final Flashcards
1
Q
Projectile electrons travel from _____.
A
cathode to anode
2
Q
During an exposure, most of the _____ energy of the projectile electrons is converted to _____.
A
kinetic, heat
3
Q
At the target, the projectile electrons interact with _____.
A
outer-shell and inner-shell electrons
4
Q
The efficiency of x-ray production is _____ the tube current.
A
not affected by
5
Q
Most of the heat generated at the target is due to _____.
A
outer-shell excitation
6
Q
The efficiency of x-ray production increases as _____ increases.
A
kvp
7
Q
Approximately _____ of the kinetic energy of the projectile electrons is converted to x-rays at the target.
A
1%
8
Q
Electron interactions at the inner-shell of the target atoms produce _____ radiation.
A
characteristic
9
Q
The useful characteristic x-rays from tungsten targets are ___-shell x-rays.
A
k
10
Q
Characteristic K-shell x-rays have an effective energy of _____ keV.
A
69
11
Q
Most of the x-rays produced at the target are _____.
A
bremsstrahlung
12
Q
At 55 kVp, _____ of the x-rays produced are bremsstrahlung.
A
100%
13
Q
Bremsstrahlung x-rays are produced by _____ at the target.
A
slowing electrons
14
Q
Characteristic x-rays are produced by _____.
A
released binding energy
15
Q
The quantity of bremsstrahlung radiation increases proportionately with increased _____.
A
mAs
16
Q
An exposure taken at 100 kVp would have a continuous emission spectrum with a maximum energy of _____ keV.
A
100
17
Q
The _____ of an x-ray beam is higher when the peak of the emission spectrum is further to the _____.
A
quality, right
18
Q
An increase in mAs would _____ the _____ of the emission spectrum.
A
increase, amplitude alone
19
Q
An increase in kVp would _____ the _____ of the emission spectrum.
A
increase, amplitude and position
20
Q
Changes in _____ result in directly proportional changes in the amplitude of the emission spectrum.
A
Ma, time
21
Q
The discrete portion of the x-ray emission spectrum would change position with a change in _____.
A
target material
22
Q
The amplitude of the emission spectrum with a _____ generator is _____ it is with a three-phase generator.
A
single-phase,lower
23
Q
A 15% increase in kVp is equivalent to _____.
A
doubling the mAs
24
Q
How does added filtration affect the emission spectrum?
A
reduced amplitude and a shift to the right
25
Almost all of the kinetic energy of the incident electrons is converted to
heat
26
The transfer of the incident electrons’ kinetic energy to the outer-shell electrons causing vibration of the outer-shell electron results in the emission of
infrared radiation
27
Bremsstrahlung interactions may occur only when the incident electron interacts with
the force field around the nucleus
28
Characteristic interactions may occur only when the incident electron interacts with
inner-shell electron.
29
During a characteristic interaction, the kinetic energy of the incident electron must be ____ the electron it knocks from its orbit.
greater than that of
30
During a characteristic interaction, the dropping of a higher-energy state electron into a lower-energy state “hole” results in the emission of
a photon of electromagnetic energy.
31
The energy of a characteristic photon is
the difference between the binding energy of the outer and inner shells between which the electron dropped.
32
The K shell can hold a maximum of ____ electrons.
2
33
If the peak kVp is 110, the average keV energy of the beam would be
33-44 keV.
34
The emission spectrum of an x-ray beam from a tungsten anode consists of
a characteristic spike at 69 keV., significant portion due to bremsstrahlung interactions, mixture of brems and characteristic interactions
35
Electrons traveling from the cathode filament to the anode are called
incident electrons.
