Chapter 7: AEC (Automatic Exposure Control)

Question 1

designed to improve consistency of image quality and reduce repeat exposures

Answer 1

Automatic Exposure Control (AEC)

Question 2

Who introduced AEC?

Answer 2

Russell H. Morgan (1942)

Question 2

What is another name for AEC?

Answer 2

photo timing or AED

Question 3

Modern equipment uses what

Answer 3

ionization chambers

Question 4

eliminates need for radiographer to select exposure time and resultants mAs

Answer 4

AEC

Question 5

What does the technologist select?

Answer 5

• KVP
• mA
• appropriate chambers for the anatomy of interest

Question 6

What is very important for AEC?

Answer 6

patient is position correctly and accurately

Question 7

Display of technical factors actually used to expose
the radiograph
* Appears immediately after the exposure

Answer 7

mAs readout

Question 8

AEC devices provides diagnostic image quality for?

Answer 8

structures that are only positioned directly above ionization chambers

Question 9

Allows technologist to increase or decrease exposure preset to
ensure proper exposure when patient size or other conditions
differ from the average patient
* Proper collimation and equipment calibration critical

Answer 9

Density controls (intensity controls)

Question 10

AEC utilization is not a substitute for what?

Answer 10

optimum patient positioning

Question 11

when exposure terminated for AEC?

Answer 11

exposure is terminated when efficient radiation is reached

Question 12

crucial for not overexposure

Answer 12

back up timer

Question 13

what is the minimum response time for AEC?

Answer 13

typically 0.001 second or 1000th of a second

Question 14

what are the advantages of AEC?

Answer 14

• less repeat images
• ## reduce patient dose

Question 15

True or false
AEC can be used for mobile procedures?

Answer 15

false

Question 16

what is the back up timer limitation?

Answer 16

150 to 200% or 1.5 to 2 times the expected exposure

Question 17

What are some examples that causes overexposure using AEC?

Answer 17

• incorrect bucky activiated
• presence of orthopedic metal prothesis
• lead strip over detector
• density control left on + 1 or + 2 from previous patients

Question 18

What is the correct order regarding the tube, patient, and IR?

Answer 18

• tube
• patient
• table
• grid
• AEC
• IR

Question 19

What are some examples of underexposured using AEC?

Answer 19

• area of interest not centered over detector
• detector not completely covered by tissue of interest

Question 20

What happens to the AEC when doing a small patient?

Answer 20

• there’s less radiation
• less exposure time
• small mAs

Question 21

What happens to the AEC when doing a large patient?

Answer 21

• absorbs even more radiation
• longer exposure time
• larger mAs

Question 22

What number of AEC cells are used for a chest x-ray?

Answer 22

the two outer cells

Question 23

What number of AEC cells are used for T-spine and L- spine?

Answer 23

middle cell

Question 24

What number of AEC cells are used for lateral C-spine?

Answer 24

middle cell

Question 25

What number of AEC cells are used for abdomen x-ray?

Answer 25

all three cells

Question 26

What number of AEC cells are used for shoulder?

Answer 26

middle cell

Question 27

What number of AEC are used for knee x-ray?

Answer 27

middle cell

Question 28

What number of AEC are used for skull x-ray?

Answer 28

middle cell

Question 29

What number of AEC are used for hip x-ray?

Answer 29

one outer cell and one middle cell

Question 30

What number of AEC are used for pelvis x-ray?

Answer 30

the 2 outer cells

Question 31

What number of AEC are used for ribs x-ray?

Answer 31

middle cell

Question 32

what number of AEC are used for lateral chest?

Answer 32

middle cell

Question 33

There's no AEC for what type of exams?

Answer 33

- hand - foot - kids - clavicle - sternum