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
CR imaging has greater _______ flexibility than does conventional screen-film radiography.
kilovoltage
milliamperage
time of exposure
x-ray beam collimation
kilovoltage
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
When settings are changed from one mA to a neighboring mA station, the most that linearity can vary is _____%.
0
10
20
50
10
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Which of the following is not an x-ray beam limitation device?
Aperture diaphragm
Collimator
Filter
Extension cylinder
Filter
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
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