Exam 2 Flashcards
(298 cards)
1
Q
What % change in mAs makes a visible difference in density?
A
30%
2
Q
If 5% if an incident beam is transmitted through a body part then 95% of the beam was?
A
Absorbed, scattered and also attenuated
3
Q
Principle function of grid
A
To increase radiographic contrast (because it is reducing scatter
4
Q
When scatter radiation is removed image ____ improves.
A
contrast
5
Q
The ____ protects the emulsion from scratches, pressure and contamination for relatively rough manipulation of x-ray film exposure.
A
Overcoat
6
Q
Film that has emulsion coated on both sides is called?
A
Double Emulsion
7
Q
Reduction of radiation intensity due to scattering and absorption is called…
A
Attenuation
8
Q
Maintaining density when changing from screen to a grid technique
A
Multiply mAs by the Grid Factor
9
Q
Patient does is ____ with added filtration?
A
Reduced
10
Q
What is a compensating filter?
A
Shaped aluminum slide into collimator
11
Q
The ____ is the foundation of radiographic film whose primary purpose is to provide a rigid structure on to which the emulsion can be coated.
A
Base
12
Q
When kVp and/or filtration increases, beam quality _____.
A
increases (filtration lowers PT dose)
13
Q
What kind of PT requires less radiographic technique and thin but appears to look/be healthy
A
Hyposthenic
14
Q
Photon interaction free ____ from the silver & bromide atoms in the silver halide ____..
A
Electrons Crystal
15
Q
With exposure to both x-ray and light ____ interactions occur in the emulsion.
A
photon
16
Q
A low-contrast emulsion contains ____ silver halide grains that have a wider range of sizes.
A
Larger
17
Q
What is AEC?
A
Automatic Exposure Control Proper density meets multiplier and it terminates
18
Q
Reduction of radiation intensity due to scattering and absorption is called ____.
A
Attenuation
19
Q
What focal spot provides for a shorter exposure time minimizing motion blur?
A
Large
20
Q
Base & Emulsion Diagram
A
21
Q
Original Base
A
1869 - Glass Not practical: too heavy, Breakability, Awkwardness in handling
22
Q
Quantum Mottle refers to? and is a principal contributor to what?
A
-principal contributor to radiographie noise -random nature by which x-rays interact w/image receptor
23
Q
The ____ of an x-ray beam is called x-ray quality.
A
penetrability
24
Q
If the Grid Ratio increases then OD?
A
Decreases
25
What is the relationship in the characteristic curve?
Relationship between OD & Radiation Exposure
26
Short scale contrast means
Few shades of gray, Low kVp (i.e..extremity x-ray)
27
Latitude refers to...
The range of exposures over which the IR responds with OD's in the diagnostically useful range.
28
Grid Ratio and PT Doe
Higher grid ratio, higher lead content Higher the lead content, higher the exposure factors needed Higher the exposure factors, higher the patient dose
29
What part of the image formation occurs during exposure?
Latent Image Formation
30
Grids are constructed with radiopaque ____ and radiolucent ____ materials.
Strips Interspace
31
The higher the grid ratio the better the ____ which increases \_\_\_\_.
"clean up" which increases radiographic contrast
32
Tight collimation, low kVp and PT compression increase \_\_\_\_.
contrast
33
Thicker body parts result in greater \_\_\_\_.
Attenuation
34
Too long of a scale of contrast what would you do?
Increase kVp by 15% and divide the mAs by half.
35
If the speed of the IR is doubled; what will you do maintain the density?
The mAs must be halved and no change is required in kVp
36
Base & Emulsion are two basic components of ____ \_\_\_\_.
Radiographic Film
37
What type of PT is big & overweight in frame?
Hypersthenic
38
The ____ has high subject contrast; the ____ has low subject contrast.
Chest Abdomen
39
If the thickness of the part increases then OD?
Decreases
40
If you increase kVp then OD?
Increases
41
Factors affecting film speed.
