Deck 11: Automatic Exposure Control

Question 1

It is easy, with AEC, to use image receptors with different speeds because the detectors can sense image receptor speed.

Answer 1

False

Question 2

What is the appropriate setting for backup time/mAs?

A) 50% of the expected mAs
B) 100% of the expected mAs
C) 150% of the expected mAs
D) 400% of the expected mAs

Answer 2

150% of the expected mAs

Question 3

AEC eliminates the need for the radiographer to select the actual _____ the examination will require.

A) kVp
B) SID
C) time
D) focal spot size

Answer 3

time

Question 4

What is the purpose of setting a backup time/mAs?

A) To prevent excessive exposure of the patient
B) To make certain the contrast is acceptable if the chosen kVp is too low
C) To make certain the density is acceptable if the patient moves
D) To prevent the selection of the wrong detector

Question 5

Where is the sensor located in an automatic exposure device with a gas-filled chamber?

A) In front of the patient
B) Behind the Bucky tray
C) In front of the image receptor
D) on the table-top

Question 6

Where is the sensor located in an automatic exposure device that converts light into an electrical signal?

A) In front of the patient
B) Behind the image receptor
C) In front of the image receptor
D) On the table-top

Question 7

Which exposure variable is controlled by the automatic exposure control device?

A) kVp
B) Focal spot size
C) Seconds
D) mA

Question 8

When using AEC, what should the radiographer adjust to manipulate the contrast of the image?

A) kVp
B) Detector location
C) Time
D) Focal spot size

Question 9

When using AEC with film-screen, what should the radiographer adjust to manipulate the overall density of the image?

A) kVp
B) Backup time
C) Focal spot size
D) Density control

Question 10

When using film-screen, what happens when an outside detector is selected for an AP thoracic spine?

A) The spine will have insufficient contrast.
B) The spine will be too dark.
C) The spine will have excessive contrast.
D) The spine will have insufficient density.

Question 11

What would happen if a film-screen radiographic exam required an exposure time faster than the minimum response time of the AEC sensors?

A) Image density would be optimal.
B) Image density would be excessive.
C) Response time has nothing to do with AEC.
D) Image contrast would be high.

Question 12

When the radiographer is considering whether to repeat a film using AEC, it is important to determine the reason why the first radiograph failed.

Question 13

What does APR stand for?

A) All programming radiology
B) Anatomically programmed radiography
C) Accurately positioned radiographs
D) None of the above

Question 14

Which automatic exposure device works by using a gas-filled chamber?

A) Phototimer
B) Diode sensor
C) Ionization chamber
D) Bucky proliferator

Question 15

A good reason to use density control is to make the film darker to compensate for improper centering.

Question 16

Why was automatic exposure control (AEC) originally developed?

A) To decrease the need for technique charts
B) To make the technologist more of a "button pusher"
C) To reduce repeats and improve image quality
D) To increase productivity and patient dose

Question 17

Which automatic exposure device works by converting x-ray photons first into light and then into an electronic signal?

A) Phototimer
B) Gas detector
C) Ionization chamber
D) Back-up timer

Question 18

Which of the following terms does not belong in the list?

A) Photodiode
B) Ion chamber
C) Ionization chamber
D) mAs readout

Question 19

What describes the shortest exposure time required for the AEC device to operate?

A) Backup time
B) Minimum response time
C) Master density time
D) a and c

Question 20

A good time to use AEC is when the radiographer is not sure where the structure to be radiographed is located.

Question 21

If the detector is directly exposed to the primary beam during a film-screen study, the area of interest will appear:

A) overexposed.
B) underexposed.
C) correctly exposed.
D) to have high contrast.

Question 22

When doing a CR study using AEC, what will happen to the patient exposure when changing from the -1 to +1 density setting?

A) Patient exposure will increase.
B) Patient exposure will decrease.
C) Patient exposure will not change.

Question 23

When doing a CR study using AEC, what will happen to the density in the area of interest when changing from the -1 to +1 density setting?

A) Density will increase.
B) Density will decrease.
C) Density will not change.

Question 24

The most common cause for repeating images done with film-screen and AEC is inaccurate:

A) kVp selection.
B) back-up mAs selection.
C) centering.
D) alignment of the tube and image receptor.

Question 25

AEC can typically be used with table-top exams.

Question 26

With modern x-ray equipment, the AEC system's minimum response time is typically:

A) 1 ms.
B) 10 ms.
C) 50 ms.
D) 100 ms.

Question 27

In order to become familiar with manual technical factors (i.e., setting mAs and kVp and not using AEC), it is very helpful to pay attention to the:

A) exposure time.
B) heat units.
C) density control.
D) mAs readout.

Question 28

When doing a film-screen study using AEC, what will happen to the density in the area of interest when changing from 70 kVp to 90 kVp?

A) Density will increase.
B) Density will decrease.
C) Density will not change.

Question 29

When doing a film-screen study using AEC, what will happen to the density in the area of interest when changing from -1 to +1 density setting?

A) Density will increase.
B) Density will decrease.
C) Density will not change.

Question 30

When exposure factors are selected using APR, the variables should not be adjusted.