Chapter 27 (Module 1)

Question 1

The recorded detail of a digital radiographic image is primarily visible because of
a. sufficient contrast.
b. sufficient receptor exposure.
c. low signal to noise ratios (SNR).
d. both a and b.

Answer 1

both a and b

Question 2

The difference between two adjacent gray shades on a radiographic image is
a. recorded detail.
b. quantum mottle.
c. radiographic contrast.
d. distortion.

Answer 2

radiographic contrast

Question 3

A radiograph with few shades of gray exhibits
a. low contrast.
b. high contrast.
c. medium contrast.
d. long scale contrast.

Answer 3

high contrast

Question 4

Which type of radiograph provides the most clinical information?
a. an image with quantum mottle
b. short-scale contrast images
c. low-density images
d. low-contrast images

Answer 4

low-contrast images

Question 5

The principal controlling factor of radiographic contrast using film-screen technology is
a. kVp.
b. mAs.
c. focal spot size.
d. anode angle.

Answer 5

kVp

Question 6

A radiograph that demonstrates considerable differences between gray shades is said to have
a. short scale.
b. high contrast.
c. increased contrast.
d. all of the above.

Answer 6

all of the above

Question 7

A radiograph that demonstrates minimal differences between gray shades is said to have
a. long scale.
b. low contrast.
c. decreased contrast.
d. all of the above.

Answer 7

all of the above

Question 8

With digital imaging technologies, the final brightness and contrast appearance of an image is due to
a. kVp.
b. window and level controls.
c. look-up table (LUT) application.
d. image rescaling.

Answer 8

look-up table (LUT) application

Question 9

A frontal projection chest radiograph that demonstrates a faint outline of the thoracic spine and many shades of gray to show the pulmonary markings of the lungs illustrates
a. underpenetration.
b. long-scale contrast and adequate penetration.
c. overpenetration.
d. short-scale contrast and adequate penetration.

Answer 9

long-scale contrast and adequate penetration

Question 10

Image receptor contrast of radiographic film is expressed as the ____ of the D log E curve.
a. slope
b. toe
c. shoulder
d. speed

Answer 10

slope

Question 11

In digital imaging using a DR detector, image contrast decreases with
a. excessive kVp values.
b. underexposure.
c. mAs values that are too low.
d. radiographic grids.

Answer 11

excessive kVp values

Question 12

Varying tissue thicknesses and densities is referred to as
a. differential absorption
b. attenuation
c. subject contrast
d. image contrast

Answer 12

subject contrast

Question 13

As kVp ____, a ____ range of photon energies is produced.
a. increases; wider
b. increases; narrower
c. decreases; wider
d. decreases; longer

Answer 13

increases; wider

Question 14

A high contrast LUT applied to a chest radiograph would yield
a. dark lung fields and poorly demonstrated lung mediastinal anatomy.
b. very few gray shades between the darkest and lightest regions of the chest.
c. underpenetrated lung fields and a clear silhouette of the thoracic spine.
d. excellent visualization of the bronchopulmonary markings and ribs.

Answer 14

very few gray shades between the darkest and lightest regions of the chest

Question 15

High contrast is directly related to
a. the number of photoelectric interactions.
b. high kVp.
c. the amount of Compton scatter.
d. mAs.

Answer 15

the number of photoelectric interactions

Question 16

Immediately after exposure and before a digitally acquired image is post-processed, the initial image shown demonstrates
a. very low contrast
b. the heel effect
c. focal spot blur
d. extremely high contrast

Answer 16

very low contrast

Question 17

Which of the choices below does not increase contrast?
a. increasing grid ratio
b. increasing the amount of irradiated tissue
c. decreasing filtration
d. decreasing kVp

Answer 17

increasing the amount of irradiated tissue

Question 18

Radiographic image contrast is a combination of
a. grid ratio and field size
b. receptor contrast and subject contrast
c. filtration thickness and field size
d. data rescaling and look-up tables

Answer 18

receptor contrast and subject contrast

Question 19

As kVp increases, the percentage of Compton interactions _______ and contrast_______.
a. decreases; decreases
b. decreases; increases
c. increases; decreases
d. increases; increases

Answer 19

increases; decreases

Question 20

When the tissue structure of the ankle joint is considered, the dramatic tissue differences between the muscles and bones of the ankle produce
a. high subject contrast.
b. low subject contrast.
c. high receptor contrast.
d. low receptor contrast.

