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 |
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Definition
| A classic method of displaying the sensitivity of a particular type of cell to radiation |
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Definition
| with a double-strand break in the same rung of the DNA ladder-like structure |
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Term
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Definition
| biologic damage occurs as a result of ionization of atoms on essential molecules produced by straight interaction with the incident radiation. |
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Term
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Definition
| is always a multistage process that first involves the production of free radicals that are created by the interaction of the radiation with water (H2O) molecules. These unstable agents, then, may proceed to interact with cellular molecules. They are so highly reactive that they have the capability to substantially disrupt master molecules, with resulting cell death. |
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Term
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Definition
| solitary atoms that behave as single entities and are very chemically reactive as a result of the presence of unpaired valence (outermost) electrons |
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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
| linear energy transfer (LET) |
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Definition
| The average energy deposited per unit length of track |
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Term
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Definition
| the loss or change of a base in the DNA chain |
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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 an oxygen-deprived environment to the radiation dose required to cause an identical response under normal oxygenated conditions. |
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Term
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Definition
| If ionizing radiation interacts with a DNA macromolecule, the energy transferred could rupture one of its chemical bonds and possibly sever one of the sugar–phosphate chain side rails, or strands, of the ladder-like molecular structure |
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Term
| radiation weighting factor (WR) |
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Definition
| is used to calculate the equivalent dose (EqD) to determine the ability of a dose of any kind of ionizing radiation to cause biologic damage. The WR values are similar to the values of RBE for any particular type of radiation. For example, the WR for x-radiation is 1, and the RBE for diagnostic x-rays is also 1. |
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Term
| relative biologic effectiveness (RBE) |
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Definition
| describes the relative capabilities of radiation with differing LETs to produce a particular biologic reaction. RBE of the type of radiation being used is the ratio of the dose of a reference radiation (conventionally 250-kVp 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 what 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 |
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Term
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Definition
| x-rays and gamma rays,can also be referred to as streams of particles called photons, each of which has no mass and no charge. |
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Term
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Definition
| occurs when a cell dies after one or more divisions. |
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Term
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Definition
| Exposing a cell to as little as 0.01 Gyt of ionizing radiation just before it begins dividing can cause mitotic delay |
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Term
| Indirect Action Characteristics |
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Definition
| when free radicals previously produced by the interaction of radiation with water molecules act on a molecule such as DNA, the damaging action of ionizing radiation is indirect in the sense that the radiation is not the immediate cause of injury to the macromolecule. The by-products of the radiation, the free radicals, are the immediate cause of this damage. |
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Term
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Definition
| often capable of reversing the damage from point lesion |
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Term
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Definition
| chemical unions created between atoms by the single sharing of one or more pairs of electrons. |
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