36
When comparing the x-ray emission spectrum between beams produced at 70 kVp and 110 kVp
The 70 kVp beam would demonstrate less brems and higher characteristic spike
37
When the x-ray emission spectra between single- and three-phase generators are compared,
three-phase beams would have a higher average energy
38
An increasing in the velocity of the projectile electron stream across an x-ray tube will result in production of an x-ray
Photons with shorter wavelengths
39
During bremsstrahlung x-ray production process, the x -rays that are produced will contain photons:
Having energies ranging from minimal to peak energies
40
What percentage of target interaction results in the production of x-ray photons?
1%
41
Which of the following is NOT needed to produce x-rays?
Focusing cup
42
The production of heat at the anode is directly proportional to _____.
tube current
43
What is the formula for kinetic energy?
KE = .5mv2
44
Changing kinetic energy is accomplished by
changing electron velocity
45
Reducing voltage ripple
increases x ray quantity,
| increases x ray quality
46
Heat production at the target is primarily caused by ionization.
false
47
The two basic components of radiographic film are the _____ and the _____.
base, emulsion
48
The main purpose of the gelatin emulsion in radiographic film is to _____.
hold the silver halide crystals
49
Crystals in film emulsion consist of _____ and _____.
silver bromide, silver iodide
50
A contaminant in the silver halide crystal creates the _____.
sensitivity speck
51
The latent image is made up of _____ atoms.
silver
52
High contrast film contains _____ silver halide crystals of _____ size.
smaller, uniform
53
The layer of screen that lies closest to the film is the _____.
protective coating
54
The light-emitting efficiency of the intensifying screen is improved by the _____.
reflective layer
55
Screen characteristics are determined by the _____.
phosphor size, thickness, and composition
56
A phosphorescent material emits light _____.
for a period of time after stimulation
57
A screen that emits light after an exposure terminates is exhibiting _____.
screen lag
58
The ability of an intensifying screen to absorb x-rays is called _____.
detective quantum efficiency
59
Both the isotropic emission of light from screen phosphor crystals and the added reflective layer contribute to _____.
image blur.
60
The complete construction of diagnostic radiographic film includes
polyester base, adhesive material, emulsion
61
Qualities of a good film base include
Flexibility, uniform lucency, stability
62
The adhesive layer is intended to glue the
emulsion to the base
63
Each crystal is a cubic lattice of each of the following atoms EXCEPT
potassium.
64
The crystal lattice is bound together with which type of chemical bond?
ionic
65
The impurity added to the crystal lattice is called the
sensitivity speck.
66
Which type of energy primarily interacts with the radiographic film in an intensifying screen cassette?
light
67
The invisible change in the atomic structure of the crystal lattice is called the ____ image
latent
68
According to the Gurney-Mott theory, the incident photon interacts with one of the halides and ejects a/an
electron
69
Which type of film has the fastest speed?
double-emulsion, screen film
70
A small crystal size will produce ____ resolution and ____ speed.
high; slow
71
What percentage of the latent image is formed by the light photons produced from the intensifying screen?
99%
72
What percentage of the latent image is formed by x-ray photons
1%
73
An intensifying screen consists of all of the following components EXCEPT
emulsion layer.
74
When a phosphor is struck by an x-ray photon, it will emit light
in all directions.
75
The active layer of the intensifying screen is the
phosphor layer
76
The ability of a material to emit light in response to excitation is
luminescence.
77
When light is emitted from a phosphor instantaneously upon photon excitation, it is called
fluorescence
78
Light emitted from a phosphor that continues after photon excitation ends is called
phosphorescence.
79
Until the 1970s, the most commonly utilized phosphor in radiography was
calcium tungstate
80
Which one of the following is not related to resolution?
base material
81
When an insufficient quantity of photons strikes the intensifying screen, ____ will appear on the film as graininess
quantum mottle
82
To increase the speed of an intensifying screen,
increase phosphor size
83
The speed of an imaging system depends upon the
thickness of the phosphor or silver halide layer.,crystal/phosphor size., conversion efficiency of the crystal/phosphor
84
A film screen system that possesses high latitude will
produce images with many gray shades.
