Chapter 29 (Module 1)

Question 1

Distortion is a misrepresentation of
a. size only.
b. shape only.
c. size and shape.
d. detail.

Answer 1

Size and shape

Question 2

Size distortion in radiography can be ____ only.
a. foreshortening
b. magnification
c. elongation
d. minimization

Answer 2

magnification

Question 3

Size distortion is controlled by
a. SID.
b. OID.
c. radiographic distances.
d. all of the above.

Answer 3

all of the above

Question 4

As size distortion decreases, the resolution of recorded detail
a. increases.
b. decreases.
c. is not affected.
d. is altered due to digital reprocessing.

Answer 4

increases

Question 5

The ____ the SID, the ____ the degree of magnification.
a. greater; larger
b. greater; smaller
c. lesser; smaller
d. SID has no effect on magnification.

Answer 5

greater; smaller

Question 6

Examinations of body parts with a large inherent OID warrant a ____ whenever possible.
a. small SID
b. large SID
c. small SOD
d. large focal spot

Answer 6

large SID

Question 7

Which examination does not exhibit an inherently large OID?
a. AP lumbar spine
b. lateral cervical spine
c. lateral chest
d. AP facial bones

Answer 7

AP lumbar spine

Question 8

As OID increases and SID remains constant, entrance skin exposure (ESE)
a. remains unchanged.
b. decreases.
c. increases.
d. none of the above.

Answer 8

increases

Question 9

Large patients receive a greater exposure than small patients because their
a. SOD is decreased.
b. OID is increased.
c. entrance skin surface is closer to the source.
d. all of the above.

Answer 9

all of the above

Question 10

The magnification factor for a radiographic procedure is calculated at 1.25. It may be assumed that there is a ____ magnification of the object size.
a. 25 percent
b. 125 percent
c. 0.25 percent
d. 1.25 percent

Answer 10

125 percent

Question 11

Which of the following occurs when the tube or the image receptor are not properly aligned?
a. elongation
b. magnification
c. foreshortening
d. minification

Answer 11

elongation

Question 12

Which one of the following occurs when the part is improperly aligned?
a. elongation
b. magnification
c. foreshortening
d. minification

Answer 12

foreshortening

Question 13

Proper alignment is achieved when the central ray is ____ to the part and ____ to the image receptor.
a. perpendicular; parallel
b. parallel; perpendicular
c. perpendicular; perpendicular
d. parallel; parallel

Answer 13

perpendicular; perpendicular

Question 14

When the position of the patient is reversed, the direction of the tube angle must be ____ to maintain the relationship.
a. maintained
b. decreased
c. increased
d. reversed

Answer 14

reversed

Question 15

Because the x-ray beam is divergent,
a. minification is impossible.
b. minification is collimated off from the edges of the beam.
c. minification is greater with a smaller target angle.
d. minification is greater with a larger target angle.

Answer 15

minification is impossible

Question 16

X-ray tube angulations inherently
a. increase spatial resolution.
b. change the SID.
c. introduce magnification to some degree.
d. both b and c.

Answer 16

both b and c

Question 17

X-ray tube angulations inherently
a. increase spatial resolution.
b. change the SID.
c. introduce magnification to some degree.
d. both b and c.

Answer 17

both b and c

Question 18

In order to achieve a true SID of 40” with an x-ray tube angle of 30 degrees, the overhead scale should read
a. 23 inches.
b. 95 cm.
c. 34.6 inches.
d. both b and c.

Answer 18

34.6 inches

Question 19

Performing a routine chest radiograph in the anterioposterior (AP) projection will
a. decrease heart size on the image.
b. demonstrate higher resolution of the anterior ribs.
c. produce improved resolution of the thoracic spine.
d. decrease breast exposure.

Answer 19

produce improved resolution of the thoracic spine

Question 20

A renal calculus that measures 0.2 mm in size
a. cannot be visualized with an effective focal spot of 0.5 mm focal spot due to penumbral overlap.
b. is best seen with magnification and a large focal spot.
c. most likely will be visualized with a small radiographic tube angle using a large target angle.
d. all of the above.

Answer 20

cannot be visualized with an effective focal spot of 0.5 mm focal spot due to penumbral overlap

Question 21

Opening up the intervertebral joints of the cervical spine would best be accomplished with
a. the patient in a PA projection at 72” SID.
b. the patient in an AP projection with a 40” SID.
c. a perpendicular central ray at 72” SID.
d. the patient in a PA projection with a 40” SID.

Answer 21

the patient in an AP projection at 72” SID

Question 22

With digital image receptors (CR/DR)
a. the geometric factors of distortion do not apply.
b. EI#s are inaccurate due to elongation distortion.
c. computer postprocessing corrects for shape distortion.
d. none of the above.

Answer 22

none of the above

Question 23

A radiographic magnification factor(MF) of −.15 indicates
a. the object size and image size are nearly equal.
b. nothing, since negative MF is not possible.
c. the image size is smaller than the object size.
d. a change in OID is needed.

Answer 23

nothing, since negative MF is not possible

Question 24

Enlargement of a digital radiographic image on the review monitor, is an example of
a. purposeful geometric magnification.
b. electronic magnification.
c. shape distortion.
d. digital histogram distortion.

Answer 24

electronic magnification

Question 25

Positioning patients is intended to eliminate anatomical superimposition, from a radiologist perspective. To optimize image resolution it is best to
a. keep the central ray and receptor perpendicular to the patient’s anatomy, and rotate the part.
b. minimize central angulation and rotate the part only slightly.
c. use the small focal spot and extend the degree of part rotation.
d. lower the SID and increase the OID with part rotation.

Answer 25

keep the central ray and receptor perpendicular to the patient’s anatomy, and rotate the part.

Question 26

Shape distortion is calculated
a. as the ratio of SID and SOD.
b. using the tube angle and OID.
c. automatically in the computer postprocessing.
d. none of the above.

Answer 26

none of the above