Health Risks of Ionizing Radiation: - Clark University
Health Risks of Ionizing Radiation: - Clark University
Health Risks of Ionizing Radiation: - Clark University
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Glossary 209<br />
Thyroid Disease: disease occurring in the thyroid, a hormonal secretion gland in the neck, anterior to<br />
and partially surrounding the thyroid cartilage and upper rings <strong>of</strong> the trachea. Hypothyroidism is an<br />
example <strong>of</strong> a thyroid disease, resulting in inadequate levels <strong>of</strong> thyroid hormones in the body.<br />
Thyroiditis: Inflammation <strong>of</strong> the thyroid gland.<br />
Thyrotoxicosis: A condition resulting from exposure <strong>of</strong> body tissues to excessive levels <strong>of</strong> thyroid<br />
hormones. This may be caused by an overactive or damaged thyroid gland or by the administration <strong>of</strong><br />
excessive doses <strong>of</strong> thyroid hormone<br />
Total Effective Dose Equivalent: The sum <strong>of</strong> the effective dose equivalent from external exposure and<br />
the 50-year committed effective dose equivalent from internal exposure.<br />
Translocation: The alteration <strong>of</strong> a chromosome by transfer <strong>of</strong> a portion <strong>of</strong> it either to another<br />
chromosome or to another portion <strong>of</strong> the same chromosome.<br />
United Nations Scientific Committee on the Effects <strong>of</strong> Atomic <strong>Radiation</strong> (UNSCEAR): a committee<br />
established by the United Nations to study the effects <strong>of</strong> radiation to evaluate risk and create safety<br />
standards.<br />
Uranium: A naturally occurring material used for nuclear technology. There are a variety <strong>of</strong> uranium<br />
isotopes that include uranium-235 (which decomposes over millions <strong>of</strong> years) and uranium-238<br />
(which decomposes over billions <strong>of</strong> years).<br />
Working Level (WL): Any combination <strong>of</strong> short-lived radon daughters in 1 liter <strong>of</strong> air that will result in<br />
the ultimate emission <strong>of</strong> 1.30×10 5 MeV <strong>of</strong> potential alpha particle energy. For 220 Rn Daughters: The<br />
nuclides 216 Po, 212 Pb, 212 Bi, and 212 Po. For 222 Rn Daughters: The nuclides 218 Po, 214 Pb, 214 Bi, and 214 Po.<br />
Working Level Month (WLM): An exposure to 1 working level for 170 hours. This duration is derived<br />
from taking 2,000 working hours per year, dividing by 12 months per year, and rounding to 170<br />
hours.<br />
X-rays: Penetrating electromagnetic radiation (photon) having a wavelength that is much shorter than<br />
that <strong>of</strong> visible light. These rays are usually produced by excitation <strong>of</strong> the electron field around certain<br />
nuclei.<br />
Sources <strong>of</strong> Definitions:<br />
Low Dose <strong>Radiation</strong> Research Program, DOE. Glossary <strong>of</strong> Terms. Online at http://lowdose.org/pubs/<br />
glossary.html.<br />
The Why Files, <strong>University</strong> <strong>of</strong> Wisconsin. <strong>Radiation</strong> Reassessed, Glossary. Online at http://whyfiles.<br />
org/020radiation/glossary.html.<br />
Idaho State <strong>University</strong> Physics Department. <strong>Radiation</strong> Related Definitions. Online at http://www.<br />
physics.isu.edu/radinf/terms.htm#top.