-Concentration of silver halide crystals -Thickness of emulsion -Shape -Tabular grains: flat providing, more surface area to volume ratio
42
x-rays transmitted w/out interaction and scattered (or compton interaction) radiation are called ____ \_\_\_\_ \_\_\_\_.
image forming x-rays
43
How does speed affect detail?
Faster speed results in less detail. Slower speed results in more detail.
44
Thicker body parts result in greater \_\_\_\_.
Attenuation
45
What would display the most radiographic density?
Air
46
Low Noise Accompanies....
Slow image receptors high spatial resolution high contrast resolution
47
Size of phosphor crystals thickness of phosphor layer and its composition determine screen \_\_\_\_.
characteristics
48
A x-ray beam that could pass through ____ tissue would have high penetrability & quality.
dense
49
Latitude and Contrast are ____ \_\_\_\_ and wide latitude means the mAs can what?
Inversely Proportional and mAs can vary more and still produce a diagnostic image.
50
True or False: The use of radiographic intensifying screens with film allows reduced technique and therefore reduced PT dose. However, the image is more blurred than it would be after exposure without screen.
True
51
Variable collimators are the most commonly used ____ \_\_\_\_ \_\_\_\_.
beam restricting device
52
\_\_\_\_ focal spot size is reserved for fine-detail radiography, in which the quantity of x-rays is relatively low.
Small
53
If the IR speed increases then OD?
Increases
54
How does Quantum Mottle appear on the image?
Quantum Mottle has a grainy appearance associated with using a low # of x-rays to produce
55
Main disadvantage of crossed grid
grid cut-off (orthopedic work)
56
Why is it important to keep exposure time as sure as possible?
To minimize motion blur
57
Why does an x-ray tube have 2 focal spot sizes?
Small Focal Spot - improves spatial resolution of high-contrast anatomy Large Focal Spot - useful when a high-intensity x-ray beam is required for thick anatomy.
58
To produce a long scale of contrast, a technologist would set a technique as follows
High kVp & High mAs
59
A ____ material emits light for a period of time after stimulation.
Phosphorescent
60
Tight collimation lowering kVp & PT compression increase \_\_\_\_.
contrast
61
What is the key when using a machine with AEC?
Positioning
62
What is inherent filtration?
-glass or metal envelope of x-ray tube -variable-aperture light-localizing collimator
63
Linear or Parallel Grid cleans scatter ....
in one direction - only transverse - across long axis of grid
64
High quality radiograph
faithfully reproduces structure and tissue
65
What is large focal-spot?
-generally used -assures sufficient mAs can be used thick dense part -shorter exposure: minimizes motion blur
66
Primary control for contrast is \_\_\_\_.
kVp (as kVp increases both quantity and quality of x-radiation increases so a higher portion of the primary beam reaches the image receptor)
67
Primary Control of contrast is \_\_\_\_.
kVp
68
Crossed Grid
Cleans up both directions of grid
69
What is contrast resolution?
The ability to distinguish anatomic structures of similar subject contrast.
70
What influences image receptor (film) contrast?
-contrast medium -thickness -atomic #
71
Gelatin makes up the ____ of protective covering on radiographic film.
overcoat
72
Grid Ratio
Height of grid strip divided by thickness of interspace material. H/D
73
General size & shape of a PT is referred to as?
Body Habitus
74
\_\_\_\_ filters are shapes of Al mounted onto a transparent panel that slides in the grooves beneath the collimator?
compensating filter
75
The formation of the latent image is sometimes called the ____ effect.
Photographic
76
Name 3 common factors that determine amount of scatter absorbed with a grid.
-Angle of scattered photons -Height of grid strips & width H/D -Interspace Material
77
Attenuation
Reduction in x-ray intensity that results from absorption & scattering
78
Types of secondary radiation (2)
Scatter Radiation Leakage Radiation
79
The least dense body tissue is...
Fat
80
What is differential absorption?
Different degrees of absorption in different tissues that result in image contrast and formation of the x-ray image.
81
What subject factors attenuate the x-ray?
Chunky Parts & Parts with High Atomic Number (chunky + high atomic # = no remnant x-rays on the IR)
82
Film Contrast
characteristic inherent in film itself to emphasize high for low contrast imaging
83
When radiograph is over penetrated what happens?
