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Chapter 13 Rad Safet
Question | Answer |
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Absorbed dose (D) | the amount of energy (x-rays) per unit mass absorbed by the irradiated tissue |
ALARA principle | a guiding philosophy that means “As Low As Reasonable Achievable” limited operators should always follow this philosophy when applying radiation to humans |
Biologic damage | the destructive interactions occur at the atomic level leading to cellular damage |
Chromosome | microscopic bodies that contain the genes |
Coulombs per kilogram (C/kg) SI (Systeme International) | SI unit for measuring radiation exposure in air |
DNA (deoxyribonucleic acid) | contains the coded information that the cell needs to function |
Dominant gene | genes that are chosen to make the offspring |
Effective dose (EfD) | this value is the limiting system used to calculate the upper limits of occupational exposure permissible |
Entrance skin exposure (ESE) | patient dose in radiography according to the exposure level at the skin mAs X D/mAs – mR (milliroengten) |
Enzyme | biologic chemicals that repair damage to cell membranes & DNA |
Erythema | a reddening of the skin, such as occurs after a large amount of radiation has been received (radiation burn) |
Free radical | temporary molecules and parts of molecules that occur as the result of ionization – may interact directly with DNA or may combine to produce toxic substances that are injurious to DNA |
Gene | determiners of heredity and are made of unique protein DNA |
Gonad | reproductive organs of humans |
Cataractogenesis | formation of cataracts |
Gonad shield | lead shields that is used for shielding of the reproductive organs |
Gray (Gy) | SI unit for absorbed dose; 1 Gy = 100 rad. The gray is determined by dividing the rad by 100 |
Ionizing radiation | radiation that when passing through the body tissues produce positively or negatively charged particles |
Mutation | changes to the genes of reproductive cells |
Carcinogenesis | increase risk of malignant disease part |
Nonstochastic | effects of radiation that can be related directly to the dose received, more severe with higher dose, has a threshold below which the effect will not occur |
Optically stimulated luminescence (OSL) | personnel monitoring device with use of aluminum oxide as a radiation detector |
radiation absorbed dose (RAD) | conventional unit measuring the quantity of radiation absorbed in the tissue |
Radiation protection | measures taken to safeguard patients, personnel, & the public from unnecessary exposure to ionizing radiation |
Recessive gene | genes that are not selected |
Rem | radiation equivalent to man |
Rem – (radiation equivalent to man) | unit of occupational exposure (conventional) |
Roentgen (R) | the conventional unit of measuring the amount of radiation in air, measured before it is absorbed in the body |
Sievert (Sv) | the SI unit of measuring the effective radiation dose to a man |
Source – skin distance (SSD) | the distance from the radiation source to the patient. Determined by measuring part thickness in inches and subtracting this measurement from SID |
Stochastic | effects that occur on a random basis with its effect being independent of the size of dose. The agent must be encountered during gestation period; not predictable; long term effects |
Thermo luminescent dosimeter (TLD) | personnel dose measuring device that gives off light when heated |
Teratogenic effects | effects from radiation that are in the offspring of the individual who received the agent, must be encountered during the gestation period |
Equivalent Dose (EqD) | the absorbed dose multiplied by the radiation weighting factor. |
Weighting (quality) factor | a number assigned to each type of radiation basedon the variation in biologic damage that is produced when individual receives exposure from a difference source |
Direct hit | breakage of DNA molecule as a result of an interaction with an x-ray photon |
Genetic effect | effects from radiation that are in the offspring of the individual who received the agent, must be encounter preconception |
Linear Energy Transfer (LET) | the rate at which energy is transferred from ionizing radiation to soft tissue, expressed in terms of kiloelectron volts per micrometer |
Relative Biologic Effectiveness (RBE) | a measure of the cell-killing ability of a particular radiation compared with that of 250 keV x-rays |
Threshold | the point at which a stimulus (x-ray) is great enough to produce an effect |
Nonthreshold | no point at which there is no risk of an effect |
Linear dose-response | the response to radiation is directly proportional to dose |
Nonlinear dose- response | the observed effects of radiation exposure in relation to the radiation dose given |
Indirect hit | causes a chemical reaction in the water that makes up most of the cells substance creating a free radical |