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Raad 354 - Physics > SG1 > Flashcards

SG1 Flashcards

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1
Q

Increased visibility of details is a pros of ___ kVp

A

Variable

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2
Q

Decreased patient dose is a pros for ___ kVp

A

Fixed

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3
Q

Increased consistent of IR EXPOSURE is a pros of ___ kVp

A

Fixed

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4
Q

Small increments change in exposure to compensate for body parts is a pros for ___ kVp

A

Variable

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5
Q

Lengthen exposure latitude is a pro for ___ kVp

A

Fixed

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6
Q

Increased contrast images is a pros for ___ kVp

A

Variable

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7
Q

Increased resolution is a pro for ___ kVp

A

Variable

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8
Q

Decreased xray tube wear is a pro for___ kVp

A

Fixed

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9
Q

Decreased patient motion & time settings are pros for ___ kVp

A

Fixed

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10
Q

Which of the following is/are cons for fixed kVp
A. More scatter
B. Increased image contrast
C. Decreased image contrast
D. Increased tube wear
E. A & B
F. A & C
G. C & D

A

F- more scatter and decreased contrast

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11
Q

What are the pros for FIXED kVp (6)

A
  1. Decreased dose
  2. More image information
  3. Increased consistent IR exposure
  4. Lengthen exposure latitude
  5. Decreased xray tube wear
  6. Decreased time setting & pt motion
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12
Q

Which of the following are pros for VARIABLE kVp?
A. Decreased contrast
B. Increase contrast
C. Increase resolution
D. Decrease resolution
E. A & D
F. B & C

A

F. - increase contrast & resolution

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13
Q

What does a fixed kVp provide?

A
  1. Uniform contrast
    2.easily remembered kV series to add mAs
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14
Q

To achieve an appropriate image, what is being kept constant, and what is varied

A

Constant - kVp
Varied - mAs

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15
Q

Technique factors function best when ___

A

LARGE # being kept constant while a SINGLE factor is varied

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16
Q

What is the goal of exposure systems

A

Provide method of consistency in quality of images

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17
Q

Variables of exposure systems changes to ___

A

Thickness of body part

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18
Q

What required that the technical factors for each exposure be recorded, regardless of whether the image is within acceptance limits

A

Fine- tuning

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19
Q

Variable mAs system depend on ___ (2)

A

IR Exposure & body thickness

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20
Q

To establish a variable kVp system, what are the three criteria?

A
  1. All contrast is acceptable
  2. Small-part size kVp provide adequate penetration
  3. Large-part size kVp avoid xs scatter fog
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21
Q

Small-part size kVp ____
A. Provide Adequate penetration
B. Avoid excess scatter fog

A

A

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22
Q

Large-part size kVp ____
A. Provide Adequate penetration
B. Avoid excess scatter fog

A

B

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23
Q

What component within AEC measured exposure to IR?

A

Ionization chamber

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24
Q

What does ionization chamber controlled?
A. Contrast
B. IR Exposure
C. Brightness
D. Kvp

A

B

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25
Q

What eliminate the radiographer’s need to set mAs

A

AEC

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26
Q

What is direct action

A

ionizing particles interact directly with macromolecules (DNA) = inactive or functionally altered

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27
Q

Is direct or indirect action more common? Why?

A

Indirect –> water more abundant
Direct –> random 1% chance

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28
Q

Effects of direct action

A

direct energy exchange to DNA = DSB/SSB = apoptosis

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29
Q

What is indirect action

A

radiolysis of water (breakdown of water from radiation)

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30
Q

How does indirect action occur

A

x-ray interacts with water = ionization = breaks apart = free radicals –> secondary radiation

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31
Q

What is a free radical

A

atom with single unpaired electron

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32
Q

Characteristic of free radical

A

Highly reactive
short life span (1millisecond)
causes cell death

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33
Q

Ways free radicals causes damage

A

ionization
excitation
creation of toxic substances –> peroxide and superoxide

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34
Q

What is high LET associated with? Is damage repairable?

A

direct action –> DSB
Repairable? unlikely

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35
Q

What is low LET associated with? Is damage repairable?