Trabecular "burned out"
84
True our False kVp is the most important influence of film contrast.
True
85
Fast Image Receptors have...
High Noise Low Spatial Resolution Low Contrast Resolution
86
A radiographic can be adequately penetrated yet....
still be under or overexposed
87
How many components does radiographic noise have and what are their names?
4 components: film graininess structure mottle quantum mottle scatter radiation
88
Speed, contrast and sensitivity of screen film is determined by what 3 factors?
size, shape and distribution of silver halide crystals
89
If you increase SID then OD?
Decreases
90
Air gap technique
for trauma scatter goes in opposite direction
91
Grid surface x-ray absorption formula
% x-ray absorption width of grid strip / width of grid strip + width of grid interspace x 100
92
Properly exposed radiographs take place where? (Amounts?)
Straight Line Portion \*Intermediate Levels 0.25 to 2.5 (a bit higher for mammo.)
93
Image Quality
The fidelity with which the anatomical structure that is being examined is rendered on the radiograph.
94
Density can be measured using a \_\_\_\_.
Densitometer
95
SHALL
Short Scale High contrast (low kVp B&W) Long scale Low contrast (high kVp Gray)
96
When mAs increases ____ increases
density
97
Cellulose Triacetate
-Same characteristics, not as flammable -Did not store well for long periods -Fire resistant, when burned releases nitrogen dioxide, a poisonous gas
98
Safelight
Red can be used for green or blue sensitive film.
99
The most dense body tissue is...
Bone
100
Short scale of contrast means you would?
decrease kVp 15% & double the mAs
101
The ____ layer adds to the light efficiency of intensifying screens.
Reflective
102
\_\_\_\_ makes anatomy more visible.
Contrast
103
Cellulose Nitrate
-1st lightweight base -Developed WWI -Extremely flammable -Hospital fire's -1930 cleveland hospital (150 ppl killed started in storage area
104
If the developing time increases then OD?
Increases
105
What is the velocity of all electromagnetic radiation?
3 x 10-8 m/s
106
\_\_\_\_ ____ holds the silver halide crystals.
Gelatin Emulsion
107
2 terms that can be used for spatial resolution
Detail & Recorded Detail
108
Grid Frequency
of grid strips or lines per inch
109
When kVp increases ____ increases
density
110
What is attenuation?
Reduction in energy of beam.
111
Advantages of moving grids
blurs out grid lines; moves fast enough to clean page w/out lines on image
112
A high-contrast emulsion contains ____ silver halide grains with a relatively uniform grain size.
Smaller
113
Factors that affect film contrast
-silver halide crystals size shape and distribution -High Contrast Emulsion: Small crystals, uniform size -Low Contrast Emulsion: Large crystals, wider range of sizes (shades of gray)
114
Beam quality is measured by ____ \_\_\_\_ \_\_\_\_.
Half Value Layer/Filtration
115
Size of phosphor crystals, thickness of phosphor layer & its composition determine screen \_\_\_\_.
characteristics
116
Radiographic Contrast is a product of what 2 factors.
Image Receptor Contrast Subject Contrast
117
Name the factors that control/affect detail?
Film Speed Focal Spot Size SID OID Motion Distortion
118
Grid use increases ____ and decreases.
unwanted, non-diagnostic density contrast
119
Variable collimators are the most commonly used?
Beam Restricting Device
120
Do filters have an affect on density?
Yes, it filters out the low energy photon therefore density is increased.
121
Focusing distance is associated with which of the following?
Grids (Focusing distance or Focal Range is used to specify optimal OD)
122
Formula for maintaining density from one grid to another
old mAs/new mAs = oldGF/newGF
123
Film Resolution
-ability to image an object faithfully -measured in line pairs per mm
124
\_\_\_\_ contrast film contains smaller crystals of uniform size.
High
125
Positive Beam Limiting
Feature of radiographic collimators that automatically adjusts the radiation field to the size of the image receptor.
126
Unexposed x-ray film that has been processed appears _____ and easily transmits _____ but not \_\_\_\_\_.
