Deck 13: Minimizing Patient Dose

Question 1

The approximate entrance skin exposure (ESE) for a radiographic study taken at 90 kVp and 23 mAs is

A)57.5 mR.
B)67 mR.
C)103.5 mR.
D)2.7 R.

Answer 1

103.5 mR.

Question 2

An effective method of reducing patient exposure is to use

A)a slow speed image receptor.
B)a medium speed image receptor.
C)a grid.
D)the highest speed possible image receptor.

Answer 2

the highest speed possible image receptor.

Question 3

In an effort to reduce dose, the recommended SID for routine radiography is

A)36-38 inches.
B)40-42 inches.
C)44-48 inches.
D)56 inches.

Answer 3

44-48 inches.

Question 4

When the primary-beam field size ____, the patient exposure ____.

A)increases; decreases
B)decreases; decreases
C)decreases; increases
D)increases; increases

Question 5

In an effort to minimize patient dose,

A)the small focal spot should be used.
B)the large focal spot should be used.
C)beam filtration should be minimum.
D)none of the above.

Question 6

The use of a grid will

A)decrease patient exposure.
B)increase patient exposure.
C)have no effect on patient exposure.
D)increase kVp.

Question 7

When patient SID or SOD increases,

A)patient ESE decreases.
B)patient ESE increases.
C)patient ESE increases by the square of the distance.
D)there is no relationship between ESE and distance.

Question 8

When comparing ESE and actual dose to an area of interest,

A)actual dose is higher than ESE.
B)ESE and actual are equal.
C)the actual dose and ESE are inverse.
D)actual dose is lower than ESE.

Question 9

Entrance skin exposure is a/an ____ exposure.

A)maximum
B)minimum
C)average
D)theoretical

Question 10

To reduce patient exposure, the __________ consistent with image quality should be selected.

A)highest mAs
B)highest kVp
C)shortest distance
D)highest mAs and lowest kVp

Question 11

The radiation intensity from a diagnostic x-ray unit will vary in a/an

A)direct relationship with mAs.
B)direct relationship with the square of the kVp.
C)inverse relationship with the square of the distance.
D)all of the above

Question 12

The Food and Drug Administration (FDA) sets an entrance skin exposure limit of ____ R/min for fluoroscopic systems in the United States.

A)11.5
B)20.2
C)35.1
D)42.7

Question 13

The conscientious radiographer can reduce the patient dose by at least ____ in most examinations by choosing appropriate exposure factors.

A)100 percent
B)75 percent
C)50 percent
D)25 percent

Question 14

Skull radiography routinely includes a posterior-anterior (PA) projection.This is intended to

A)reduce dose to the lens of the eye.
B)reduce dose to the cerebellum.
C)reduce dose to the paranasal sinuses.
D)reduce dose to the thyroid.

Question 15

Which of the following radiographic procedures delivers the lowest entrance skin exposure?

A)hip
B)pelvis
C)lumbar spine
D)elbow

Question 16

Each of the following is a type of gonad shield EXCEPT

A)flat contact.
B)shadow.
C)collimator.
D)shaped contact.

Question 17

Patient entrance skin exposure decreases as

A)source-to-image receptor distance (SID) decreases.
B)SID increases.
C)source-to-object distance (SOD) decreases.
D)object-to-image receptor distance (OID) increases.

Question 18

Of the choices below, the combination of exposure factors that would minimize patient dose would be

A)24 mAs, 80 kVp, 8"x10" field size, 44" SID
B)12 mAs, 92 kVp, 8"x10" field size, 40" SID
C)6 mAs, 106 kVp, 8"x10" field size, 44" SID
D)24 mAs, 80 kVp, 10"x12" field size, 40" SID

Question 19

The maximum exposure received by the patient is at

A)the skin exit to the body.
B)the area of interest.
C)the gonads.
D)the skin entrance to the body.

Question 20

Which x-ray generator will substantially decrease the patient entrance skin exposure?

A)single-phase, unrectified
B)single phase, rectified
C)three-phase, 6-pulse
D)three-phase, 12-pulse

Question 21

Match the following choices with the correct answer as each relates to minimizing patient radiation dose.
1.7 mR/mAs

A)60 kVp
B)shaped contact
C)focal spot size
D)distance (SID)
E)44-48 inches
F)AP supine abdomen position
G)oblique projection of the abdomen
H)18 mAs @ 70 kVp

Question 22

A radiographic examination of the small bowel for a 25-cm abdomen was performed doing a 15-min PA; 30-min PA; 60-min PA; and 90-min PA radiograph.What is the total approximate entrance skin exposure if each radiograph was produced at 100 kVp, 25 mA, and 40 in (100 cm)? According to calculations, 100 kVp = 5.6 mR/mA.

Question 23

What is the approximate entrance skin exposure in mR for the fluoroscopic examination of the stomach performed for 4.5 minutes at 110 kVp at 1.7 R/min?

Question 24

What is the approximate entrance skin exposure for a 15-cm AP abdomen produced at 70 kVp, 20 mA, and a SID of 40 in (100 cm), if 70 kVp = 2.5 mR/mA?

Question 25

Match the following choices with the correct answer as each relates to minimizing patient radiation dose.
has no impact upon patient dose

A)60 kVp
B)shaped contact
C)focal spot size
D)distance (SID)
E)44-48 inches
F)AP supine abdomen position
G)oblique projection of the abdomen
H)18 mAs @ 70 kVp

Question 26

Match the following choices with the correct answer as each relates to minimizing patient radiation dose.
male gonadal shielding

A)60 kVp
B)shaped contact
C)focal spot size
D)distance (SID)
E)44-48 inches
F)AP supine abdomen position
G)oblique projection of the abdomen
H)18 mAs @ 70 kVp

Question 27

Match the following choices with the correct answer as each relates to minimizing patient radiation dose.
dose relationship is inverse.

A)60 kVp
B)shaped contact
C)focal spot size
D)distance (SID)
E)44-48 inches
F)AP supine abdomen position
G)oblique projection of the abdomen
H)18 mAs @ 70 kVp

Question 28

Match the following choices with the correct answer as each relates to minimizing patient radiation dose.
lowers dose to the kidneys

A)60 kVp
B)shaped contact
C)focal spot size
D)distance (SID)
E)44-48 inches
F)AP supine abdomen position
G)oblique projection of the abdomen
H)18 mAs @ 70 kVp

Question 29

What is the approximate entrance skin exposure for a 20-cm AP pelvis produced at 80 kVp, 20 mA, and a SID of 40 in (100 cm), if 70 kVp = 2.5 mR/mA?

Question 30

Match the following choices with the correct answer as each relates to minimizing patient radiation dose.
45 mR ESE

A)60 kVp
B)shaped contact
C)focal spot size
D)distance (SID)
E)44-48 inches
F)AP supine abdomen position
G)oblique projection of the abdomen
H)18 mAs @ 70 kVp