Chapter 7 Flashcards
The single function of an AEC is to eliminate the need to set
a. kVp.
b. mA.
c. time.
d. all of the above.
time
When using an AEC, the radiographer loses control of
a. distance.
b. mA.
c. kVp.
d. mAs.
mAs
Automatic exposure devices provide a diagnostic quality radiograph when the
a. anatomy of interest is positioned directly above the appropriate ionization chambers.
b. proper time is set.
c. correct focal spot is selected.
d. beam filtration is minimum.
anatomy of interest is positioned directly above the appropriate ionization chambers
Ionization chamber AECs are usually used in a ____ chamber configuration.
a. one-
b. two-
c. three-
d. four-
three
The most common configuration includes
a. three chambers.
b. a center chamber at the center of the image receptor.
c. the left and right chambers slightly higher and lateral.
d. all of the above.
all of the above
Most AEC consoles permit activation of
a. all three cells simultaneously.
b. all three cells in any combination.
c. the outer cells when the center cell is inactivated.
d. the center cell and either outer cell.
all three cells in any combination
When more than one ionization chamber is used simultaneously during exposure, the signal is
a. averaged.
b. amplified to the highest value.
c. multiplied.
d. determined by the chamber with the highest exposure.
averaged
When an AEC is used for an AP abdomen, which ionization chambers are utilized?
a. the center cell
b. the left and right outer cells
c. all three cells
d. the left outer cell only
all three cells
When an AEC is used for an AP lumbar spine, which ionization chambers are utilized?
a. the center cell
b. the left and right outer cells
c. all three cells
d. the right outer cell only
the center cell
When an AEC is used for an AP hip, which ionization chambers are utilized?
a. the center cell
b. the left and right outer cells
c. all three cells
d. the left outer cell only
the center cell
When an AEC is used for a PA chest, which ionization chambers are utilized?
a. the center cell
b. the left and right outer cells
c. all three cells
d. the right outer cell only
the left and right outer cells
When an AEC is used for a lateral chest, which ionization chambers are utilized?
a. the center cell
b. the left and right outer cells
c. all three cells
d. the left outer cell only
the center cell
If the primary beam is collimated from an activated chamber, the result is a
a. light radiograph.
b. dark radiograph.
c. short exposure time.
d. decrease in radiographic density.
dark radiograph
The backup time of most AEC’s is set at ________ of the antincipated manual exposure time.
a. 10%
b. 50%
c. 100%
d. 150%
150%
U.S. public law requires that generators automatically terminate AEC exposures at ____ mAs above 50 kVp.
a. 100
b. 300
c. 600
d. 900
600
Early versions of AEC technology were referred to as
a. photometers.
b. phototimers.
c. photosensors.
d. photomultipliers.
phototimers
Contemporary AEC systems work on the x-ray property of
a. causing certain crystals to fluoresce.
b. causing ionization of gases.
c. producing small amounts of heat as they pass through matter.
d. causing biological effects.
causing ionization of gases
As you are performing a KUB radiograph on a patient using AEC, you notice that your post-exposure readout is unusually high. A possible explanation for this high reading could be
a. the kVp was too high.
b. the backup mAs was set too low.
c. a detector was collimated out of the field of exposure.
d. the minimum response time was too long.
a detector was collimated out of the field of exposure
A radiographer is performing an AP knee radiograph using AEC. The manual technique for this exam would be 12 mAs at 80 kVp. The backup mAs the radiographer should set would be
a. 6 mAs.
b. 12 mAs.
c. 18 mAs.
d. 24 mAs.
18 mAs
In the event that the mAs needed for a small anatomical structure is very small, in order to ensure the AEC terminates the exposure correctly,
a. the kVp should be increased.
b. the mA should be decreased.
c. all three detectors should be activated.
d. the large focal spot should be used.
the mA should be decreased
Most modern AEC systems provide a minimum response time of
a. 1 millisecond.
b. 0.001 sec.
c. 1/1000 sec.
d. all of the above.
all of the above
AEC density controls are properly used to
a. compensate for patient thickness.
b. balance the AEC detectors.
c. compensate for asymmetrical pathology.
d. compensate for improper positioning.
compensate for asymmetrical pathology
A new high-frequency radiographic system is being released to a customer for first clinical use. The applications person states that the AEC density controls are in 20% increments. If a normal AEC exposure of the hip is 24 mAs, a repeat exposure at +2 would yield a mAs value of
a. 26 mAs.
b. 29 mAs.
c. 34 mAs.
d. 48 mAs.
34 mAs
When using APR for a radiographic exposure,
a. AEC may be turned off manually.
b. a backup mAs is already set.
c. programmed AEC chamber selections may be reconfigured.
d. all of the above.
all of the above
When performing a follow-up abdomen image on a patient who recently had a small bowel study, it may be best to
a. deactivate the AEC and set the technique manually.
b. dramatically increase the backup mAs.
c. increase the minimum response time.
d. increase to 120 kVp.
deactivate the AEC and set the technique manually
