homework 9 review Flashcards
A post-processing manipulation that can be added to digital projections as a means of helping the viewer to better evaluate contrast resolution in the selected area is a
contrast mask
Additive disease processes that would require at least a 35% increase in mA include all of the following except
-pneumonia
-Paget’s disease
-pleural effusion
-ascites
Paget’s disease
All of the following are guidelines for producing optimal image histograms except
a. choose the correct body part and projection from the workstation menu.
b. leave minimal background in the exposure field through tight collimation.
c. use the smallest possible IR and cover at least 50% of it.
d. erase the imaging plate if the IR has not been used for a few days.
use the smallest possible IR and cover at least 50% of it.
All of the following are true about histogram analysis except
a. selecting the wrong body part or projection in the workstation menu will cause a histogram analysis error.
b. histogram analysis errors may occur as a result of poor central ray centering.
c. histogram analysis errors result in erroneous exposure indicator numbers.
d. fog values outside the exposure field, but included in the VOI, do not cause widening of the histogram.
D. fog values outside the exposure field, but included in the VOI, do not cause widening of the histogram.
All of the following are true about quantum noise except
a. quantum noise is demonstrated as a blotchy appearance on the image.
b. quantum noise is visualized when the exposure indicator number is higher than the ideal exposure values.
c. when present, quantum noise requires an increase in exposure factors to reduce its visualization on the image.
d. quantum noise results in excessive patient dose when present on the image.
quantum noise is visualized when the exposure indicator number is higher than the ideal exposure values
All of the following are true about windowing except
a. saving adjusted windowing settings to the PACS system narrows the dynamic range for future viewers.
b. windowing is referred to as a post-processing manipulation procedure.
c. window level adjustments change the contrast of the image.
d. windowing occurs after the image is displayed on the monitor.
c. window level adjustments change the contrast of the image.
Best practice guidelines for the use of automatic exposure control include all of the following except
- set the optimum kV for the body part.
- set the backup timer to 150% to 200% of the expected manual exposure.
- set the highest mA station for the focal spot size needed.
- wide collimation will ensure IR coverage.
4 only
Examples of artifacts that must be accepted include all of the following except
- pacemakers.
- dental bridges.
- pleural drainage tubes secured with safety pins.
- endotracheal tubes.
- heart monitoring lines
3 and 5 only
The exposure indicator number represents all of the following except the
a. amount of light given off by the imaging plate.
b. amount of exposure to the imaging plate.
c. amount of exposure to the patient.
d. measure of dose to the patient.
d. measure of dose to the patient
How many shades of gray can each pixel in a digital matrix display?
one
What is the location on a histogram graph of fat?
right
What is the location on a histogram graph of bone?
left
Which technical factor listed below is primarily used to regulate density?
mAs
Which of the following technical factors is primarily used to regulate subject contrast?
kVp
Which of the following is true about image markers?
1. They are radiopaque.
2. They should be reversed before being placed on the IR.
3. They should be positioned as close to the median plane as possible.
4. They will be magnified if positioned on the imaging table or patient.
1 and 4 onyl
