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55 Cards in this Set
- Front
- Back
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the principal controlling factor of radiographic image density is |
mAs |
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true or false: As mAs decreases, exposure increases |
false |
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which factor influences the number of photons reaching the IR |
mAs |
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which factor influences the average energy of photons reaching the IR |
kVp |
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the relationship between exposure and SID is |
inversely proportional to the square of the distance (inverse square law)
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a severely underexposed film image will |
be unable to visualize recorded details |
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in the event of making a single exposure that is critical to the exam success, most experienced technologists will |
overexpose the IR slightly (demonstrates more info, collecting the info, computer isn't making info up) |
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the effect of mAs upon exposure is |
directly proportional (double mAs, double darkness) |
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as you analyze your image, you come to the conclusion that it must have more exposure. As a general rule, you should increase |
mAs by 2x because it is directly related to density |
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a change in kVp, as an exposure factor affects |
average beam energy, beam intensity, & the amount of scatter production |
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the greatest factor in the production of scatter radiation is |
patient thickness (more atoms) |
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the recorded detail of radiographic image is visible because of |
sufficient contrast & density |
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the difference between two adjacent densities is |
radiographic contrast |
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a radiograph with few shades of gray exhibits |
high contrast (extremities) |
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which type of radiograph provides the most information |
low contrast image because there is a high kVp, long scale resulting in more grays (chest) |
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the principal controlling factor of contrast is |
kVp |
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a radiograph that demonstrates considerable differences between densities is called |
shore scale, high contrast, & increased contrast |
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a radiograph that demonstrates minimal differences between densities is called |
long scale, low contrast, decreased contrast |
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a radiograph that demonstrates considerable differences between densities is called |
high contrast |
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a radiograph that demonstrates minimal differences between density shades is called |
low contrast |
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contrats decreases with |
excessive density, inadequate density, & a wider range of densities |
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As kVp______, a ________ range of photon energies is produced |
increase; wider |
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a fluoroscopic examination that uses barium as a contrast material would typically produce images with |
shore scale contrast |
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after completing a radiograph using 27 mAs at 90 kVp, the image demonstrates adequate overall density but an area that is under-pentrated. In order to produce and optimum image in terms of contrast and penetration, the repeat image should be taken at |
27 mAs and 100 kVp |
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what should you expect to occur with a decrease in kVp |
more photoelectric interactions (total absorption of the photon) |
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recorded detail is |
the degree of geometric sharpness, definition, & the accuracy of structural lines actually recorded in the radiographic image |
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which can negatively impact recorded detail |
involuntary motion (heart beat, peristalsis) |
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factors affecting recorded detail include |
focal spot size |
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resolution is improved when |
OID decreases (close to the IR as possible = reduce magnification and improve definition) |
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resolution is improved when |
SID increases |
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which radiograph exhibits the best detail |
a PA chest radiograph for evaluation of the heart at 72 inch |
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when evaluating the degree of resolution on an actual radiographic image, an effective tissue to analyze is |
bony trabecular pattern |
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you have completed a chest radiograph on a 2 month old infant using a restraining device at a 72" SID. Because of the design of the device, OID is sub optimum. The image reveals good resolution of the bony anatomy but the pulmonary vasculature is blurred. The EI call is 2040. In an effort to improve the quality of the repeat image, the competent radiographer would |
raise mA and decrease the exposure time to decrease involuntary motion being present |
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distortion is a misrepresentation of |
size and shape
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size distortion in radiography can be _______ only |
magnification |
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size and distortion is controlled by |
SID, OID,& radiographic distances |
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as size distortion decreases, the resolution of recorded detail |
increases |
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the _____ the SID, the ______ the magnification |
greater ; smaller |
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examinations of body parts with a large inherent OID warrant a __________ whenever possible |
large SID |
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which examination does not exhibit an inherently large OID |
AP lumbar spine because it is closer to the IR and close to skin surface |
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as OID increases and SID remains constant, entrance skin exposure |
increases |
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large patients receive a greater exposure than small patients because their |
SOD (source to object distance) is decreased, OID is increased, & entrance skin surface is closer to the source |
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proper alignment is achieved when the central ray is ____ to the part and ____ to the IR |
perpendicular ; perpendicular |
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because the x-ray beam is divergent |
minification is impossible |
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x-ray tube angulations inherently |
change the SID & introduce magnification to some degree |
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performing a routine chest radiograph in the AP projection will |
produce improved resolution of the thoracic spine |
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an image in which the object is actually shorter |
foreshortening |
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small and large |
focal spot size |
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the same as low contrast |
long scale contrast |
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inherently magnified in AP projection |
patella |
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controls the average energy of the x-ray beam |
kVp |
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high contrast |
short scale contrast |
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controls x-ray beam quantity |
mAs |
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best seen with the patient supine |
kidneys |
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fewer shades of gray across the final image |
high contrast |
