3 Flashcards

(33 cards)

1
Q

when using a stationary grid what is recommended for spinal filming

A

10:1 grid ratio

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2
Q

contrast bt structures of different subject densities is due to what?

A

differential absorption

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3
Q

which would have the lowest contrast

A

50 mAs with 110 kV

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4
Q

effect that scatter radiation has on a film

A

causes graying of the film

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5
Q

with all equal factors which technique would demo the most film grain (quantum mottle)

A

100 kV with 200 mA for 1/8 sec

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6
Q

the film ____ is the main function of mAs

A

density

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7
Q

a pt xray is so light you cannot see any bones at all, what change in technique should you do?

A

double mAs and increase kV by 15% more

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8
Q

pt with the ___ measurements for the AP view will have the grayest AP lumbar film

A

smallest (rutherford H, meas 20 cm)

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9
Q

to obtain a quality film for an obese pt xray, what should you do

A

lower kV in the optimal range

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10
Q

osteoporosis will usually require you to:

A

reduce the tube output

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11
Q

which rad projections routinely uses an air gap technique

A

lateral cervical

also flexion, extension, and oblique cervical

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12
Q

a film w/ a darkened overall gray appearance could be caused by:

A

exposure of the film to scatter

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13
Q

grid ____ refers to an attenuation of part of the beam by the grid

A

cut off

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14
Q

a film that is lighter on one side than the other most likely would indicate:

A

grid cut off

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15
Q

if you reduce the mAs by one half and keep the kV and distance constant, what is the outcome

A

the film density would be decreased

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16
Q

what would increase the amount of xrays passing thru the pt w/o an interaction that would prod secondary radiation?

17
Q

what three rad projections should routinely use compensating filtration

A

AP thoracic
lat thoracic
full spine

18
Q

comparing 2 films with the kV and mAs constant, one taken at 40” FFD and the other at 72” what would occur

A

increased density of 40” film

decreased image size on 72” film

19
Q

what is the 10 day rule

A

10 days after the onset of menses is the safest time to xray a female

20
Q

an accurate collimator shouldnt allow more than __% of the SID of light outside the exposure filed

21
Q

-if a film was taken at 80 kV and 100 mA for 1/2 sec
-then a second at 80 kV and 50 mA for 1 sec
-and a third at 80 kV and 200 mA for 1/4 sec
what would the outcome be?

A

they are all the same

22
Q

what is most effective in reducing SECONDARY radiation

23
Q

too high a kV will have what effect on the film

A

quantum mottle (grainy)

24
Q

__% of the mAs is equal to __% of the kV

25
what step should you take when xraying an elderly female (same as osteoporotic, bedridden)
decrease mAs by 30-50%
26
rays that exit the pt and hit the film
remnant rays
27
a lat cervical film could use what that a lat thoracic or lumbar couldnt
air gap
28
how should you reduce reproductive radiation on a 14 yo female pt with scoliosis of TS and LS
full spine film with pt facing film
29
72 yo pt gets xrays, what structure has absorbed the most xrays?
mildly osteoporotic pelvis
30
take a lat lumbar w/ 90 kV at 100 mA for 1/4 sec using 40" FFD, was too light but could see all the structures, what would you do?
increase mA by doubling it
31
took lat cervical with 66 kV at 100 mA for 1/10 sec at 72" FFD, too light but could see struct, what would you do?
increase kV by 15%
32
what is most closely related to "differential absorption"?
subject contrast
33
If a film was taken at 80 kV at 100 mA for ½ second and a second was taken at 80 kV at 50 mA for one second and a third film at 80 kV at 200 mA for ¼ second, what would be the outcome
they would all be the same