An evaluation of theories concerning the health effects of low-dose radiation exposures

The danger of high, acute doses of radiation is well documented, but the effects of low-dose radiation below 100 mSv is still heavily debated. Four theories concerning the effects of lowdose radiation are presented here: supra-linearity, linear-no-threshold (LNT), threshold, and hormesis. The available evidence for and against these theories, which falls into the categories of either epidemiological studies, in vitro cell experiments, or in vivo animal experiments, includes studies which support each of the four theories. Currently, all radiation risk estimates are based on an LNT interpretation of the life span study (LSS) of atomic bomb survivors in Japan. However, while this pattern is undisputed at high doses, this linear extrapolation of risk to low doses is challenged by many recent experiments involving cell mechanisms and animal models, and there is also high uncertainty involved in estimating risk using only epidemiological studies.. Variations have also been observed depending on dose-rate, the organ at risk, and other factors for which the current data cannot adequately account. While the evidence is still inconclusive, the existence of a threshold in human responses to low-dose radiation would drastically alter current guidelines, such as those currently restricting many people from returning to their hometowna in Fukushima, Japan. Thus, it is important to further investigate these low*dose responses in order to more fully describe the risks and to create more accurate radiation guidelines.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2012

Author dc:creator

• Wei, Elizabeth J. (Elizabeth Jay)

Advisor dc:contributor.advisor

• Michael Golay.

• Nuclear Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/76961

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/76961