85
The principle action of the crystals found in the intensifying screen is the conversion of:
X-rays into visible light
86
The speed of a film-screen image receptor can be increased by
Adding a reflective layer to the intensifying screen
87
Small amounts of impurities such as sulfur are added to the silver halogen crystals in the film to aid in formation of:
Sensitivity specks
88
Since the 1960’s nearly all film base is made of
polyester
89
A supercoating placed on most modern radiographic films helps to:
Prevents scratches and fingerprints on the film emulsion
90
The purpose of the sensitivity speck is to
attract free silver ions.
91
Manual processing of radiographs took about _____.
60 minutes
92
Eastman Kodak introduced 90 second automatic processing in _____.
1965
93
An important development that led to 90 second processing was _____.
polyester film base
94
What manual film development steps are omitted from automatic film processing?
stop bath or wetting
95
What is in the second tank in an automatic processor?
fixing agent
96
The undeveloped silver is removed from the emulsion during _____.
fixing
97
The rollers in the automatic processor are part of the _____ system.
transport
98
Replenishment of fixer and developer are controlled by the _____.
microswitch
99
The speed of film transport is controlled by the _____.
drive motor and gears
100
The temperature of the _____ is the most critical in processing film.
developer solution
101
The processor must have a fine filter in place to trap bits of emulsion in _____.
developer tank
102
Developer is replenished at the rate of _____ per 14 inches of film.
60-70 ml
103
Damp film coming out of the dryer is often caused by _____.
depleted glutaraldehyde
104
The thermostat must maintain the temperature in the developing tank at about _____.
95 degree F
105
The primary purpose of radiographic processing is to convert the ____ image into the ____ image
latent; visible
106
The most variable and sensitive factor in the production of a film radiograph is the
radiographic film processor.
107
All of the following are related except one. Select the choice that is NOT RELATED to the others.
ripening
108
An image becomes visible during
development
109
A stable black metallic silver atom is formed when
positive silver ion obtains an electron.
110
When unexposed silver halides are reduced by a solution with a high concentration, this is called ____ fog.
chemical
111
If silver halide crystals have more than four silver atoms on their sensitivity specks, the crystal will be able to be
DEVELOPED
112
As the developer is in its final stages of oxidation, its color will change to
red
113
A clearing agent will bond with
unexposed silver halides
114
If the fixer is not cleared from the film, it may result in
yellowing of the emulsion after a few years
115
Developer temperatures in 90 second automatic processors fall in which of the following ranges
90-95degrees F
116
Reducing agents convert silver halide crystals into which of the following
Black metalic silver
117
Which of the following is true concerning th unexposed silver halide crystlas?
1. They are unaffected by the developer
2. They are removed by the fixer
3. They represent the latent image
1&2 only
118
Which is the correct automatic processing cycle?
develop, fix, wash, dry
119
Computed radiography cassettes and film/screen cassettes can be used interchangeably with any x-ray imaging system.
true
120
Computed radiography screens respond to radiation with _____.
photostimulable luminescence
121
A photostimulable phosphor in a metastable state will emit light _____.
I. immediately
II. when stimulated by light
III. over time
emits light immediately, when stimulated by light, and over time.
122
Europium is the _____ of the photostimulable phosphor.
activator
123
The computed radiography cassette is called a(n) _____ plate.
imaging
124
The photostimulable phosphor screen is handled in a _____. emitted
reader
125
```
The computed radiography reader is made up of _____, _____, and _____ modules.
I. mechanical
II. chemical
III. optical
IV. computer
```
I, III, IV
126
The four steps of creating an image with computed radiography are _____.
expose, stimulate, read, and erase
127
The digital imaging plate can sit for unlimited time after the erase cycle.
false
128
The laser is one of the _____ features of the computed radiography reader.
optical
129
Optical filters are used to filter out the _____ light and allow the _____ light to reach the photodetector
stimulating,emitted
130
The output signal from the photostimulable phosphor plate is converted from analog to digital by the _____.
computer controls.
