Exposure II

When it is known in advance that a large prosthesis that would absorb a lot of radiation is present within the anatomy, the best approach for radiographing this patient is to use:

"Manual" technique, with the AEC off

For a particular radiograph, the exposure indicator shows that twice too much exposure was used. If this radiograph was taken using the AEC, what would the "density" control be set to in order for the exposure the next time this procedure is done on a similar patient?

-2

Which of the following is a typical minimum response time for an AEC circuit?

0.01 second

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

150%

Most AEC "density" controls extend or shorten the exposure time in increments of:

25%

There is typically a configuration of at least ___ in place

3

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

600

Whenever possible the configuration of activated AEC detector cells should be selected such as: A) The thickest portion of the anatomy of interest lies over an energized cell. B) The center cell is covered by the tissue of interest. C) The energized cells are covered by the tissue of interest. D) All of these. E) A and C only

A and C only

An Ionization chamber is a hollow cell that contains

Air

Even though the AEC is being used, it is still necessary for the radiographer to set the x-ray machine for: A) Optimum mA. B) Optimum kV. C)Detector Configuration. D) C and C only. E) All of these

All of these

Which of the following are recommended areas for standardization within the imaging department? A) Radiographic Projection routines. B) Exposure factors C) Image processing parameters D) All of these

All of these

With digitized imaging, the use of variable kVp, high kVp approach to radiograph technique: A) can save patient exposure. B) Can frequently present fog in the final image. C) Results in variable contrast in the final image. D) All of these

All of these

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 these

All of these

Standardizing and simplifying technique: A) Increases consistency. B) Narrows the range potential causes of equipment failures. C) Reduces the probability of errors. D) All of the these

All of these:

AEC stands for

Automatic Exposure Control

When using automatic exposure control, which of the following should be approximately doubled from the expected exposure?

Back-up time

When imaging a patient's right hip, which detector(s) should be activated?

Center detector only

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

Centering the anatomy of interest over the detector

The primary purpose of AEC is to

Control the amount of radiation reaching the IR

Pre-established guidelines used by the radiographer to select standardized manual or AEC exposure factors for each type of radiographic examination are called

Exposure technique charts

AEC should always be used for body parts with a prosthesis

False

During a radiographic procedure using AEC, the exposure time will be shorter when the spine covers the ionization chamber, as compared with air covering the chamber

False

what is defined as optimal kVp values and alter the mAs for variations in part thickness

Fixed kVp-variable mAs

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

Minimum response time

When using auromatic exposure control, if too high an mA station is used for the particular patient and body part, the patient will receive excessive exposure because of:

Minimum response time for the AEC

A projection of an adult lumbar spine is taken with AEC using 60 KvP and a "density" setting of +2, how will the image turn out?

Mottle will still be present

Exposure techniques that are pre-programmed in the x-ray machine should be:

Over-ridden and modified on occasion according to the professional judgment of the radiographer

For AEC the ionization chamber is placed between the_____ and

Patient; image receptor

When using AEC, the radiographer muse use much greater care in:

Positioning

anatomically programmed technique is a system in which the radiographer selects

Preset settings based on the part being imaged

The reason to have a back-up time is to

Protect the patient from excessive exposure and keep the tube from excessive heat-loading

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

The IR exposure exposure will be insufficient

Assuming all other factors are accurately adjusted, the exposure time with AEC is based on

The anatomy placed over the ionization chamber

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

The image receptor will be underexposed

If an AEC Exposure is used for a "frog" lateral hip projection when there is a large metallic hip prosthesis present, which of the following will most likely result?

The patient will be over exposed, and the digital radiograph may be lit or dark

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

Time of exposure

Automatic exposure controls stay on longer with larger patients because they are designed to terminate the exposure only on the basis of the:

Total dose detected

A premature baby has a body torso which is circular rather than oval in cross-section. On this patient, for radiography of the chest, when changing from the AP to the lateral projection what overall technique adjustment should be made from the AP technique?

Use about the same technique

For digital radiography, the textbook generally recommends the variable kVp approach for techniques, but it is important that mAs be changed instead of kVp if:

Violating the minimum kVp rule may result in inadequate penetration

When using AEC, which of the following would result in over-exposure to the image receptor plate?

Wrong bucky activated

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

back-up time

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

ionization chamber

Which of the following is never a necessary item for an automatic exposure technique chart?

mAs

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

mAs readout

Using a higher kVp during an AEC examination results in

shorter exposure time

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

time of exposure