Lucent Light Not Images
127
Speed
Ability of an image receptor to respond to low x-ray exposure.
128
High kVp/mAs produces
low contrast long scale, many shades gray wide latitude
129
A parallel grid's main disadvantage is \_\_\_\_.
Grid cut-off
130
The thicker the PT the more x-radiation is required to penetrate the PT exposure and for this reason the Rad Tech. must use ____ to measure the thickness.
Calipers
131
An ____ \_\_\_\_ is an example of both luminescence & fluorescence.
Intensifying screen
132
Sensitometry
Study of the relationship between the: -intensity of exposure of the film and the -blackness after processing
133
Image with high number of x-rays will have ____ quantum mottle.
Lower
134
How does beam limitation affect density?
It reduces the density and the amount of scatter.
135
Use of collimation ____ contrast and ____ PT dose.
improves reduces
136
The only x-rays transmitted through a grid are those ......
traveling in the direction of the interspace. X-rays scattered obliquely through the interspace are absorbed.
137
What happens to PT dose when kVp is increased?
It is reduced
138
Subject (PT) Factors
Selection of radiographic technique that properly compensates for PT's size, shape and tissue composition.
139
Speed, contrast and sensitivity of screen-film is determined by what 3 factors?
The size, shape and distribution of silver halide crystals.
140
Aluminum or plastic make up the ____ in grids.
Interspace material
141
What is added filtration?
Inserted into the collimator.
142
When scatter radiation is removed image ____ improves.
contrast
143
Lowering kVp ____ PT dose and image contrast.
will increase
144
\_\_\_\_ is the sensitivity of the screen-film combo to x-rays and light.
Speed
145
What are the two main parts of sensitometry used to describe characteristic curve?
1.) Exposure to the film. 2.) % of light transmitted through the processed film
146
The purpose of a filter is to ____ \_\_\_\_ \_\_\_\_.
Reduce PT Dose
147
Focal-Spot sizes and values
Small 0.5mm, 0.6mm Large 1.0mm, 1.3mm
148
Biggest enemy of radiographic contrast is?
Scatter or Fog
149
Grid cleans up what?
scatter
150
Grids are constricted with radiopaque ____ & radiolucent ___ materials.
Radiopaque Strips Radiolucent Interspace
151
Gelatin makes up the ____ of protective covering on Radiograph film.
overcoat
152
A radiograph that has small differences in OD are ____ \_\_\_\_ radiographs.
low contrast
153
If you increase mAs then OD?
Increases
154
Manifest Image
Processed image (aka latent image)
155
Contrast Resolution
Ability to distinguish anatomical structures of similar subject contrast ie. Liver/Spleen or Gray Matter/White Matter
156
Less Grid Frequency translate to
more distinct grid lines on film
157
When OD is out side the diagnostic range what is lost? and why?
Contrast, because the image is in the "Toe" or "Shoulder" of the characteristic curve.
158
A term borrowed from electrical engineering is called...
noise
159
Resolution
The ability to image 2 separate objects and visually distinguish one from the other.
160
If the Mass Density increases then the OD?
Decreases
161
Radiographic Contrast = ____ x \_\_\_\_
Image Receptor Contrast x Subject Contrast
162
Screens Spectral Matching
-Calcium Tungstate emits blue or blue violet -Exposed w/ silver halide film -Rare earth - green sensitive film (orthochromatic film) -Colors not matched: speed of system greatly reduced increased PT dose
163
Phosphorescence
Phosphor continues to emit light after stimulation.
164
Which of the following is most likely to result from the intro. of a grid to a particular exam?
Increased PT does and Increased Contrast
165
Contrast is the degree of difference in ____ between areas of an image.
Optical Density
166
What factors the visibility of detail?
Image contrast and Optical density
167
Image with low number of x-rays will have ____ quantum mottle.
Higher
168
An x-ray beam that could pass through ____ tissue would have high penetrability & quality.
dense
169
Name 2 important characteristics of radiographic film base.
lucency dimensional stability
170
High Spatial Resolution and High Contrast Resolution require?