Answer 20

high subject contrast

Question 21

A fluoroscopic examination that uses barium as a contrast material would typically produce images with
a. long scale contrast.
b. short scale contrast.
c. low contrast.
d. both a and c.

Answer 21

short scale contrast

Question 22

The total amount of irradiated material is a function of
a. tissue thickness and tissue density.
b. body part thickness and area of exposure.
c. field size and anode angle.
d. body position and focal spot size.

Answer 22

body part thickness and area of exposure

Question 23

A radiographic grid with a K-factor of 1 would offer
a. a 100 percent increase in contrast.
b. no change in image contrast.
c. a reduction in image contrast.
d. an increase in exposure with a decrease in contrast.

Answer 23

no change in image contrast

Question 24

In order to reduce patient entrance skin exposure (ESE), higher kVp exposures are a consideration. It is important to remember that
a. kVp values that are too high can short-circuit a digital detector.
b. kVp values that are excessively high can negatively impact the data histogram.
c. a significant loss of image contrast is not a reason to avoid higher kVp values in order to reduce ESE.
d. the digital processing software will correct for any kVp value regardless of how high it is in value.

Answer 24

kVp values that are excessively high can negatively impact the data histogram

Question 25

With increasing kVp levels, it is important to remember that with digital receptors and DR technologies
a. less differential absorption occurs and a narrower histogram results.
b. the difference between minimum and maximum incoming photon energies is reduced.
c. more anatomical data can be recorded with a lower patient dose.
d. all of the above.

Answer 25

all of the above

Question 26

Kilovoltage peak (kVp) controls the proportional relationship of
a. mAs and kVp.
b. Compton and photoelectric interactions.
c. photoelectric and characteristic interactions.
d. SID and patient thickness.

Answer 26

Compton and photoelectric interactions

Question 27

What should you expect to occur with a decrease in kVp, using digital receptors?
a. an increase in Bremsstrahlung tissue interactions
b. more Compton interactions
c. a narrower histogram
d. more photoelectric interactions

Answer 27

more photoelectric interactions

Question 28

When digital imaging receptors are used,
a. kVp is not a consideration.
b. radiographic grids are not necessary.
c. an exposure at 90 kVp would require a grid.
d. Compton scatter is not a factor.

Answer 28

an exposure at 90 kVp would require a grid

Question 29

All of the following factors would affect radiographic subject contrast EXCEPT
a. part thickness.
b. average tissue density.
c. using barium as a contrast agent.
d. LUT selection.

Answer 29

LUT selection

Question 30

An increase in x-ray beam filtration
a. increases the number of Compton interactions.
b. reduces contrast.
c. increases the average photon energy.
d. all of the above.

Answer 30

All of the above

Question 31

When choosing between two radiographic grids, the k factor is different. Choosing a grid with the higher K factor
a. produces an image with lower contrast.
b. results in a higher degree of scatter and secondary radiation clean-up.
c. will improve recorded detail.
d. requires a reduction in mA to compensate for the added subject contrast.

Answer 31

results in a higher degree of scatter and secondary radiation clean-up

Question 32

With digital imaging systems, the primary factors affecting final image contrast are the
a. window level and brightness.
b. histogram and look-up table (LUT).
c. EI numbers and S numbers.
d. kVp and mAs.

Answer 32

histogram and look-up table (LUT)

Question 33

Selecting an open-mouth odontoid LUT and applying this LUT to a KUB, will yield a final image with
a. low contrast and reduced visibility of detail.
b. many subtle gray shades and a longer scale of contrast.
c. high contrast visualization of lumbar spine anatomy.
d. the look of a high kVp exposure and quantum noise.

Answer 33

High contrast visualization of lumbar spine anatomy