Deck 8: Exposure Technique Selection

Question 1

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

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

Answer 1

Seconds

Question 2

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 tabletop

Answer 2

In front of the image receptor

Question 3

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) Backup timer

Answer 3

Phototimer

Question 4

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 5

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

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

Question 6

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

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

Question 7

Why was automatic exposure control (AEC)developed?

A) To decrease the need for technique charts
B) To make the radiographer more of a "button pusher"
C) To determine the radiation exposure required to produce a quality image
D) To increase the productivity and the patient dose

Question 8

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 9

What would the result be if a film-screen radiographic examination required an exposure time shorter 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 10

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 B
E) A and C

Question 11

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 12

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 13

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 14

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

A) kVp
B) Detector selection
C) Exposure time
D) Focal spot size

Question 15

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

Question 16

Which of the following is a system that allows the radiographer to select a particular button on the control panel that represents an anatomic area and displays a preprogrammed set of exposure factors?

A) mAs readout
B) Anatomically programmed technique
C) Automatic exposure control
D) Phototiming

Question 17

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

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

Question 18

Once a predetermined amount of radiation is transmitted through a patient to the AEC detector,which of the following occurs?

A) The x-ray exposure increases.
B) The x-ray exposure decreases.
C) The x-ray exposure terminates.
D) A and B.

Question 19

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

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

Question 20

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 tabletop

Question 21

Where does a radiographer find the established guidelines for selecting exposure factors for a radiographic examination?

A) Technique chart
B) Generator control panel
C) Examination requisition
D) A or B
E) B or C

Question 22

Exposure time will ______ using AEC when patient thickness decreases.

A) decrease
B) remain the same
C) increase
D) double

Question 23

Radiographic contrast would be standardized with the:

A) variable kVp-fixed mAs technique chart design.
B) variable kVp-variable mAs technique chart design.
C) fixed kVp-variable mAs technique chart design.
D) fixed kVp-fixed mAs technique chart design.

Question 24

What is the purpose of a technique chart?

A) To decrease the patient exposure by always using the highest kVp required
B) To ensure consistent image quality
C) To reduce the repeat imaging due to technique error and, in turn, reduce the patient exposure
D) A and B
E) B and C

Question 25

If a part measures 14 cm and requires the use of 75 kVp,how much kVp would a part measuring 18 cm require when using a variable kVp-fixed mAs technique chart?

A) 67 kVp
B) 77 kVp
C) 83 kVp
D) 91 kVp

Question 26

Which of the following is/are true regarding the development of an effective technique chart?

A) The radiographic equipment must be operating properly.
B) A good-quality control program is in place.
C) The equipment must be from the same manufacturer.
D) A and B.
E) A and C.

Question 27

Which of the following is not part of a standardized technique chart?

A) SID
B) OID
C) mA
D) kVp

Question 28

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

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

Question 29

What are calipers used for?

A) To measure the mA
B) To select the kVp
C) To select focal spot size
D) To measure the part

Question 30

Accurate patient measurement is most critical for the:

A) variable kVp-fixed mAs technique chart design.
B) variable kVp-variable mAs technique chart design.
C) fixed kVp-variable mAs technique chart design.
D) fixed kVp-fixed mAs technique chart design.

Question 31

When doing a tabletop forearm study with CR,you should:

A) use AEC.
B) set manual technique.
C) A and B.

Question 32

When using a fixed kVp-variable mAs technique chart,if part thickness increases by 5 cm,what needs to happen to the mAs?

A) It should be halved.
B) It should be doubled.
C) It should be quartered.
D) It should be tripled.

Question 33

When a digital IR is overexposed due to poor use of AEC:

A) image contrast will be increased.
B) quantum noise may be highly visible.
C) patient exposure is increased.
D) patient exposure is unaffected.