A

point mutation
Repairable? yes –> action of repair enzymes

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36
Q

What is non-threshold relationship

A

any radiation dose has the capability of producing a biologic effect

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37
Q

What is threshold relationship

A

below a certain radiation level or dose, no biologic effects are observed

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38
Q

Which relationship best fits
“No radiation dose can be considered absolutely safe”

A

non-threshold

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39
Q

List cellular effects of irradiation (7)

A

instant death
reproductive death
apoptosis
mitotic death
mitotic delay
Permanent or temporary interference with function
Chromosome breakage

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40
Q

What causes cellular effects of irradiation

A

Type of cell reaction from amount of transferred energy to cell’s nucleus

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41
Q

Instant death

A

given 1000+Gy/s, disrupts cellular form, structure, and chemistry

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42
Q

Reproductive death

A

given 1-10Gy

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43
Q

What does AEC permits?

A

adjustment of radiation amount to send termination signal

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44
Q

Many ionization chambers are activated to control_____

A

exposure

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45
Q

which component of the ionization chamber terminate exposure when appropriate Voltage reached

A

operation amplifier

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46
Q

to establish exposure system, a variety of technical factor combinations are used, but which factor is being kept the same?
a. mAs
b. kVp

A

mAs

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47
Q

___kVp provide uniform contrast and easily remembered kV series to add mAs
a. fixed
b. varied
c. optimal

A

FIXED

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48
Q

What does optimal kVp produce?

A

lower contrast and minimum patient exposure

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49
Q

What is the objective to establish optimal kVp

A

determine highest kVp and lowest contrast within acceptable limits

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50
Q

What should be avoided near chamber location for AEC?

A

too tight and too wide collimation

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51
Q

Why avoid tight collimation near chamber location of AEC

A

to avoid overexposed image since the chamber will mistake the tissue to be extremely dense

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52
Q

Why avoid wide collimation near chamber location of AEC

A

avoid underexposed image since wide collimation results in scatter radiation, causing AEC to terminate early

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53
Q

Which of the following will result in underexposed image?
a. tight collimation
b. wide collimation
c. too short back-up timer
d. too long back-up timer
e. A & B
f. B & C
g. A & D

A

F - wide collimation & too short timer

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54
Q

Which of the following will result in overexposed image?
a. tight collimation
b. wide collimation

A

A

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55
Q

Which AEC component can prevent overexposure

A

back-up timer

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56
Q

How much % is anticipated manual exposure time?

A

150

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57
Q

Because displayed images do not proved any visual cues of overexposure, manufacturers developed:
a. Rescaling
b.Target Exposure
c. Deviation Index
d. Exposure Indicators

A

Exposure Indicators

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58
Q

The Target Exposure Indicator is derived from the:

a. Pixel Value
b. Log of Median
c. Speed Class
d. Look Up Table (LUT)

A

a. Pixel Value

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59
Q

What does exposure indicator represent?
a. LUT
b. speed class
c. IR exposure

A

C - IR exposure

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60
Q

high EI = ____ exposure
low EI = ____ exposure

A

excess
insufficient

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61
Q

Target EI represents _____ at ____ for specific ____

A

exposure
IR
speed class

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62
Q

______ can be used by all manufactures regardless of their specific method for calculating EI

A

deviation index

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63
Q

what is the unit for DI?

A

microgray

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64
Q

microgray unit must be included in ____

A

dicom header

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65
Q

What information must be included in DICOM HEADER for every image

A
  1. DI readout
  2. EI delivered (in microgray)
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66
Q

What can lead to a corrupted DI and EI

A

errors in histogram analysis

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67
Q

Can a corrupted EI cause corrupted DI readout?

A

yes

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68
Q

Deviation Index is ____
a. direct measurement of patient dose
b. direct indicator of IR dose
c. direct measurement of IR dose

A

B - direct indicator of IR dose

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69
Q

Which of the following can be roughly extrapolated (estimated)?
a. IR dose
b. pt dose

A

B - pt dose

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70
Q

What are the factors that can raise or lower the deviation index (4)

A
  1. poor collimation
  2. unusual body habitus
  3. presence of prosthetic device
  4. presence of gonadal shielding
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71
Q

What does speed class express

A

its sensitivity to radiation exposure

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72
Q

what made up of speed class

A

inherent speed of IR & digital processing speed

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73
Q

When is inherent speed important

A

at the image acquisition state

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74
Q

which speed class assume average exposure of 20 microgray?
a. 100
b. 200
c. 400

A

100

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75
Q

which speed class has remnant xray beam exposure at 10 microgray
a. 100
b. 200
c. 400

A

200

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76
Q

which speed class has remnant xray beam exposure at 5 microgray
a. 100
b. 200
c. 400

A

400

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77
Q

What is the speed class manufacture usually set to reduce chance of quantum mottle
a. 100
b. 200
c. 400