131
Computed radiography and screen-film imaging both have a(n) _____.
latent image
132
Spatial resolution, contrast resolution, noise, and artifacts are identical in screen-film imaging and computed radiography.
false
133
The 400 speed film-screen systems are still faster than computed radiography image receptors
false
134
With computed radiography the contrast is _____.
constant regardless of radiation exposure
135
The computed radiography image has _____.
wide exposure latitude and improved contrast resolution
136
When switching from screen-film imaging to computed radiography, which step is eliminated?
reloading the cassette
137
The laser beam must be less than 100 µm in diameter in order to maintain _____.
high spatial resolution
138
_____ is prevented by flooding the erased imaging plate with bright light.
ghosting
139
Computed radiography imaging produces _____ gray levels.
10,000
140
Switching from screen-film imaging to computed radiography can _____ patient dose.
reduce
141
What does CCD stand for?
Charged-couple device
142
Which of the following is responsible for the storage properties of a storage phosphor screen?
Europium
143
During photostimulable luminescence, light is released:
When an electron returns to ground state
144
During photostimulable luminescence, light is released:
1. When the phosphor is stimulated by x rays
2. Over time when returning to ground state
3. When stimulated by a laser light
1, 2, and 3
145
During CR imaging, ___________ of electrons return to ground state on their own immediately.
half
146
CR plates need to be read soon after image aquisition. After what period of time will the CR signal be questionable?
8 hrs
147
The laser beam used to stimulate the SPS in the CR reader is _____________.
50-100 µm
148
Which of the following is a solid-state device that converts light into electric signal
photodiode
149
How is the IP for a CR system erased?
It is flooded with white light
150
Which of the following is responsible for the slow scan in the CR reader?
drive mechanism
151
Deviation of the slow or fast scan will cause _______________.
artifact
152
Which of the following converts the visible light to an electric signal
Photodetector,
Photomultiplier tube
CCD
153
In the CR reader, the ________________ is where the image is stored temporarily.
image buffer
154
The principle source of noise in CR imaging is:
Scatter radiation
155
IP =
Imaging plate
156
PMT =
Photomultiplier tube
157
PD =
Photodiode
158
PSL =
Photostimulable luminensce
159
PSP =
Photostimulable phosphor
160
SP =
Storage Phosphor
161
SPS =
Storage phosphor screen
162
PSPs which are arranged in a needle like fashion provide better spatial resolution than those which are arranged in a binder.
false
163
Computed radiography cassettes are more radiosensitive than radiographic film.
true
164
In the CR reader, the fast scan moves along the long axis of the SPS.
false
165
In digital radiography, spatial resolution is reduced with increased _____.
pixel size
166
The dynamic range determines the degree of _____ in the image
contrast resolution
167
The primary limitation of fanned beam radiography is _____.
long scanning time
168
Spatial resolution is controlled by ____ size.
pixel
169
Spatial resolution is controlled by ____ size.
thin film technology (TFT).
170
CCD’s are ideal for use in digital radiography because of their:
dynamic range, sensitivity, size
171
Digital radiography is more efficient in ____________ the film screen radiography.
time, space, personnel
172
Which of the following is a capture element?
cesium iodide
173
Which of the following is a coupling element?
fiber optics
174
Which of the following is a collecting element?
