Self Test: Part D
List the four primary image quality factors
The amount of blackness on a processed radiograph is called
What exposure factor primarily controls radiographic density
For an underexposed radiograph, the mAs must be increased by a factor of four to produce a visible change in radiographic density.
A radiograph of the knee reveals that it is overexposed and must be repeated. The original technique used was 10 mAs. What change will improve the image during the repeat exposure?
Decrease to 5 mAs
The primary controlling factor for radiographic contrast is:
Low contrast gives
long scale (110 kV, 10 mAs)
High contrast gives
short-scale (50 kV, 800 mAs)
kV is a secondary controlling factor for radiographic density.
A low kV technique (50 kV) produces a long-scale contrast.
A radiograph of the elbow reveals that it is over exposed. The technologist wants to adjust kV rather than mAs for the repeat exposure. This is contrary to common practice. The original analog exposure factors were 70 kV and 5 mAs. What new kV setting would reduce radiographic density by one-half?
60 kV and 5 mAs
What techniques or devices will reduce the amount of scatter radiation striking the IR?
Recorded detail or spacial resolution is optimal with a long object image receptor distance (OID) and a short SID.
What best controls involuntary cardiac motion artifact?
shortening the exposure time
What spacial resolution factors increase resolution and geometric sharpness?
small focal spot
increase in SID
decrease in OID
Rather than rely on the anode heel effect, what can be used to equalize density of specific anatomy?
Which type of compensating filter is recommended for an AP projection of the shoulder?
which type of compensation filter is recommended for an axiolateral hip projection?
which type of grid cutoff is created if the CR and the face of the grid are not perpendicular to each other?
which of the following projections require the use of a grid?
Axial calcaneus (heel)
The misrepresentation of an object's size or shape projected on a radiograph is called:
To minimize radiographic distortion how should SID and OID be manipulated?
Greater SID and shorter OID
To best use the anode heel effect, the thinner aspect of the anatomic part should be placed under the cathode aspect of the x-ray tube.
The best method to reduce distortion of the joints of the hand is to keep the fingers __________ to the IR.
Which of the following factors affects spatial resolution to the greatest degree?
Use of a grid
Focal spot size
Focal spot size