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68 Cards in this Set
- Front
- Back
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The second generation CT scanners had the disadvantage of increased: a) number of translations b) ring artifacts c) scanning time d) beam scatter |
D |
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What is the one design feature that makes spiral CT possible? a) detector arrays b) dual focus anodes c) high voltage generators d) slip rings |
D |
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According to target theory, the target molecule of a cell is: a) water molecule b) a protein macromolecule c) the DNA in the nucleus d) any molecule in the cell |
C |
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The cell 'engines' are the: a) lysosomes b) nucleoli c) mitochondria d) ribosomes |
C |
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The _______ generation of CT scanners was the first to have the fan beam transect the entire patient at times. a) fourth b) first c) third d) second |
C |
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The two OH- free radicals can join to form _______ molecules. a) DNA b) hydrogen peroxide c) hydroperoxyl d) organic free radical |
B |
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Each CT projection is: a) printed on film b) stored on the computer c) displayed on the monitor d) all of the above |
B |
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An indirect effect from ionizing radiation occurs on a _______ molecule. a) DNA b) free radical c) water d) target |
C |
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A(n) _______ will give improved spatial resolution in multislice spiral CT imaging. a) larger detector size b) larger voxel size c) higher mA d) smaller detector size |
D |
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The first generation of CT used _______ detector(s) a) two b) six c) four d) eight |
A |
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A(n) _______ effect increases with incidence but NOT severity as the dose increases. a) stochastic b) non-stochastic c) localized d) early |
A |
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The human dose-response relationship at low ranges of radiation is calculated using a) extrapolation from high ranges b) known responses from low doses c) human experiments d) all of the above |
A |
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The Law of _______ states that the radiosensitivity of living tissue is a function of the metabolic maturation of that tissue. a) Hunter & Driffield b) Roentgen & Plank c) Bergonie & Tribondeau d) Watson and Crick |
C |
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Tissues that are _______ with a _______ metabolic rate are more radiosensitive. a) mature, high b) immature, high c) immature, low d) mature, low |
B |
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The patient dose in the CT is determined by the _______ collimator a) predetector b) prepatient c) postpatient d) A & B |
B |
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The RBE of diagnostic x-rays is equal to: a) 5 b) 10 c) 1 d) 20 |
C |
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The principal advantage of spiral CT is the ability to image a large volume of tissue with: a) a single breath hold b) less noise c) improved spatial resolution d) less processing time |
A |
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Each sweep of the source-detector around the body during CT is called a _______. a) reconstruction b) projection c) translation d) rotation |
D |
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A dose of 1000 rads given to a patient in 5 doses of 200 rads per day is a _______ dose. a) fatal b) diagnostic c) fractionated d) protracted |
C |
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The third generation of CT scanners allowed for further reduction in: a) scanning time b) scattered radiation c) fan-beam width d) A & B |
D |
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A cell is in _______ when it is not undergoing mitosis or meiosis. a) prophase b) interphase c) telophase d) anaphase |
B |
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Many CT x-ray tubes have the capacity for millions of _______ with each exam. a) heat units b) rotations c) volts d) Hertz |
A |
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Humans are most radiosensitive during: a) adulthood b) infancy c) old age d) fetal stages |
D |
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_______ is a measure of the rate that energy is transferred from ionizing radiation to soft tissue. a) MeV b) RBE c) LET d) OER |
C |
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The new development in the fourth generation CT scanner is the: a) reduced patient dose b) stationary detector array c) ring artifact d) fan beam |
B |
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The most radiosensitive target molecule in the human cell is the: a) protein b) DNA c) hormone d) glucose |
B |
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As LET _______ the RBE _______. a) increases, decreases b) increases, increases c) decreases, remains the same d) increases, remains the same |
B |
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Ionizing events from irradiation are considered to be direct effects if they occur with _______ molecules. a) water b) DNA c) protein d) both A & B |
B |
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_______ are among the most radioresistive species. a) Birds b) Cockroaches c) Dogs d) Humans |
B |
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The reduction in _______ was the principal advantage of the second generation CT scanners. a) scatter radiation b) scanning time c) image noise d) patient dose |
B |
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The _______ have the function of cleaning contaminates from the cell. a) lysosomes b) mitochondria c) chromatids d) ribosomes |
A |
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The concentration of scintillation detectors affects the _______ of the CT image. a) motion artifact b) contrast resolution c) overall density d) spatial resolution |
D |
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The _______ is the basic functional unit of all plants and animals. a) cell b) DNA c) lipid d) macromolecule |
A |
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The probability of a hit is increased with _______ and _______ radiation. a) high, low b) low, high c) high, high d) low, low |
C |
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The process of cell meiosis results in cells with _______ chromosomes each a) 46 b) 48 c) 23 d) 22 |
C |