Low Noise and Slow Image Receptors
171
In the 1950's a stronger and thinner film base was introduced. What material was this film base made of?
Polyester
172
What improves as screen blur decreases, motion blur decreases and geometric blur decreases?
Spatial Resolution
173
\_\_\_\_ are designed to remove scattered x-rays before they reach the IR?
Grids
174
Rule for Grid Use
Use for parts 8cm and up smaller? no grid larger? grid shoulder or knee optional
175
4 Subject Factors for OD & Contrast
Thickness of the part Density of the part Atomic # of the part Motion
176
What is between the emulsion and the base of radiographic film that holds it together during the process?
Adhesive Layer
177
The body tissue with the highest absorption...
Bone
178
An ____ \_\_\_\_ is an example of both luminescence and fluorescence,
Intensifying screen
179
An increase of 15% in kVp is equivalent to increasing mAs by \_\_\_\_.
Double (100% increase)
180
Focused grid is designed to
minimize grid cut-off
181
Film base can maintain its size and shape during use and processing so that it doesn't contribute to image distortion. This characteristic is best defined as ____ stability.
Dimensional
182
A radiograph can be under or over penetrated yet still...
have adequate density
183
Quantum mottle is similar to the \_\_\_\_.
sowing seeds of grass
184
Latent Image
Unprocessed but exposed (photoelectric effect)
185
Grid strips height divided by width (distance) of interspace determines ____ \_\_\_\_.
Grid Ratio
186
What is small focal-spot size for?
Fine Detail (x-ray quantity low)
187
mAs =
#of photons
188
\_\_\_\_ ____ holds the silver halide crystals.
Gelatin Emulsion
189
True or False
High contrast is also known as a short scale of contrast, which produces an image composed with more B&W's and not as many shades of gray.
True
190
What when raised increases the penetrating quality of the central ray?
Filtration and kVp (Both)
191
Photons interactions free ____ from the silver and bromide atoms in the silver halide \_\_\_\_.
electrons crystal
192
Exposed processed x-ray film can be \_\_\_\_.
Opaque
193
What focal spot provides for a shorter exposure time minimizing motion blur?
Large
194
x-rays transmitted without interaction & scatter (or compton interaction) radiation care called \_\_\_\_.
Image forming x-rays
195
Film Contrast
Characteristic inherent in film itself to emphasize high or low contrast imaging.
196
Disadvantages of moving grids
bulky, complicated subject to failure increases OFD poor design can cause motion longer minimum exposure time advantages outweigh disadvantages
197
Most x-ray tubes are equipped with two?
focal spots sizes
198
After photons interact releasing negatively charged e` where do these e` migrate to?
Sensitivity Center
199
Contrast
Differences in Optical Density (degree of diff btw the light and dark areas of a radiograph)
200
Name two important characteristics of radiographic film base.
lucency & dimensional stability
201
When an image is under penetrated what happens?
Trabeculae "whited out"
202
Because of the anode heel affect density is less @ which end of the x-ray beam?
Anode
203
Radiographic Contrast is the product of ____ contrast & ____ contrast.
Image Receptor Subject
204
2 basic parts of Radiographic Film
Base and Emulsion
205
PT does is increased with a ____ in kVp.
Decrease
206
The effects described as differential absorption are?
1) Responsible for radiographic contrast 2) Result of attenuating char. of tissue. 3) Minimized by using High kVp
207
The ____ of an x-ray beam is called x-ray quality. (HVL decrease total # of x-rays)
penetrability
208
Properly exposed film appears ____ and heavily exposed film appears \_\_\_\_.
with various shades of gray black
209
A radiograph that has marked differences in OD is a ____ \_\_\_\_ radiograph.
high contrast
210
To produce a long scale of contrast, a technologist would set a technique as follows:
High kVp and High mAs
211
Speed of the image receptor is ____ but it very much influences \_\_\_\_.
Not apparent on the radiographic image Resolution and Noise
212
Factors Affecting Film Speed
-Thickness of the emulsion -Concentration of Silver Halide Crystals -Shape--\>used to be fate 3 dimensional then changed to--\> -Tabular Grains -flat providing more surface area and volume ratio
213
What controls PT radiation dose?
mA (or x-ray quantity)
214
High spatial resolution and high contrast resolution require?
