- Industry: Government
- Number of terms: 33950
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United States Department of Health and Human Services, Radiation Emergency Medical Management
Any material in which neutrons can cause a fission reaction. The three primary fissile materials are uranium-233, uranium-235, and plutonium-239.
Industry:Medical devices
The splitting of a nucleus into at least two other nuclei that releases a large amount of energy. Two or three neutrons are usually released during this transformation. See also fusion.
Industry:Medical devices
A cytogenetic technique used to detect and localise the presence or absence of specific dna sequences on chromosomes.
Industry:Medical devices
Exposure to radiation that occurs in several small acute exposures, rather than continuously as in a chronic exposure.
Industry:Medical devices
A reaction in which two lighter nuclei unite to form a heavier one, releasing energy in the process. Reactions of this type are responsible for the release of energy in stars or in thermonuclear devices.
Industry:Medical devices
High-energy electromagnetic radiation emitted by certain radionuclides when their nuclei transition from a higher to a lower energy state. These rays have high energy and a short wave-length. All gamma rays emitted from a given isotope have the same energy, a characteristic that enables scientists to identify which gamma emitters are present in a sample. Gamma rays penetrate tissue farther than do beta or alpha particles but leave a lower concentration of ions in their path to potentially cause cell damage. Gamma rays are very similar to x-rays. See also neutron.
Industry:Medical devices
A radiation detection and measuring instrument consisting of a gas-filled tube containing electrodes, between which an electrical voltage but no current flows. When ionising radiation passes through the tube, a short, intense pulse of current passes from the negative electrode to the positive electrode and is measured or counted. The number of pulses per second measures the intensity of the radiation field. Geiger counters are the most commonly used portable radiation detection instruments.
Industry:Medical devices
Hereditary effects (mutations) that can be passed on through reproduction because of changes in sperm or ova. See also teratogenic effects, somatic effects.
Industry:Medical devices
The new international system (si) unit of radiation dose, expressed as absorbed energy per unit mass of tissue. The si unit "gray" has replaced the older "rad" designation. (1 gy = 1 joule/kilogram = 100 rad). grey can be used for any type of radiation (e.g., alpha, beta, neutron, gamma), but it does not describe the biological effects of different radiations. Biological effects of radiation are measured in units of "sievert" (or the older designation "rem"). Sievert is calculated as follows: grey multiplied by the "radiation weighting factor" (also known as the "quality factor") associated with a specific type of radiation.
Industry:Medical devices
The time any substance takes to decay by half of its original amount. See also biological half-life, decay constant, effective half-life, radioactive half-life.
Industry:Medical devices
