Deck 13: Automatic Exposure Control

Question 1

The predetermined level of radiation exposure needed to terminate the exposure when using AEC is set by:

A) the radiologist
B) the technologist
C) people who service the equipment
D) the manufacturer

Answer 1

people who service the equipment

Question 2

Using a higher kVp during an AEC examination results in:

A) a longer exposure time
B) a shorter exposure time
C) increased patient exposure
D) B and C

Answer 2

a shorter exposure time

Question 3

An ionization chamber is a hollow device that contains:

A) water
B) lead
C) tungsten
D) air

Answer 3

air

Question 4

Phototimer AEC detectors are usually exit-type devices because:

A) the x-rays must exit the patient to get to the detectors
B) the x-rays must exit the grid to get to the detectors
C) the x-rays must exit the image receptor to get to the detectors
D) none of the above

Question 5

Once the electric charge from an AEC detector reaches a preset point:

A) the patient can leave
B) the kVp will be reduced to 0
C) the exposure will stop
D) all of the above

Question 6

The shortest exposure time that a radiographic tube with AEC can have is the:

A) mAs readout
B) back-up time
C) minimum response time
D) density controls

Question 7

The primary purpose of AEC is to:

A) reduce patient exposure
B) control the amount of radiation reaching the IR
C) control image contrast
D) eliminate the need for the radiographer to think critically

Question 8

The actual amount of exposure used for an image when AEC is being used is the:

A) mAs readout
B) back-up time
C) minimum response time
D) density controls

Question 9

Ion chamber AEC detectors are entrance-type devices because the x-rays must:

A) enter the detector after passing through the IR
B) enter the detector before entering the patient
C) enter the detector before getting to the IR
D) none of the above

Question 10

The device that converts the light energy to an electrical signal is the:

A) photodiode
B) photocathode
C) photomultiplier tube
D) A and C

Question 11

The original type of AEC detector was the:

A) ionization chamber
B) Geiger counter
C) phototimer
D) none of the above

Question 12

There is typically a configuration of at least _________ AEC detectors in place.

A) 2
B) 3
C) 4
D) 5

Question 13

AEC controls the amount of radiation reaching the IR by controlling the:

A) time of exposure
B) mA
C) kVp
D) none of the above

Question 14

When using AEC,the radiographer is responsible for determining:

A) kVp
B) mAs
C) exposure time
D) none of the above

Question 15

The two types of detectors used in AEC are:

A) image intensifiers and phototimers
B) phototimers and ionization chambers
C) ionization chambers and Geiger counters
D) none of the above

Question 16

These can be adjusted to increase or decrease the amount of radiation needed to terminate the exposure using AEC.

A) mAs readout
B) back-up time
C) minimum response time
D) density controls

Question 17

When using AEC,the kVp:

A) is set higher than usual
B) is set lower than usual
C) is set as appropriate for the study
D) is determined by the AEC system

Question 18

The maximum length of time that an exposure lasts when using AEC is the:

A) mAs readout
B) back-up time
C) minimum response time
D) density controls

Question 19

When the x-rays enter the ionization chamber:

A) atoms become ions
B) atoms give up electrons
C) electrons and positive ions become electricity
D) all of the above

Question 20

Today's AEC system is most likely use a(n):

A) ionization chamber
B) Geiger counter
C) phototimer
D) none of the above

Question 21

When a patient for a unilateral AP hip image has a metal prosthesis covering the detector,how will the bony anatomy appear with film imaging?

A) white
B) light
C) appropriate
D) dark

Question 22

When using AEC with digital imaging,errors resulting in overexposure to the IR result in:

A) images that are dark
B) images with appropriate brightness
C) overexposed patients
D) B and C

Question 23

Using a lower mA station during an AEC examination results in:

A) reduced patient exposure
B) increased exposure time
C) decreased exposure time
D) A and B

Question 24

When your patient for an AP abdomen is very heavy,using AEC results in:

A) underexposure to the IR
B) overexposure to the IR
C) appropriate exposure to the IR

Question 25

The testing to see that the AEC device terminates the exposure at the same level of exposure,regardless of variations in other factors such as kVp or patient thickness is checking for __________________ and optical densities should be within +/- ________.

A) reproducibility;0.1
B) calibration;2
C) consistency;0.2
D) none of the above

Question 26

The detector(s)selected for an image should be:

A) the center detector because that is where the central ray is going
B) the two or three detectors that are covered by the part being imaged
C) the ones that are superimposed by the anatomic structure of interest
D) all three so that the system can work properly

Question 27

The AEC minimum response time may pose a problem when:

A) a long exposure time is needed
B) the patient can easily hold still for the exposure
C) the patient is unable to hold still for the exposure
D) all of the above

Question 28

AEC devices should be calibrated:

A) when the unit is first installed
B) at regular intervals
C) when there is a change in the type of IR being used
D) all of the above

Question 29

If the AEC detectors are not completely covered by the part being imaged and are exposed to primary radiation,:

A) the patient will be overexposed
B) the exposure will terminate very quickly
C) the IR will be exposed to the appropriate amount of radiation
D) none of the above

Question 30

If the patient for an AP thoracic spine image is centered so that the spine is not over the top of the detector:

A) the film image will be too dark
B) the film image will be too light
C) the IR will be overexposed
D) A and C

Question 31

Which of the following is the most critical aspect of successfully performing an examination using AEC?