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The LET of diagnostic x-rays is _______ keV/im. a) 0.2 b) 0.3 c) 3.0 d) 50 |
C |
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Free radicals can be damaging because they are: a) unstable b) highly reactive c) radioactive d) both A & B |
D |
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The reconstruction fo spiral CT images is done by mathematical: a) interpolation b) extrapolation c) reconstruction d) reformation |
A |
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The lethal effects of cell irradiation are measured by cell _______. a) death b) damage c) survival d) mutation |
C |
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If the response to radiation is expected no matter how small, then that dose-response is: a) linear b) nonlinear c) nonthreshold d) threshold |
C |
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During the latent period, the radiation victim experiences: a) hair loss b) nausea & vomiting c) skin erythema d) well-being |
D |
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The LD50/60 for humans is approximately _______ rads. a) 100 b) 250 c) 350 d) 1000 |
C |
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Radiation-induced genetic damage follows a _______ dose-response relationship. a) linear-nonthreshold b) linear-threshold c) nonlinear-nonthreshold d) nonlinear-threshold |
D |
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Thermoluminescence dosimeters use a crystal made up of: a) aluminum oxide b) gadolinium c) lithium fluroide d) cesium iodide |
C |
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The pixel size is reduced the the _______ size is increased and the _______ size is fixed. a) field of view, matrix b) matrix, field of view c) Hounsfield unit, field of view d) field of view, Hounsfield unit |
B |
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The theory of radiation hormesis suggests that radiation doses less than 10 rads are: a) carcinogenic b) beneficial c) lethal d) harmful |
B |
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The human application of radioprotective agents would: a) double radiation damage b) be fatally toxic c) reduce radiation effects by half d) reduce radiation effects by one-fourth |
B |
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The possible beneficial effect of a small amount of radiation is called: a) radiosensitizing b) hormesis c) radioprotection d) protraction |
B |
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Each pixel of information in the CT image contains numerical information in _______ units. a) voxel b) reconstruction c) Hounsfield d) pixel |
C |
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A _______ response to radiation is directly proportional to the dose received. a) linear b) nonlinear c) curvilinear d) nonthreshold |
A |
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The walls of a dedicated mammography room usually require: a) one HVL lead shielding b) one TVL lead shielding c) no lead shielding d) lead shielding equal to fluoro rooms |
C |
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The time from end of CT imaging to image appearance is called the _______time. a) reconstruction b) translation c) projection d) Hounsfield |
A |
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The LD50/60 in the dose of radiation to the whole body that will result in death within _______ to _______% of the irradiated population. a) 50 days, 60 b) 60 days, 50 c) 60 minutes, 50 d) 50 minutes, 60 |
B |
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In the plate reader of CR, the IP is scanned with a _______ as it is drawn into the machine. a) radiation b) light c) helium-neon laser d) cesium, iodide |
C |
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Some radiation victims of _______ syndromes may recover completely. a) central nervous system b) gastrointestinal c) hematologic d) all of the above |
C |
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Spatial resolution is improved with increased _______ in digital radiography. a) field of view b) Housnfield units c) pixel size d) matrix size |
D |
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A Geiger-Muller counter is a(n): a) scintillation detector b) optically stimulated dosimeter c) thermoluminescent dosimeter d) gas-filled detector |
D |
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The most accurate and sensitive personnel monitoring device with a wide range of sensitivity is the: a) photographic emulsion b) scintillation detector c) optically stimulated dosimeter d) ion chamber |
C |
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There is usually _______ before the symptoms of acute radiation syndromes appear. a) latent period b) recovery period c) prolonged illness d) loss of hair |
A |
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Each CT projection records variation in: a) density and contrast b) motion and noise c) tumor mass d) mass density and effective atomic number |
D |
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The spiral CT pitch is the ratio of _______ to _______. a) bed movement per 330 degrees, imaging time b) slice thickness, bed movement per 360 degrees c) bed movement per 360 degrees, slice thickness d) imaging time, bed movement per 360 degrees |
C |
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CT imaging has excellent _______ because of the narrow beam collimation. a) spatial frequency b) noise reduction c) contrast resolution d) spatial resolution |
D |
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The central nervous system syndrome occurs following a whole body dose of ______ rads or more. a) 5000 b) 2000 c) 1000 d) 500 |
A |
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The cross-sectional anatomy is translated into ______ during CT reconstruction. a) an intensity profile b) attenuation patterns c) a matrix of values d) effective atomic numbers |
C |
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The concept of effective dose accounts for the: a) different types of radiation and RBE b) relative radiosensitivity of various tissues and organs c) the person's distance from the source d) Both A & B |
D |
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The CT scanner must be calibrated so that _______ is a CT number zero. a) water b) plexiglass c) nylon d) polyethylene |
A |
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The the degree of spatial resolution in any CT image system is limited to the size of the _______. a) voxel b) FOV c) matrix d) pixel |
D |
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Immediately following a whole body dose of 1000 rads the victim would experience: a) sudden death b) latent period c) prodromal symptoms d) hair loss |
C |
