected to other health effects such as heart disease and stroke.īecause ionizing radiation is a threat to health, it has been studied extensively. Further, scientists have long known that in addition to cancer, ionizing radiation at high doses causes mental retardation in the children of mothers exposed to radiation during pregnancy. Specifically, substantial evidence exists that exposure to high levels of ionizing radiation can cause illness or death. These facts are just some of the many that make it difficult to characterize the effects of ionizing radiation at low levels.ĭespite these challenges, a great deal about this topic is well understood. Still another difficulty is that of distinguishing cancers that occur because of radiation exposure from cancers that occur due to other causes. One challenge to understanding the health effects of radiation is that there is no general property that makes the effects of man-made radiation different from those of naturally occurring radiation. Free electrons, in turn, can damage human cells. Ionizing radiation-the sort found in X-rays or gamma rays 1-is defined as radiation that has sufficient energy to displace electrons from molecules. The health effects of low levels of ionizing radiation are important to understand.
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