TFT
175
Where is scanned projection radiography most used today?
computed tomography
176
A charge-coupled device is a __________ sensitive device.
light
177
What is the main difference between indirect DR and direct DR?
light production
178
In which method of image production is radiation energy converted into electric charge and collected as electric charge?
a-Se
179
What limits spatial resolution in digital imaging?
pixel size
180
In a digital radiography system that uses TFT technology, what percentage of the pixel face does not contribute to the image
20%
181
In film screen imaging, increasing thickness of gadolium oxysulfide will:
increase speed, decrease spatial resolution
182
In direct DR, what does the x ray beam interact with?
amorphous selenium
183
Which is more important in soft tissue radiography
contrast resolution
184
What does DMIST stand for
Digital Mammography Imaging Study Trial
185
In digital mammography tomosynthesis:
3D voxel is produced, patient dose is less than with CT imaging, patient dose is similar to screen-film mammography
186
The three-dimensioanl volume of tissue that is represented in digital mammography tomosynthesis is know as what?
voxel
187
When a thin layer of amorphous selenium is struck by an x-ray photon in a direct digital radiography system, the net result is:
electron-hole pair that is detected by an array of thin-film transistors
188
With either an amorphous selenium or amorphous silicon digital radiographic imaging system the latent image is formed by an electronis signal that is stored by
An array of thin-film transistors/storage capacitors
189
In digital radiography, as pixel size decreases:
spatial resolution increases, patient dose increases
190
What does amorphous mean?
without shape
191
At low levels of radiation, a CCD system is more sensitive than screen film.
true
192
In direct digital radiography radiation is converted to light and then charged pairs.
false
193
Digital radiography allows for lower patient doses than screen-film imaging.
true
194
Spatial resolution is better in digital imaging than in screen-film imaging.
false
195
Which kVp selection would result in the most scattered x-rays in the image-forming beam?
90 kvp
196
The x-ray interaction that contributes to the clear (white) parts of the image is _____.
photoelectric interaction
197
The three primary factors influencing the intensity of scatter in the image-forming beam are _____.
kVp, field size, and patient thickness
198
Decreasing the kVp will increase _____.
patient dose
199
Photoelectric interactions increase when _____ is decreased.
kvp
200
Scatter radiation increases as _____ increases.
field size
201
The x-rays that are transmitted through the patient without interaction contribute to _____.
useful info
202
Contrast resolution is improved by _____.
tight collimation, lowering kVp, and patient compression
203
The most commonly used beam restricting device is the _____.
variable collimator
204
The use of a compression device will increase
contrast
205
Lowering kVp _____ patient dose and _____ image contrast.
increases, increases
206
The use of _____ improves contrast and reduces patient dose
collimation
207
Federal regulations passed in _____ required that positive beam limiting devices be on all manufactured x-ray collimators.
1974
208
Beam restriction with a(n) _____ is only accurate at a fixed SID.
aperture diaphragm
209
How can you improve image contrast with a heavy patient without increasing patient dose?
using tight collimation.
210
A grid is used to improve
radiographic contrast.
211
A grid absorbs
scatter radiation.
212
When an x-ray beam passes through the body,
it may pass through the body unaffected, absorbed by the body, may interact with the body and change direction
213
Photons that pass through the body unaffected produce
radiographic contrast.
214
Photon absorption within the body occurs as the result of
photoelectric interactions.
215
The atomic interaction that produces scatter radiation is
compton
216
As kVp increases,
contrast decreases, scatter increases, image receptor exposure increases
217
The greatest source of scatter during a radiographic examination is the
patient
218
The amount of scatter radiation produced increases with a/an
increase in patient thickness, larger field size,
| decrease in atomic number of the tissue
219
As a general rule, a radiographic grid is employed
for part thicknesses above 10 cm.
220
The use of a radiographic grid requires
attention to central ray angulation,an awareness of the SID, an increase in exposure factors
221
Which statement about radiographic grids is incorrect?
grid is a series of lead strips that alternate with radiopaque interspace strips
222
The purpose of moving the grid during the radiographic exposure is to
blur out the radiopaque strips
223
The radiopaque strips
Absorb scatter
Are made of dense material
Have a high atomic number
224
The ratio of the height of the lead strips to the distance between the lead strips is the grid
ratio
225
Which grid would have the greatest distance between lead strips?
6:1
226
Which grid would most effectively reduce scatter?
15:1
227
The number of grid lines per inch is the grid
frequency
228
As the lead content of a grid increases,
the ability of the grid to remove scatter increases.