A

200

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78
Q

An underexposed image will have a DI ___
a. less than -1
b. more than 1
c. less than 0

A

A - less than -1

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79
Q

An underexposed image should not be repeated unless:
a. radiologist finds unacceptable amount of mottle present
b. saturation present
c. supervising technologist tells u to repeat
d. exposure indicator number indicated underexposed

A

a. radiologist finds unacceptable amount of mottle present

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80
Q

An overexposed image should not be repeated unless:
a. The radiologist finds an unacceptable amount of mottle present

b. When the lead technologist tells you to repeat it

c. When saturation occurs and there is a loss of data

d. The exposure indicator number indicates an overexposure

A

c. When saturation occurs and there is a loss of data

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81
Q

overexposed images can be fixed through ____

A

windowing

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82
Q

how do you tell if an image is over-processed but not saturated

A

if details can be seen in dark portions of the image

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83
Q

an electrical phenomenon that occurs at the detector when the dexels in a particular area have reached the maximum electrical charge that they can store is termed:
a. saturation
b. overexposure
c. underexposure
d. quantum mottle

A

A - saturation

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84
Q

Nearly all DR & CR machines can operated at a speed class of 350-400 without the appearance of ____
a. substantial saturation
b. substantial mottle
c. distortion
d. spatial resolution

A

B

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85
Q

What does saturation represent

A

complete loss of data

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86
Q

Where and when does saturation occur

A

where - at detector
when - dexels reach maximum electrical charge they can store

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87
Q

why further increase in exposure cannot be measured?

A

all dexels reach max electrical charge AND tissues display as pitch black

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88
Q

Is true saturation often occur?

A

no

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89
Q

why true saturation is rare occurence

A

bc it requires 10 times normal radiographic technique

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90
Q

A deviation index of 3.0 would show:
a. 26% overexposure
b. 100% overexposure
c. 63% of target exposure
d. 59% overexposure

A

100% exposure

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91
Q

A deviation index of 1.0 would show:
a. 26% overexposure
b. 100% overexposure
c. 50% of target exposure
d. 59% overexposure

A

a. 26% overexposure

92
Q

A deviation index of -1 would show:
a. 100% underexposure
b. 50% underexposure
c. 63% underexposure

A

B - 50% underexposure

93
Q

Which exposure indicators would be repeated if radiologist dictates?
a. +1 to +3
b. greater than 3
c. -1 to -3
d. less than -3
e. -0.5 to + 0.5

A

c. -1 to -3

94
Q

Which exposure indicators would not need to be repeated unless saturation occur?
a. +1 to +3
b. greater than 3
c. -1 to -3
d. less than -3
e. -0.5 to + 0.5

A

A & B

95
Q

Which exposure indicators would describe the target range?
a. +1 to +3
b. greater than 3
c. -1 to -3
d. less than -3
e. -0.5 to + 0.5

A

E -0.5 to + 0.5

96
Q

The image quality of grayscale/contrast is mainly controlled by:

a. Look Up Table (LUT)
b. mAs
c. Rescaling
d. kVp

A

a. Look Up Table (LUT)

97
Q

The image quality of brightness/ density is mainly controlled by:

a. Look Up Table (LUT)
b. mAs
c. Rescaling
d. kVp

A

c. Rescaling

98
Q

The image quality of sharpness(Spatial resolution) is mainly controlled by:

a. Look Up Table (LUT)
b. matrix size
c. pixel size
d. kVp

A

c. pixel size

99
Q

The image quality of magnification is mainly controlled by:

a. Field of View
b. matrix size
c. pixel size
d. part alignment

A

A & B

100
Q

The image quality of shape distortion is mainly controlled by:

a. part alignment
b. matrix size
c. pixel size
d. kVp

A

a. part alignment

101
Q

Apoptosis

A

cell death without dividing → with or without radiation

102
Q

Mitotic death

A

cell die after 1 or 2 divisions

103
Q

Mitotic delay

A

given 0.01Gy → cell failed to divide in time

104
Q

Chromosome breakage

A

loss of genetic material leads to mutation from radiation interacting with DNA

105
Q

What is Skin Erythema Dose (SED)

A

amount of radiation given caused diffuse redness over an area of skin

106
Q

What was SED used for?

A

1900-1930 Used to determine radiation exposure but was inaccurate → reaction varied by person

107
Q

What is tolerance dose also known as?