Low Noise & Slow Image Receptors
215
Off-Level Grid
Grid not perp. to CR x-rays abnormally angulated grid cut-off across entire radiograph reduced density
216
kVp is the primary control of ____ & \_\_\_\_
x-ray beam quality and beam penetrability
217
A technologist is standing next to a portable examination of the abdomen at 50" and receives 3rem. The image is of poor quality and the technologist must return to repeat the exam. This time he stands at 70" what is the rem now?
I1/I2 = (D2/D1)2
3/x = (70/50)2
3/x = 4900/2500
4900x = 7500
x = 7500/4900
x = 1.53 rem
218
The emulsion consists of a homogenous mixture of ____ & \_\_\_\_.`
Gelatin and Silver Halide Crystals
219
One difference between large & small focal spots is the \_\_\_\_\_?
capacity to produce x-rays
220
Name 3 common factors that determine amount of scatter absorbed with a grid.
Angle of scattered photons. Height of grid strips. Width of interspace material.
221
Almost 99% of latent image is created by ____ from the screens.
Light
222
Velocity of Light is constant and symbolized?
3 x 10-8 m/s
223
When raised ____ & ____ increases the penetrating quality of the central ray.
Filtration & kVp
224
What part of the image formation occurs during exposure?
Latent Image Formation
225
Grid Material
Lead
226
Developing stage
stage of processing during which the latent image is converted to a manifest or visible image
227
What is the primary controlling factor for contrast?
kVp
228
mAs controls
Optical Density
229
Polyester
-Introduced in 1950 -Thinner, stronger, more fire resistant, less toxic -Stronger than cellulose triacetate -Stands up to processing, handling, and storage better
230
Silver bromide and silver iodide make up the ____ in film emulsion.
Crystals Bromide 98% Iodide 2%
231
Grid Purpose
-designed to transmit x-rays whose direction if on line from source (primary) -x-rays at an angle (scattered) are absorbed by grid materials -decreases scatter to the film -principle function to increase radiographic contrast
232
Radiographic noise is ...
the random fluctuation in the OD of the image
233
What effect does doubling the SID have on density?
Density will be reduced by 1/4
234
Subject Contrast
Determined by the size, shape and x-ray attenuating characteristics of the anatomy being examined & energy (kVp)
235
On a focused grid grid strips are placed
at angle = primary beam
236
\_\_\_\_ contrast film contains smaller crystals of uniform size.
High
237
If the collimation increases then OD?
Decreases
238
Radiographic Film contains OD's that range from ____ to \_\_\_\_.
0 Clear/Lucent (unexposed/ processed film transmits light not images) 4 Black/Opaque (processed exposed)
239
kVp & mAs directly affect
density
240
What is the most common error when grid cut off appears across the image?
grid is off-level
241
Together the filtering effect of the x-ray tube's glass envelope and its oil coolant are referred to as? (3 forms)
Inherent Filtration (.5 mm Al) Added Filtration (1 mm Al) Compensating Filtration (1 mm Al) (2.5 mm Al)
242
How does kVp relate to differential absorption?
Higher kVp will allow more photons to transfer through.
243
What has the greatest effect on contrast?
kVp
244
Grid Covering
thin aluminum casing
245
Primary control of OD is \_\_\_\_.
mAs (as mAs increases radiation quantity increases therefore the # of x-rays @ the image receptor increases for higher OD)
246
Main disadvantage of parallel grid
grid cut-off (have to use correct SID)
247
4 Film Factors
-Density or OD -Contrast (depends on kVp) -Speed (film screen mostly) -Latitude
248
How does filtration affect the primary beam?
It increases the average energy of the primary beam.
249
Silver Bromide & Silver Iodide make up the ____ in film emulsion.
Silver Halide Crystals
250
Types of moving grid mechanisms include (2)
Reciprocating and Oscillating
251
\_\_\_\_ are designed to remove scattered x-rays B4 they reach the IR.