229
When the lead strips run in a single direction in a grid, the grid pattern is described as
linear
230
Angulation across the long axis of a linear grid causes
grid cut off
231
A device that moves the grid during a radiographic exposure is called
Potter-Bucky diaphragm.
232
When using a radiographic grid with computed radiography (CR),
the Moire effect is a consideration.
233
What are the four primary exposure factors?
kVp, mA, time, and SID
234
Changes in kVp affect _____.
optical density, image contrast, and image noise
235
An increase in mAs causes _____ in beam quality and _____ in beam quantity.
no change, an increase
236
There is a direct relationship between the quantity of x-rays and the _____.
milliamperage
237
If mAs is increased from 20 mAs to 40 mAs, the patient dose will _____.
be doubled
238
Beam penetrability is increased if _____ is/are increased.
kvp
239
A radiograph with a long scale of contrast will have _____ latitude and _____ contrast
wide, low
240
A radiograph is taken using 75 kVp @ 20 mAs. Which change in technique would increase contrast but maintain the same density?
65 kVp @ 20 mAs
241
At least a _____% change in mAs is necessary to produce a visible change in optical density.
30%
242
A radiograph taken using 65 kVp @ 10 mAs is too light. Which technique would double the optical density while producing a wider scale of contrast?
75 kVp @ 10 mAs
243
Which technique would give the highest patient dose?
65 kVp/300 mA @ 0.1 sec
244
The small focal spot will provide a _____.
finer detail of image when less quantity of x-rays is needed
245
Beam quality is improved when the _____ is increased, but _____ has no effect on beam quality
kilovoltage, milliamperage
246
Both beam quality and beam quality are increased by _____.
voltage waveform and kVp
247
Added filtration has the effect of _____ the beam quality and _____ patient dose.
increasing, reducing
248
Which medical condition may require a lower technique?
emphysema
249
When only the optical density needs to be changed, only the _____ should be adjusted
MAS
250
Sharpness of detail can be improved by INCREASING _____.
SID
251
In a variable kVp technique chart, the optimal mAs is set for each body part and there is a _____ kVp increase for each cm of thickness.
2
252
With automatic exposure control the exposure is terminated when the optimum _____ is reached
OD
253
The prime factors include all of the following EXCEPT
filtration
254
The factors that directly affect x-ray quantity are
MA and time
255
If the mAs of a radiograph is increased from 10 to 20, the resulting radiograph will exhibit
increased radiographic film density.
256
The relationship between mAs and exposure is
directly proportional.
257
Kilovoltage is the primary controlling factor of
radiographic film contrast
258
An increase in kVp by 15 percent will cause an approximate ____ in the exposure/density.
doubling
259
Adjustments in kVp should be used to control radiographic
contrast
260
X-ray beam penetrability is primarily controlled by
kvp
261
All factors remaining constant, which of the following set of exposure conditions would yield an image with the GREATEST radiographic film density?
400 mA, 200 ms, 40” SID
262
Which of the following sets of exposure factors would best control involuntary motion?
500 mA, 18 ms
263
The length of the exposure time (S) for a radiograph, is used to primarily control
motion
264
Which statement is FALSE?
As mAs decreases, exposure increases.
265
The minimum change necessary to cause a visible shift in density is ____ percent of mAs
30
266
Which generator produces the least amount of radiographic density per mAs
single-phase, 2-pulse
267
Which generator produces the greatest amount of radiographic density per mAs?
high-frequency generator
268
Which rule is used as a guide to maintain the same density when kVp changes?
15% rule
269
The relationship between exposure and SID is
inversely proportional to the square of the distance
270
The principal controlling factor of contrast is
kvp
271
Factors affecting recorded detail include
focal spot size
272
If using a high-frequency x-ray generator, which of the following will have the greatest effect on INCREASING intensity?
