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Definition
| Radiation that produces positively and negatively charged particles (ions) when passing through matter |
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Term
| Linear energy transfer (LET) |
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Definition
| The average of energy deposited by ionizing radiation in an object per unit length of track as it passes through the object. It is expressed in units of keV/µm |
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Term
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Definition
| Short wavelength, high energy electromagnetic waves emitted by the nuclei of radioactive substances. Although they are generally shorter in wavelength than x-rays and have a different point of origin their other characteristics are identical to those of diagnostic x-rays |
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Term
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Definition
| A nonmitotic or nondivision form of cell death that occurs when cells die without attempting division during the interphase portion of the cell life cycle. Also known as programmed cell death (formerly called interphase death) |
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Term
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Definition
| A method of displaying the sensitivity of a particular type of cell to lethal effects of radiation. |
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Term
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Definition
| The breaking of one or both of the sugar–phosphate chains of a DNA ladder-like structure, which is a potential outcome when ionizing radiation interacts with a DNA macromolecule. |
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Term
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Definition
| Biologic damage that occurs as a result of ionization of atoms on essential molecules, which may cause these molecules to become either inactive or functionally altered. |
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Definition
| Solitary atoms, or most often a combination of atoms, that are very chemically reactive as a result of the presence of unpaired electrons. |
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Term
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Definition
| The effect produced by free radicals that are created by the interaction of radiation with water molecules; cell death can result. |
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Term
| law of Bergonié and Tribondeau |
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Definition
| The radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation. |
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Term
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Definition
| Changes in genes caused by the loss or change of a nitrogenous base on the DNA chain. It is generally the result of the interaction of high-energy radiation with a DNA molecule |
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Term
| oxygen enhancement ratio (OER) |
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Definition
| The ratio of the radiation dose required to cause a particular biologic response of cells or organisms in any oxygen-deprived environment to the radiation dose required to cause an identical response under normally oxygenated conditions. |
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Term
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Definition
| Altered areas in molecules caused by the breaking of a single chemical bond |
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Term
| radiation weighting factor (WR) |
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Definition
| A dimensionless factor (a multiplier) that was chosen for radiation protection purposes to account for differences in biologic impact among various types of ionizing radiations. This factor places risks associated with biologic effects on a common scale. |
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Term
| relative biologic effectiveness (RBE) |
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Definition
| Describes the relative capabilities of radiation with differing linear energy transfers (LETs) to produce a particular biologic reaction. Simply defined, it is the ratio of the dose of a reference radiation (conventionally, 250kVp x-rays) to the dose of radiation of the type in question that is necessary to produce the same biologic reaction in a given experiment. The reaction is produced by a dose of the test radiation delivered under the same conditions |
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Term
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Definition
| Concept of radiation damage resulting from discrete and random events. If a critical location on the master molecule (believed to be DNA) is a target receiving multiple hits from ionizing radiation, it may well be inactivated. Normal cell function will then cease, and the cell will die. If, on the other hand, it receives only a single hit, then the master molecule most likely will still be operational. The target theory concept may be useful for explaining cell death and nonfatal cell abnormalities caused by exposure to radiation. |
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Term
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Definition
| Electromagnetic radiation can travel and interact with matter in the form of a wave or a particle. For this reason, x-rays may be described as both waves and particles. |
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Term
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Definition
| Cell death that occurs when a cell dies after one or more divisions. This can happen after irradiation. Mitotic death is also known as genetic death |
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Term
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Definition
| The permanent loss of a cell's ability to divide because of exposure to doses of ionizing radiation in the range of 1 to 10 Gy. The cell itself does not die but continues to metabolize and synthesize nucleic acids and proteins. |
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Term
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Definition
| Ionization interaction of radiation with water molecules resulting in a separation into other components. |
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