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RADT456 Rad Protect.
ARRT registry review covering Radiation Protection
| Question | Answer |
|---|---|
| Velocity of all electromagnetic radiations | 3 x 10^8 (pg. 225) |
| Unit of measure for frequency. | Hertz (Hz). (pg. 225) |
| More energetic radiations have ... | Shorter wavelengths and higher frequencies (pg. 225) |
| Radiations that are energetic enough to rearrange atoms in materials through which they pass. | Ionizing radiation (pg. 226) |
| Medical/dental x-rays and nuclear medicine studies account for approximately _____ of the man made radiation exposure in the United States. | 79% (pg. 226) |
| Two types of interactions in which x-ray photons are produced at the anode of an x-ray tube. | Bremsstrahlung (braking) and Characteristic (pg. 227) |
| Type of x-ray production where the negative charged electron is attracted to the positively charged nucleus of the tungsten atom, and as a result, pulled of course and redirected toward the nucleus. | Bremsstrahlung Radiation (pg. 227) |
| X-ray production where a high-speed electron encounters a tungsten atom within the anode and ejects a k-shell electron, thereby leaving a vacancy that gets filled. | Characteristic Radiation (pg. 227) |
| K-characteristic primary x rays from a tungsten target have _______ energy. | 69 keV. (pg. 227) |
| Percentage of the x-ray beam that is comprised of characteristic radiation | 10-30%. (pg. 227) |
| The gradual decrease in exposure rate as ionizing radiation passes through tissues | Attenuation (pg. 227) |
| Type of interaction in which the total energy of an x-ray photon is used to eject an inner shell electron. | Photoelectric effect (pg. 228) |
| Type of x-ray interaction with matter in which an x-ray photon ejects an outer shell electron. | Compton scatter (pg. 228) |
| Linear dose response relationships are... | responses that are directly related to the dose received. (pg. 230) |
| Dose response relationship in which the effects are not proportional to the dose. | Nonlinear relationships (pg. 230) |
| Type of radiations that deposit less energy in cells/tissues | Low LET radiations (pg. 230) |
| Annual U.S. background dose | Approximately 3 mSv (300 mrem). (pg. 230) |
| Effects that occur randomly and are "all or nothing." | Stochastic effects (pg. 231) |
| A non-threshold dose-response curve indicates | There is no safe dose to radiation (pg. 231) |
| Effects that appear a short time after exposure, usually as a result of high doses in short periods of time, and should not be seen in diagnostic radiology. | Early effects (pg. 231) |
| Effects that can appear years after exposure, including carcinogenesis, cataractogenesis, embryologic effects, and life-span shortening. | Late effects (pg. 231) |
| Two categories of risks associated with exposure to ionizing radiation | Deterministic and Stochastic (pg. 232) |
| According to the Law of Bergoni and Tribondeau, what types of tissues are particularly radiosensitive | Stem (undifferentiated, or precursor) cells, young/immature tissues, and highly mitotic cells. (pg. 233) |
| A number assigned to different types of ionizing radiations so that their effect(s) may be better determined | Radiation Weighting Factors (pg. 233) |
| A number that represents the relative tissue radiosensitivity of the irradiated material. | Tissue Weighting Factors (pg. 233) |
| True or false: The radiation weighting factor is dependent upon the linear energy transfer (LET) of that particular radiation. | True (pg. 233) |
| Product of absorbed dose and its radiation weighting factor | Equivalent Dose (EqD). (pg. 233) |
| Effective dose formula | Radiation weighting factor x tissue weighting factor x absorbed dose. (pg. 233) |
| The rate at which radiation deposits energy as it passes through tissue is termed... | Linear Energy Transfer (LET). (pg. 234) |
| Principle interactions that occur between x-ray photons and body tissues in the diagnostic x-ray range. | Photoelectric effect and Compton scatter. (pg. 234) |
| Occurs when the ionizing particle interacts directly with the key molecule (DNA) or another critical enzyme or protein (i.e. RNA). | Direct Effect (pg. 234) |
| Which molecular effect of ionizing radiation, direct or indirect, occurs most often? | Indirect effect (pg. 234) |
| Effect where ionizing radiation breaks water molecules into smaller molecules, often producing one or more atoms having unpaired electrons ("Free radicals"). | Indirect effect (pg. 234) |
| Percentage of radiation induced cell damage that is repairable. | 90% (pg. 235) |
| The most radioresistant adult somatic tissue | Nerve cells (pg. 235) |
| As the LET of ionizing radiation increases, the radiation's ability to produce biologic damage _________. | Increases (pg. 236) |
| The most radiosensitive cell | Lymphocyte (pg. 237) |
| Defined as the average annual gonadal dose to the population of childbearing age and estimated to be 20 mrem. | Genetically significant dose (pg. 239) |
| Duration in which early somatic effects become visible | Minutes, hours, days, or weeks. (pg. 240) |
| Duration in which late somatic effects become noticeable | Years after initial exposure. (pg. 240) |
| After a radiation dose of ________ to the skin, mild erythema will result in 1-2 days. | 2 Gy or 200 rad. (pg. 241) |
| Exposure that can cause depletion of lymphocytes. | 0.25 Gy or 25 rad threshold. (pg. 241) |
| Gastrointestinal syndrome (ARS) occurs at doses between... | 1,000-10,000 rad (10-100 Gy). (pg. 241) |
