Term
|
Definition
| The reduction of the intensity of the X-ray beam as it transverses matter |
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|
Term
| Which interactions are important in radiology? |
|
Definition
| Photoelectric absorption and Compton scattering |
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Term
| Which interaction is primarily responsible for image formation? |
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Definition
|
|
Term
| What 3 end products does the photoelectric effect always yield? |
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Definition
| Characteristic radiation, a negative ion and a positive ion. |
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Term
| How does kVp affect photoelectric absorption? |
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Definition
| As kVp increases photoelectric absorption decreases. |
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Term
| Which interaction occurs with inner shell electrons of an atom? |
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Definition
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Term
| Which interaction does not produce a scatter photon? |
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Definition
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Term
| What are the effects of Compton scattering? |
|
Definition
| Film fog, accounts for most of the occupational exposure to the radiographer. |
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Term
| How does an increase in kVp affect compton scattering? |
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Definition
| as kVp increases, the effect of compton scattering increases. |
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|
Term
| What actually happens during compton scattering? |
|
Definition
| the incident photon interacts with an outer shell electron, ejecting it from orbit. |
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Term
| what happens during coherent scattering? |
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Definition
| a low-energy photon interacts with a target atom. |
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Term
| what type of radiation is formed as a result of an inner shell electron being ejected from an atom? |
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Definition
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|
Term
| what is the ALARA concept? |
|
Definition
| As Low As Reasonably Achievable |
|
|
Term
| what device is used to measure radiation exposure? |
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Definition
|
|
Term
| What is the traditional unit of exposure? |
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Definition
|
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Term
|
Definition
| amount of energy transferred from ionizing radiation to an object. |
|
|
Term
| What is the traditional unit of absorbed dose? |
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Definition
|
|
Term
| what is the SI unit of absorbed dose? |
|
Definition
|
|
Term
| what is the traditional unit of dose equivalent? |
|
Definition
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|
Term
| Which unit of measurement measures the biological effectiveness of radiation? |
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Definition
|
|
Term
| to what does the acronym LET refer? |
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Definition
|
|
Term
| Define linerar energy transfer (LET) |
|
Definition
| average energy depositer per unit path length of an object by ionizing radiation. |
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|
Term
| which of the radiation units measure the effective dose for all types of ionizing radiation? |
|
Definition
|
|
Term
| how many rad equal 1 gray? |
|
Definition
|
|
Term
| how many rem equal 1 sievert? |
|
Definition
|
|
Term
| Define genetically significant dose (GSD) |
|
Definition
| the average annual gonadal dose to members of the population who are of childbearing age |
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Term
|
Definition
| the upper level of ionizing radiation that will result in a negligible risk of bodily injury or genetic damage |
|
|
Term
| what are some characteristics of stochastic effects? |
|
Definition
They are late effects and do not have a threshold; they are "all or nothing" effects
(Cancer, leukemia, and genetic effects) |
|
|
Term
| define the term nonstochastic (deterministic) effects |
|
Definition
biologic effects of ionizing radiation the exhibit a threshold; the severity of the biologic damage increases as dose increases.
(erythmea, blood changes, epilation, cataracts) |
|
|
Term
| what is the occupational annual effective dose limit? |
|
Definition
|
|
Term
| what is the recommended cumulative dose limit for radiation workers by age? |
|
Definition
|
|
Term
| what is the monthly dose limit for exposures to the embryo/fetus? |
|
Definition
|
|
Term
| what is the total dose limit to the embryo/fetus for the entire pregnancy? |
|
Definition
| 0.5 rem or 500 mR (5 mSv) |
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|
Term
| where should a personnel dosimeter be worn during routine radiographic procedures? |
|
Definition
| at the level of the waist or chest (for fluoroscopy it should be worn at collar ouside the apron) |
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Term
|
Definition
| bean shaped structures containing enzymes that produce energy for cells |
|
|
Term
| which phase of mitosis is the most sensitive to radiation? |
|
Definition
| metaphase (high metabolic activity) |
|
|
Term
| define relative biological effectiveness (RBE) |
|
Definition
| the ability of a particular type of radiation to produce a response |
|
|
Term
| what is the relationship between LET and RBE? |
|
Definition
| direct- as LET increases RBE increases. |
|
|
Term
| which effect of ionizing radiation is most harmful to the human body? |
|
Definition
| indirect effect of ionizing radiation (because water constitutes approximately 80% of the body's total weight) |
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|
Term
|
Definition
| the theory that the cell will die if inactivation of the master molecule occurs as a result of exposure to ionizing radiation. |
|
|
Term
| what is the law of Bergonie and Tribondeau? |
|
Definition
| the radiosensitivity of cells is directly proportional to their reproductive activity and inversly proportional to their degree of differentiation. |
|
|
Term
| define the term linear in the dose-response relationship |
|
Definition
| the response is directly proportional to the dose (if the dose is doubled, the response is doubled) |
|
|
Term
| describe the term nonlinear in the dose response relationship |
|
Definition
| the biologic effect is not directly proportional to the dose, but has a more complicated relationship to dose |
|
|
Term
| describe the term nonthreshold in the dose response relationsip |
|
Definition
| any dose, regardless of its size, is expected to produce a response. |
|
|
Term
| describe the term threshold in the dose response relationship |
|
Definition
| for a small but measureable dose there is no effect. |
|
|
Term
| what effects could a linear nonthreshold curve represent |
|
Definition
| leukemia, cancer, and genetic effects |
|
|
Term
| if the radiation effects occur within minutes or days after exposure, how are they classified? |
|
Definition
early effects of radiation.