Grids
252
The ____ beam refers to the x-rays that remain as the useful beam exits the PT. It consists of x-rays scattered away from the IR and image forming IR.
Exit
253
Sthenic
Strong or Active
254
With exposure to both x-ray & light ____ interaction occurs on the emulsion?
Photon
255
Spatial Resolution
Ability to image small objects that have high subject contrast (bone-soft tissue interface)
256
Examples of Low, Moderate and High Contrast
Low - Abdomen Moderate - Elbow (Fat Pads) High - Hand
257
What recess motion blur?
short exposure time
258
\_\_\_\_ is the most critical consideration when using a crossed grid.
alignment
259
If the x-ray is totally absorbed its interaction is \_\_\_\_.
Photoelectric
260
Because of WWI something needed to change in the acquisition of images in diagnostic imaging \_\_\_\_.
Radiographic Film was developed
261
Most important characteristics of radiographic image quality are?
Spatial Resolution Contrast Resolution Noise Artifacts
262
Contrast is the degree of difference in ____ \_\_\_\_ between areas of an image.
Optical Density
263
A group of atomic silver is called a?
Latent Image Center
264
3 types of x-ray filtration are?
Inherent Added Compensating 2.5mm Al
265
OD has a ____ \_\_\_\_ ____ that can be calculated if?
Precise Numeric Value If the level of light incident on a processed ilm and the level of light transmitted through that film are measured
266
Beam quality is affected by\_\_\_\_.
kvP and Filtration
267
The degree of blackening of the x-ray image is \_\_\_\_.
Density
268
Base & emulsion are 2 basic components of \_\_\_\_.
Radiographic Film
269
Latitude can be thought of as...
the margin of error for technical factors
270
A ____ material emits light for a period of time after stimulation.
phosphorescent
271
In the toe and shoulder of characteristic curve large variations in ____ result in a small change to \_\_\_\_.
exposure OD
272
Aluminum or plastic make-up the ____ in grids.
Interspace Material
273
Fluorescence
Visible Light is only emitted while the phosphor is stimulated.
274
kVp in relation to density is not...
linear
275
Grid strips height divided by width (distance) of interspace material determines \_\_\_\_.
Grid Ratio
276
How does kVp control OD?
Helps determine the # of x-rays (in the image forming beam) hence the average OD
277
\_\_\_\_ is the material with which x-rays or light photons from intensifying screens interact and transfer information.
Emulsion
278
The image forming x-rays include those which have been...
remnant and scatter
279
What happens to PT does when kVp is increased?
Reduced
280
Spatial Resolution improves as....does what?
Motion, Screen, Geometric blur DECREASE
281
On a focused grid grid strips are placed
at angle = primary beam
282
Thermionic Emission at the filament creates a?
space charge
283
Almost 99% of latent image is created by ____ from the screen.
Light
284
Emulsion is enclosed by a protective covering of gelatin called \_\_\_\_.
Overcoat
285
PT dose is ____ w/ added filtration
Reduced
286
Biggest enemy of Radiographic Contrast?
Scatter or Fog
287
When kVp and/or filtration increases beam quality \_\_\_\_.
increases
288
The ____ layer adds to the light emitting efficiency of intensifying screens.
Reflective
289
What is the controlling factor of density?
mAs
290
Image Receptor Contrast
Inherent in the screen-film combo. and is influenced somewhat by processing of the film.
291
When the grid frequency is higher it....
allows more to be captured
292
High kVp results in reduced ____ \_\_\_\_
image contrast
293
Grid interspace material can be made of ____ or \_\_\_\_.
Plastic (most often) Aluminum
294
\_\_\_\_ ensures the x-ray beam is collimated to the IR size.
Positive beam limiting device
295
True or False The size and concentration of silver halide crystals primarily affect film speed.
True
296
\_\_\_\_ makes up the base of radiographic film.
polyester
297
The ____ principle function is to provide mechanical support for silver halide crystals by holding them uniformly dispersed in place.
Gelatin's
298
Which grid ratio is generally for portable is
6:1
