Chapter 10

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1

When the speed of screen-film systems doubles, for example, when changing from a 200-speed to a 400-speed system, patient radiation exposure is _____ by approximately _____%.

increased; 25

increased; 50

reduced; 25

reduced; 50

reduced; 50

2

CR imaging has greater _______ flexibility than does conventional screen-film radiography.

kilovoltage

milliamperage

time of exposure

x-ray beam collimation

kilovoltage

3

In standard image intensification fluoroscopy, an x-ray beam half-value-layer (HVL) of 3- to 4-mm aluminum is considered acceptable when peak kilovoltage ranges from:

50 to 60

60 to 70

70 to 80

80 to 100

80 to 100

4

When settings are changed from one mA to a neighboring mA station, the most that linearity can vary is _____%.

0

10

20

50

10

5

When performing a mobile fluoroscopic procedure, to reduce the radiation exposure to the patient, the radiographer must use a minimal source-skin distance of ____ cm (____ inches).

15; 6

30; 12

38; 15

45; 18

30; 12

6

The control panel, where technical exposure factors are selected and seen on indicators by the equipment operator, must be located:

at the foot end of the radiographic examining table

at the head end of the radiographic examining table

behind a suitable protective barrier that has a r
adiation-absorbent window that permits observation of the patient during any procedure

behind any regular wall that has a regular glass window that permits observation of the patient during any procedure

behind a suitable protective barrier that has a radiation-absorbent window that permits observation of the patient during any procedure

7

To visualize smaller and lower-contrast objects during interventional procedures, high-level-control fluoroscopy uses exposure rates that are _______ those normally used in routine fluoroscopy.

higher than

lower than

the same as

none of these; smaller and lower-contrast objects cannot be visualized by fluoroscopy during interventional procedures

higher than

8

During a fluoroscopic examination a resettable cumulative timing device times the x-ray beam-on time and sounds an audible alarm or temporarily interrupts the exposure after the fluoroscope has been activated for what length of time?

1 minute

3 minutes

5 minutes

10 minutes

5 minutes

9

When using digital fluoroscopy systems, making use of the last-image-hold feature can:

be an effective dose reduction technique

eliminate the need to collimate the primary beam

eliminate increased involuntary patient motion

eliminate increased voluntary patient motion

be an effective dose reduction technique

10

Sharper size restriction of the radiographic beam is achieved when the cone or cylinder is:

longer

shorter

made of aluminum

made of durable plastic

longer

11

What is the purpose of radiographic beam filtration?

To decrease beam hardness, thereby reducing patient skin dose and the dose to superficial tissues

To increase beam hardness, thereby reducing patient skin dose and the dose to superficial tissues

To eliminate short wavelength radiation to reduce the radiation received by the patient’s skin and superficial tissues

To increase beam hardness, thereby increasing patient skin dose with only a slight increase to superficial tissues

To increase beam hardness, thereby reducing patient skin dose and the dose to superficial tissues

12

Depending on the area of the body being examined with a fluoroscopic image intensification system, for adult patients a range of ______ kVp is generally used.

30 to 60

60 to 75

75 to 110

110 to 140

75 to 110

13

When an exposed computed radiography imaging plate is ready to be processed, an imaging reading unit is used to scan the photostimulable phosphor imaging plate with a helium-neon laser beam. This results in the emission of violet light that is changed into an electronic signal by a device called a:

charge-coupled-device array

photodiode

photomultiplier tube

scintillator

photomultiplier tube

14

Of the following procedures, which involve extended fluoroscopic time?
1. Biliary drainage
2. Stent and filter placement
3. Urinary or biliary stone removal

1 and 2 only

1 and 3 only

2 and 3 only

1, 2, and 3

1, 2, and 3

15

When compared with the traditional material in the front of a cassette (aluminum or cardboard), the cassette front containing the carbon fiber absorbs approximately _____ as much radiation, resulting in a _____ dose for the patient because _____ radiographic techniques are required to produce the recorded image.

four times; higher; higher

three times; higher; higher

twice; higher; higher

half; lower; lower

half; lower; lower

16

Digital radiography images can be accessed:

at only one workstation at a time, thereby decreasing the convenience for physicians providing patient care

at no more than two workstations at a time, thereby decreasing the convenience for physicians providing patent care

at several workstations at the same time, making image viewing very convenient for physicians providing patient care

none of these; digital images cannot be accessed at any workstations by physicians

at several workstations at the same time, making image viewing very convenient for physicians providing patient care

17

Luminance is determined by measuring the concentration of light:

at only one particular point of the field of view

over a particular field of view

at only one particular point of the field of view and then squaring the number

over a particular field of view and then squaring the number

over a particular field of view

18

A radiographer uses a high-speed, rare-earth screen-film system with optimal technical exposure factors to obtain posteroanterior and lateral radiographs of a 2-year-old child’s chest. To maximize reduction of radiation exposure to the patient following adequate immobilization, the radiographer should collimate the x-ray beam so that it is _______ shield the child’s reproductive organs.

only slightly larger than the margins of the image receptor and

no larger than the margins of the image receptor and

smaller than the margins of the image receptor and

smaller than the margins of the image receptor and not

smaller than the margins of the image receptor and

19

Current federal standards limit entrance skin exposure rates of general-purpose intensified fluoroscopic units to a maximum of _____ R/min (_____ ´ 2.58 ´ 10–4 C/kg/min).

5; 5

10; 10

20; 20

25; 25

10; 10

20

Computed radiography, because of its higher exposure latitude, makes grid use on the pediatric population:

absolutely necessary for all radiographic examinations

less necessary than was previously believed

necessary only for extremity examinations

unnecessary for any examination

less necessary than was previously believed

21

Which of the following materials is commonly used in the tabletop of a radiographic examination table to make the tabletop as radiolucent as possible so that it will absorb only a minimal amount of radiation, thereby reducing the patient’s radiation dose?

Carbon fiber material

Formica

Granite

Slate

Carbon fiber material

22

Federal government specifications recommend a minimum total filtration of _____-mm aluminum equivalent for stationary (fixed) fluoroscopic x-ray units operating above 70 kVp.

1.0

1.5

2.0

2.5

2.5

23

Which of the following is not an x-ray beam limitation device?

Aperture diaphragm

Collimator

Filter

Extension cylinder

Filter

24

When a fluoroscopic image is electronically amplified by an image intensification system, which of the following benefits result?
1. Increased image brightness
2. Saving of time for the radiologist
3. Patient dose reduction

1 and 2 only

1 and 3 only

2 and 3 only

1, 2, and 3

1, 2, and 3

25

Which of the following types of filters should be used to provide uniform density when radiographing a foot in the dorsoplantar projection?

Bilateral wedge filter

Trough filter

Thoraeus filter

Wedge filter

Wedge filter