Ch. 33 - AEC (Exp II)

Question 1

The single function of an AEC is to eliminate the need to set…

Answer 1

Time.

Question 2

When using an AEC, the radiographer loses control of…

Answer 2

mAs.

Question 3

Automatic exposure devices provide a diagnostic quality radiograph when…

Answer 3

The anatomy of interest is positioned directly above the appropriate ionization chambers.

Question 4

Ionization chamber AECs are usually used in a ___ 3 chamber configuration.

Answer 4

3

Question 5

The most common configuration includes:

a. ) 3 chambers
b. ) A center chamber at the center of the IR
c. ) The left and right chambers slightly higher and lateral
d. ) All of the above

Answer 5

d.) All of the above

Question 6

Most AEC consoles permit activation of…

Answer 6

All 3 cells in any combination

Question 7

When more than one ionization chamber is used, the signal is…

Answer 7

Averaged

Question 8

When an AEC is used for an AP lumbar spine, which ionization chambers are utilized?

Answer 8

The center cell

Question 9

When an AEC is used for an AP hip, which ionization chambers are utilized?

Answer 9

The center cell

Question 10

When an AEC is used for a PA chest, which ionization chambers are utilized?

Answer 10

The left and right outer cells

Question 11

When an AEC is used for an AP abdomen, which ionization chambers are utilized?

Answer 11

All 3 cells

Question 12

When an AEC is used for a lateral chest, which ionization chambers are utilized?

Answer 12

The center cell

Question 13

If the primary beam is collimated from an activated chamber, the result is a…

Answer 13

Dark radiograph

Question 14

The backup time for most AECs is set at ___ of the anticipated manual exposure time.

Answer 14

150%

Question 15

U.S. public law requires that generators automatically terminate AEC exposures at ___ mAs above 50 kVp.

Answer 15

600

Question 16

Early versions of AEC technology were referred to as…

Answer 16

Phototimers

Question 17

Contemporary AEC systems work on the x-ray property…

Answer 17

Causing ionization of gases.

Question 18

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…

Answer 18

A detector was collimated out of the field of exposure.

Question 19

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…

Answer 19

18 mAs (150% of 12)

Question 20

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…

Answer 20

The mA should be decreased.

Question 21

The modern AEC systems provide a minimum response time of:

a. ) 1 millisecond
b. ) 0.001 second
c. ) 1/1,000 second
d. ) All of the above

Answer 21

d.) All of the above

Question 22

AEC density controls are properly used to compensate for…

Answer 22

Asymmetric pathology

Question 23

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…

Answer 23

34 mAs

Question 24

When using APR for 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

Answer 24

d.) All of the above

Question 25

When performing a follow-up abdomen image on a patient who recently had a small bowel study, it may be best to…

Answer 25

Deactivate the AEC and set the technique manually.