| Central nervous system or cardiovascular (ARS) syndrome occurs at doses greater than .... | 5,000 rad (50 Gy). (pg. 241) |
| Four stages of Acute Radiation Syndrome (ARS). | Prodromal, latent, manifest illness, and recovery or death. (pg. 241) |
| Types of late somatic effects | Carcinogenesis, cataractogenesis, embryological effects, lifespan shortening, reproductive risks, and systemic effects. (pg. 242) |
| Purpose of beam restriction | Reduces patient dose, reduces production of scattered radiation, and improves image quality. (pg. 250) |
| Most efficient beam-restricting device | Collimators. (pg. 250) |
| National Council on Radiation Protection and Measurements (NCRP) guidelines for collimator accuracy | Must be accurate within 2% of the source-to-image-receptor distance. (pg. 252) |
| Technical factor that controls the quantity of ionizing radiation | milliampere-seconds (mAs). (pg. 253) |
| Main purpose for filtration in the x-ray tube | Hardens the beam to reduce patient dose. (pg. 253) |
| NCRP added filtration requirements for x-ray equipment. | <50 kV = 0.5 mm Al equivalent 50-70 kV = 1.5 mm Al equivalent >70 kV = 2.5 mm Al equivalent. (pg. 253) |
| Conditions in which gonadal shielding should be used. | If the gonads lie in or within 5 cm of the collimated field, the patient has reasonable reproductive potential, and if diagnostic objectives permit. (pg. 255) |
| True or False: Entrance skin dose is significantly greater than exit dose. | True (pg. 257) |
| True or False: AEC can compensate for differences in screen speeds. | False, it can not compensate for screen speeds outside of what it has been programmed for. (pg. 259) |
| Primary function of grids and air-gap technique. | Remove scatter and improve radiographic contrast. (pg. 260) |
| Negative aspects to using grids. | Increases patient dose, and higher grid ratios decrease tube/grid positioning latitude. (pg. 261) |
| Reproducibility for a given group of exposure factors must not exceed ______ according to NCRP guidelines. | 5% (pg. 262) |
| NCRP guidelines for linearity state that any variation in output intensity must not exceed _____. | 10% (pg. 262) |
| Source to skin distance in stationary fluoroscopic equipment. | 15 inches (pg. 263) |
| Source to skin distance for mobile fluoroscopy. | 12 inches (pg. 263 |
| True or false: x-ray tube housing must keep leakage radiation to less than 100 mR/hr when measured 1 m. from the tube. | True (pg. 262) |
| Table top intensity of the fluoroscopy beam must be fewer than ________. | 10 R/min (100 mR/hr). (pg. 263) |
| How often should intensifying screens be cleaned? | At least every 6 months. (pg. 263) |
| Occupation dose equivalent limit. | 5 rem/y (50 mSv/y). (pg. 269) |
| Lead equivalent requirement for bucky-slot covers, lead curtain(drape), lead apron, and lead gloves. | Minimum of 0.25 mm of lead (pg. 270 & 271) |
| Law that states if distance doubles, exposure dose will be cut to 1/4, and if distance is cut in half, exposure dose will be 4 times the original. | Inverse square law (pg. 272) |
| NCRP requirements for primary protective barriers. | Walls with 1/16 inch (1.5 mm.) lead thickness, and 7 feet in height. (pg. 272) |
| NCRP requirements for secondary protective barriers. | 1/32 inch lead. (pg. 272) |
| Are lead aprons, gloves, and other apparel, primary or secondary barriers? | Secondary (pg. 273) |
| Gestational dose limit to a fetus must not exceed _______. | 500 mrem (5 mSv). (pg. 274) |
| Required length of the cord on x-ray equipment. | At least long enough to allow radiographer to stand 6 feet from the x-ray tube and patient. (pg. 275) |
| Traditional radiation units of measurement. | Roentgen, rad, and rem. (pg. 281) |
| SI radiation units of measurement. | Air Kerma (Gya), Gray (Gyt), Sievert (Sv). (pg. 281) |
| Measurement of ionization in air | Roentgen (pg. 281) |
| The term rad is an acronym for... | radiation absorbed dose (the Gray is the SI unit). (pg. 282) |
| The accronym rem stands for ... | radiation equivalent man (the sievert is the SI unit). (pg. 282) |
| The Code of Federal Regulations states that monitoring be provided for occupationally exposed individuals in a controlled area who are likely to receive more than ___________. | 1/10 the dose-equivalent limit. (pg. 283) |
| Optically Stimulated Luminescense dosimeters can measure radiation doses as low as ... | 1 mrem (pg. 284) |
| Film badges can measure radiation doses as low as... | 10 mrem (pg. 285) |
| Thermoluminescent dosimeters can record doses as low as... | 5 mrem (pg. 285) |
| Benefit of pocket dosimeters | Immediate, on-site dose readings (pg. 285) |
| Disadvantage to pocket dosimeters | Do not provide a permanent legal record of exposure. (pg. 286) |
| Occupationally exposed individuals 18 years of age and older must not receive exposure in excess of _________. | 5 mrem(50 mSv)/year. (pg. 288) |
| A radiography student participating in clinical education before the age of 18 years must not receive an annual dose of ________. | more than 0.1 rem (100 mrem). (pg. 289) |
| General population annual dose to ionizing radiation is ________. | 0.5 rem (5 mSv)/year. (pg. 289) |
| Lifetime cumulative exposure for occupationally exposed individual. | 1 rem x age in years (pg. 289) |
| Monthly occupational fetal dose limit. | Not to exceed 0.05 rem (0.5 mSv). (pg. 289) |
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jksmith1
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