Ch. 27 Contrast (Exp I) Flashcards
The recorded detail of a radiographic image is visible because of:
- Sufficient contrast
- Sufficient density
The difference between two adjacent densities is:
Radiographic contrast
A radiograph with few shades of gray exhibits:
High contrast
Which type of radiograph provides the most information?
Low contrast images
The principal controlling factor of contrast is:
kVp
A radiograph that demonstrates considerable differences between densities is called:
- Short scale
- High contrast
- Increased contrast
A radiograph that demonstrates minimal differences between densities is called:
- Long scale
- Low contrast
- Decreased contrast
A radiograph that demonstrates considerable differences between densities is called:
High contrast
A radiograph that demonstrates minimal differences between density shades is called:
Low contrast
Image receptor contrast is expressed as the _____ of the D log E curve.
Slope
Contrast decreases with:
- Excessive density
- Inadequate density
- A wider range of densities
As the slope of the D log E curve _____, contrast _____.
Increases; increases
As kVp ____, a ____ range of photon energies is produced.
Increases; wider
Contrast increases with all of the following EXCEPT:
a. Decreased kVp
b. Decreased field size
c. Decreased part thickness
d. Increased scatter
d. Increased scatter
High contrast is directly related to:
The number of photoelectric interactions
Which generator type results in the greatest decrease in contrast?
a. Single phase, 2 pulse
b. Three phase, 6 pulse
c. Three phase, 12 pulse
d. High frequency
d. High frequency
Which of the choices does not increase contrast?
a. Increasing grid ratio
b. Increasing the amount of irradiated tissue
c. Decreasing filtration
d. Decreasing kVp
b. Increasing the amount of irradiated tissue
The concept of contrast as it is displayed on a soft-copy monitor for digital images is described as:
Dynamic range
As kVp increases, the percentage of Compton interactions ____ and contrast _____.
Increases; decreases
When the tissue structure of the ankle joint is considered, the dramatic tissue differences between the muscles and bones of the ankle produce:
High subject contrast
A fluoroscopic examination that uses barium as a contrast material would typically produce images with:
Short scale contrast
The total amount of irradiated material is a function of:
Body part thickness and area of exposure
Depending upon the kVp range, a visible change in contrast will not be seen unless kVp is minimally changed:
4-12%
In order to reduce patient entrance skin exposure (ESE), higher kVp exposures are a consideration. It is important to remember that:
kVp values that are too high produce more scatter and reduce contrast