15% increase in kVp
273
How much mAs will be generated if the control panel is set at 200 mA and 1/5 second?
40 MAS
274
At 60 kVp, how much must the kVp be increased in order to double the density of the radiograph?
9 kvp
275
When using a fixed mAs technique chart, ho much should the kVp be changed for every cm of tissue?
2 kvp
276
Who is responsible for setting an appropriate back up time
radiographer
277
Fluoroscopy was developed so that radiologists could view _____ images
dynamic
278
What is the milliamperage used during conventional fluoroscopy?
< 5 mA
279
The image intensifier improved fluoroscopy by increasing image _____.
Brightness
280
Visual acuity in the eye is greatest at the _____, where _____ are concentrated.
fovea centralis, cones
281
The _____ in the retina are stimulated by _____ light; the _____ are stimulated by _____ light
rods, low; cones, bright
282
With image intensification the light level is raised to _____ vision.
photopic
283
X-rays that exit the patient and enter the image intensifier first interact with the _____.
input phosphor
284
The input phosphor converts _____ to _____.
x-rays, light
285
The _____ in the image intensifier emits electrons when it is stimulated by light photons.
photocathode
286
The number of light photons emitted within the image intensifier is _____ to the amount of x-ray photons exiting the patient.
directly proportional
287
Electrons hit the _____ after exiting the anode.
output phosphor
288
The _____ is the product of the minification gain and the flux gain.
brightness gain
289
The ratio of x-rays incident on the input phosphor to light photons exiting the output phosphor is called
flux
290
The capability of an image intensifier to increase the illumination level of the image is called its _____.
brightness gain
291
An image intensifier tube is identified by the diameter of its _____.
input phosphor
292
Viewing the fluoroscopic image in magnification mode increases _____.
contrast resolution, spatial resolution, and patient dose.
293
Automatic brightness control (ABC) maintains the brightness of the image by varying _____.
kVp and mA
294
The time it takes to turn on the digital fluoroscopy x-ray tube and reach the selected mA and kVp is the _____ time.
interrogation
295
charge-coupled device used in digital fluoroscopy provides high _____.
detective quantum efficiency.
296
Digital fluoroscopy energy subtraction has less _____ than temporal subtraction.
motion artifact
297
Digital fluoroscopy systems with hybrid capabilities use both _____.
temporal and energy subtraction
298
Remasking may be required due to _____.
noise, motion, or technical factors
299
The combination of temporal and energy subtraction techniques is called _____.
hybrid subtraction
300
Digital fluoroscopic dose rate is lower than that for continuous analog fluoroscopy
true
301
Fluoroscopy is a ____ x-ray examination
dynamic, real-time
302
The input phosphor absorbs ____ and emits ____.
x-ray photons; light photons
303
The photocathode absorbs ____ and emits ____.
light photons; electrons
304
Electrostatic lenses are used to accelerate and focus
electrons.
305
The output screen absorbs ____ and emits ____.
electrons; light photons
306
The input screen is ____ in shape
concave
307
Fluoroscopic resolution with image intensification will vary according to
minification gain,electrostatic focal point, input and output screen diameter.
308
The edge brightness reduction problem in image intensification tubes is called
vignetting.
309
Cassette-based spot filming has been replaced by
digital photospots.
310
Digitization of the fluoroscopic image permits
image post-processing,transfer via PACS,electronic archival
311
Which is an advantage of digital fluoroscopy over conventional fluoroscopy?
Speed of image acquisition, Post processing
312
Which is an advantage of a flat panel image receptor over an image intensifier
smaller, easier to manipulative, lighter
313
The major factors effecting the amount of brightness gain in an image intensifier are:
minification gain and flux gain
314
Multifield Image Intensification produces a higher patient dose.
true
315
Hybrid subtraction can provide the highest quality digital fluoroscopy images
true
316
Patient dose is lower with conventional fluoroscopy than with digital fuoroscopy.
false