A) centering the anatomy of interest over the detector
B) using the right mA
C) using the right kVp
D) setting the best back-up time

Question 32

In imaging a child,a short exposure time is needed for an examination using AEC.The mA setting should:

A) be low
B) be mid-range
C) be high
D) it doesn't matter-the AEC device will control the exposure time

Question 33

When there is a significant amount of scatter radiation reaching the detector,the exposure time will:

A) be shorter than needed
B) be appropriate
C) be longer than needed

Question 34

Testing to make sure the AEC system produces the same results for multiple identical exposures is checking for ______________ and the optical densities should be within +/- ______________.

A) reproducibility;0.1
B) calibration;2
C) consistency;0.2
D) none of the above

Question 35

If the back-up time is shorter than the actual exposure time needed for a properly exposed image:

A) the image receptor will be overexposed
B) the image receptor will be underexposed
C) the exposure will be appropriate

Question 36

Anatomically programmed radiography (APR)is a system in which the radiographer selects: 

A) AEC settings
B) mAs and kVp settings
C) preset settings based on the part being imaged
D) preset settings based on the size of the patient

Question 37

When the radiographer has the opportunity to set the back-up time,it should be approximately _____________ of the expected exposure time.

A) 50%
B) 150%
C) 250%
D) 600%

Question 38

The reason to have a back-up time is to:

A) protect the patient from excessive exposure
B) make sure the right mAs is used
C) keep the tube from excessive heat-loading
D) A and C

Question 39

If the radiographer is doing an upright chest using AEC but the table bucky is selected:

A) the back-up time will be reached
B) the patient will be exposed to excessive radiation
C) the IR will be overexposed
D) all of the above

Question 40

If the back-up time is set by the equipment,the exposure time should end when the mAs reaches:

A) 100
B) 400
C) 600
D) 1000

Question 41

With film-screen imaging using AEC,if an AP thoracic spine is imaged with the density setting changed from 0 to +2,the density in the area of interest will be __________________ and the exposure time will be ________________________.(Assume all other factors are appropriate. )

A) darker;longer
B) darker;shorter
C) unchanged;unchanged
D) unchanged;shorter

Question 42

Once a part has been selected using APR,the exposure factors cannot be adjusted.

Question 43

All APR settings use AEC

Question 44

With film-screen imaging using AEC,if an AP thoracic spine is imaged using 110 kVp instead of 80 kVp,the density in the area of interest will be __________________ and the image contrast will be ________________________.(Assume all other factors are appropriate. )

A) light;lower
B) dark;higher
C) the same;lower
D) the same;higher

Question 45

With digital imaging using AEC,if an AP thoracic spine is imaged using an outside instead of center detector,the brightness in the area of interest will be __________________ and the quantum noise will be ________________________.(Assume all other factors are appropriate. )

A) light;increased
B) appropriate;decreased
C) appropriate;increased
D) dark;decreased

Question 46

It is safe to assume that APR settings have been developed to produce the best quality images with the least amount of exposure.

Question 47

The AEC system will automatically adjust to changing image receptor types such as switching from a 400-speed film-screen system to a 600-speed film-screen system.

Question 48

With digital imaging using AEC,if an AP thoracic spine is imaged using 110 kVp instead of 80 kVp,the brightness in the area of interest is __________________ and the patient exposure is ________________________.(Assume all other factors are appropriate. )

A) darker;higher
B) unchanged;higher
C) lighter;lower
D) unchanged;lower

Question 49

With film-screen imaging using AEC,if an AP thoracic spine is imaged with the central ray passing 3 inches to the right of the spine,the density in the area of interest will be __________________ and the exposure time will be ________________________.(Assume all other factors are appropriate. )

A) light;long
B) light;short
C) appropriate;short
D) dark;long

Question 50

If an AEC has three detectors,only one of the three can be selected for an exposure.

Question 51

Using the plus or minus density controls should be done frequently to produce optimal images with AEC.

Question 52

With digital imaging using AEC,if an AP thoracic spine is imaged with the density setting changed from 0 to +2,the brightness in the area of interest is __________________ and the exposure time is ________________________.(Assume all other factors are appropriate. )

A) darker;longer
B) darker;shorter
C) unchanged;unchanged
D) unchanged;longer

Question 53

Phototimer AEC devices convert the radiation to light energy.

Question 54

The amount of electric charge produced in an AEC detector depends on the amount of radiation absorbed by the detector.

Question 55

When using AEC,the exit radiation is converted into an electrical signal.

Question 56

With digital imaging using AEC,if an AP thoracic spine is imaged with the central ray passing 3 inches to the right of the spine,the brightness in the area of interest is __________________ and the exposure time is ________________________.(Assume all other factors are appropriate. )

A) light;long
B) light;short
C) appropriate;short
D) dark;long

Question 57

With film-screen imaging using AEC,if an AP thoracic spine is imaged using an outside instead of center detector,the density in the area of interest will be __________________ and the patient will be ________________________.(Assume all other factors are appropriate. )

A) light;underexposed
B) light;overexposed
C) dark;underexposed
D) appropriate;underexposed

Question 58

With digital imaging using AEC,if an AP thoracic spine is imaged with the density setting changed from 0 to -2,the brightness in the area of interest is __________________ and the ____________ is increased.(Assume all other factors are appropriate. )

A) decreased;exposure time
B) increased;image contrast
C) appropriate;recorded detail
D) appropriate;quantum noise

Question 59

AED and phototiming are accurate terms that can be used in place of automatic exposure control.

Question 60

The mAs readout is of little value because there is no need to set manual exposure factors.