(acute radiation syndrome (nausea,vomiting, diarrhea, etc), local skin damage, hematologic depression, epilation, chromosome aberration, gonadal dysfunction |
|
|
Term
| if radiation effects are not observered for months or years, how are they classified? |
|
Definition
delayed or late effects of radiation
(cataracts, lifespan shortening, leukemia, cancer) |
|
|
Term
| what is acute radiation syndrome (ARS)? |
|
Definition
| radiation sickness that is caused by a large dose of radiation to the whole body delivered in a short period of time. |
|
|
Term
| what are the three syndromes that fall under acute radiation syndrome (ARS)? |
|
Definition
| hematologic, gastrointestinal, and cerebrovascular |
|
|
Term
| how does age affect radiosensitivity of biologic tissue? |
|
Definition
| the very young and the very old are more sensitive |
|
|
Term
| what is the most radiosensitive system in the body? |
|
Definition
|
|
Term
| what is off focus or stem radiation? |
|
Definition
| radiation emitted from parts of the tube other than the focal spot. |
|
|
Term
| radiation to light field congruence for PBL must be accurate to within what percentage of the SID |
|
Definition
|
|
Term
| how much total filtration is required for fixed x-ray units operatin at 50-70 kVp? |
|
Definition
|
|
Term
| how much total filtration is required for fixed x-ray units operating above 70 kVp? |
|
Definition
|
|
Term
| what is the disadvantage of rare earth screens? |
|
Definition
|
|
Term
| what is the purpose of the air gap technique? |
|
Definition
| reduces the amount of scatter reaching the film |
|
|
Term
| what minimum SSD should be used in radiography? |
|
Definition
|
|
Term
| how many inches should the source to tabletop distance be for fixed fluoroscopy units? |
|
Definition
|
|
Term
| what is the minimal source to tabletop distance for mobile fluoroscopes? |
|
Definition
|
|
Term
| what are the cardinal rules of radiation protection? |
|
Definition
| minimize time of exposure, maximize distance, and use shielding. |
|
|
Term
| what is the minimum lead equivalent for protective lead gloves |
|
Definition
| minimum of 0.25 mm lead equivalent |
|
|
Term
| what is the minimum lead equivalency required for protective aprons worn in fluoroscopy? |
|
Definition
|
|
Term
| what is the minimum lead equivalency required for the protective curtain on the fluoro machine? |
|
Definition
|
|
Term
| according to the inverse square law (ISL), if the distance is doubled, how will the intensity of the beam be affected? |
|
Definition
| the intensity of the beam will be decreased by 1/4. |
|
|
Term
| according to the inverse square law (ISL), if the distance is halved, how will the intensity of the beam be affected? |
|
Definition
| the intensity of the beam will be increased by 4. |
|
|
Term
| what length should the cord leading to the exposure switch be on a mobile radiographic unit? |
|
Definition
|
|
Term
| what are some effective ways to reduce patient exposure? |
|
Definition
| use high kVp techniques, maintain processor QC, usse long SID, avoid retakes, use collimation, shield. |
|
|
Term
| what is the advantage of a film badge over other types of personnel dosimeters? |
|
Definition
| the processed film constitutes a permanent, legal record of exposure. |
|
|
Term
| what type of energy is referred to as energy in motion? |
|
Definition
|
|
Term
| which type of energy is referred to as stored energy? |
|
Definition
|
|
Term
| which electrically charged particle contains the most relative mass? |
|
Definition
|
|
Term
| in which orbital shell do electrons possess the most binding energy? |
|
Definition
K shell.
binding energy increases as the distance between the shell and the nucleus decreases. |
|
|
Term
|
Definition
| an electron is bombarded and ejected from a stable atom. |
|
|
Term
| list the two types of ionizing radiation and 2 examples of each |
|
Definition
Electromagnetic radiation-x-rays and gamma rays
Particulate radiation- Alpha and Beta particles. |
|
|
Term
| state the formula for ohm's law |
|
Definition
| V=IxR (voltage = amperage x resistance) |
|
|
Term
| how many alternations per second occur with 60-HZ alternating current? |
|
Definition
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