Question 34

The mAs readout:

A) is of little value because it's not necessary to know mAs when using AEC.
B) reports the actual mAs used for an exposure.
C) reports the patient dose for the entire imaging study.
D) allows the radiographer to better set the mAs for an AEC examination.

Question 35

If the backup time/mAs is automatically set by the x-ray unit,the exposure should end when a maximum of _________ has been reached.

A) 600 s
B) 600 kVp
C) 600 mA
D) 600 mAs

Question 36

What is the appropriate change in kVp when using a variable kVp-fixed mAs technique chart for a 1 cm change in tissue thickness?

A) 2 kVp
B) 4 kVp
C) 6 kVp
D) 10 kVp

Question 37

What kind of chart uses a kVp value that is high enough to adequately penetrate the part but does not diminish radiographic contrast?

A) A variable kVp technique chart
B) A fixed kVp technique chart
C) A fixed mAs technique chart
D) A and B
E) A and C

Question 38

Departmental standards,such as the SID or whether an examination is done tabletop or Bucky,should be determined:

A) prior to the development of technique charts.
B) after the development of technique charts.
C) at the same time as the development of technique charts.
D) whenever the department can come to an agreement.

Question 39

With a CR system,when using AEC to image a patient who is having difficulty holding still,increasing the mA (if the unit allows)will:

A) be a bad idea because the patient will be overexposed.
B) be a bad idea because the patient will be underexposed.
C) be a good idea because the exposure time will increase.
D) be a good idea because the exposure time will decrease.

Question 40

A technique chart should be established for:

A) each radiographer.
B) each radiographic tube.
C) each radiologist.
D) A and B.
E) A and C.

Question 41

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 42

The technique chart will provide information as to how to recognize and compensate for additive pathology.

Question 43

A good time to use AEC is when the radiographer is unable to accurately center the x-ray beam.

Question 44

Generally speaking,patient dose will be decreased with the:

A) variable kVp-fixed mAs technique chart design.
B) variable kVp-variable mAs technique chart design.
C) fixed kVp-variable mAs technique chart design.
D) fixed kVp-fixed mAs technique chart design.

Question 45

Using the concept of comparative anatomy,if a child's elbow measures the same as an adult wrist and all other procedural variables are the same (i.e.,SID,image receptor type,etc.),the child's elbow will require _____ in comparison to the adult wrist.

A) less mAs
B) more mAs
C) the same mAs
D) higher kVp

Question 46

AEC can be used with tabletop examinations.

Question 47

Optimal kVp values for each anatomic area have been established by law.

Question 48

A good reason to use AEC density control is to increase the exposure to the IR to compensate for improper centering.

Question 49

With AEC it is easy to use multiple types of image receptors,because the detectors can sense image receptor type and make appropriate adjustments.

Question 50

Newer x-ray units may keep you from making an exposure if you've selected the table Bucky on the control panel but there's no IR in the table Bucky.

Question 51

A patient measuring 26 cm requires 20 mAs at 75 kVp based on a fixed kVp-variable mAs technique chart.What technique should be used for the next patient,who measures 34 cm?

A) 40 mAs at 75 kVp
B) 80 mAs at 75 kVp
C) 20 mAs at 91 kVp
D) 40 mAs at 91 kVp

Question 52

A variable kVp-fixed mAs chart may be most effective with:

A) geriatric patients.
B) trauma patients.
C) patients imaged with mobile equipment.
D) pediatric patients.

Question 53

When exposure factors are selected using anatomically programmed technique,the variables should not be adjusted.

Question 54

Technique charts are still needed when using AEC.

Question 55

Two identical rooms having the same generator and tube and installed at the same time do not require development of separate technique charts.The chart for one room can accurately be used in the other.

Question 56

If a technique chart is being used,and the IR is overexposed,the radiographer should assume the chart is inaccurate and come up with his or her own exposure factors.

Question 57

When the radiographer is considering whether to repeat an image using AEC,it is important to determine the reason the first radiograph failed.