A

Threshold dose

108
Q

What is tolerance dose

A

continuous radiation dose in occupational workers without any apparent harmful acute effects

109
Q

What was tolerance dose used for?

A

Used in 1930 to measure exposure in air (Roentgen)

110
Q

When would a dosimeter be required to be worn?

A

Receiving 10% or more of annual limit of 5rem (50mSv)

111
Q

Types of dosimeters?

A

Personnel
Area monitoring

112
Q

Types of personnel dosimeters (4)

A

Optically stimulated luminescence dosimeters (OSL)
Film badges
Thermoluminescent dosimeters (TLDs)
Pocket ionization chambers

113
Q

Optically stimulated luminescence dosimeters (OSL)
Pro? (5)
Con? (1)

A

Pro: lightweight, easy to carry, not affected by heat, moisture or pressure
Con: can only monitor area if worn

113
Q

Film badges
Pro? (2)
Con? (1)

A

Pro: film is legal document of radiation exposure and can differentiate between different types of radiation
Con: heat + moisture can cause fogging over time

114
Q

Thermoluminescent dosimeters (TLDs)
Pro? (4)
Con? (2)

A

Pro: monitors dose accurately, humidity, pressure and is unaffected by temperature
Con: expensive and can only be read once

115
Q

Pocket ionization chambers
Pro? (4)
Con? (2)

A

Pro: immediate exposure readings, compact, convenient and easy to carry
Con: most expensive, can give inaccurate readings if not read everyday

116
Q

Which type of personnel dosimeter is the most sensitive?
A. OSL
B. Film badges
C. TLDs
D. Pocket ionization chambers

A

D. Pocket ionization chambers

117
Q

Which of the following is true of proper dosimeter wear?
A. It is mandatory to wear your dosimeter when working
B. Dosimeters can be worn under a jacket
C. When wearing a lead apron it can be worn under the apron on the collar area
D. Always keep your dosimeter at the workplace and never bring to another institution

A

D

118
Q

How much radiation exposure should a pregnant technologist recieve?

A

0.5mSv/month

119
Q

Types of area monitoring detector

A

Ionization chamber-type survey meter (cutie pie)
proportional counter
geiger-muller detector

120
Q

How does area monitoring instruments work?

A

responds to radiation interacting with and ionizing gas (air)

121
Q

Pros to radiation survey instruments for area monitoring (5)

A

portable
durable/reliable
interacts with radiation similar to human tissue
detects all types of radiation
cost effective

122
Q

Law of Bergonie and Tribondeau

A

Radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation

123
Q

The more a cell reproduces/divides the more _______

A

Radiosensitive the cell is

124
Q

What type of somatic effect is an acute radiation syndrome

A

early deterministic somatic effect

125
Q

How does acute radiation syndrome occur

A

when given large doses of radiation in a short period of time

126
Q

4 stages of acute radiation syndrome in order

A

Prodromal → latent → manifest illness → recovery or death

127
Q

Syndromes that contribute to acute radiation syndrome

A

hematopoietic
gastrointestinal
cerebrovascular

128
Q

Stochastic effect

A

probability that the effect happens depends on received dose but severity of effect does not

129
Q

Deterministic effect

A

both probability and severity are dependent on dose

130
Q

Examples of stochastic and deterministic

A

stochastic: carcinogenesis and embryologic effects (birth defects)
deterministic: cataractogenesis

131
Q

AAPM position on gonadal and fetal shielding

A

Support ending shielding specifically during abdominal and pelvic radiography because it can increase repeat exposure risk

132
Q

Pros of a fixed kVp chart (6)

A

decrease patient dose
gives more image information
increase consistency of IR exposure
lengthens exposure latitude
reduces xray tube wear
decrease time settings/patient motion

133
Q

Cons of a fixed kVp chart (2)

A

more scatter
lower contrast

134
Q

Pros of variable kVp system (5)

A

allows small changes in exposure to compensate for body part thickness variations
finer adjustments settings than mAs
higher contrast image
enhances visibility fine details
increases resolution

135
Q

what is AEC and what does it stand for?

A

Uses ionization chambers to measure exposure to IR
Automatic exposure controls

136
Q

Pros of AEC (2)

A

Eliminating need to set exposure time (mAs)
mA and kVp can still be set manually

137
Q

What is the structure of LCD monitor

A

front glass –> polarizing film –> color filter –> liquid crystal –> polarizing film –> back light

138
Q

What is the material of the thin layer liquid crystal

A

hydrogenated amorphous silicon

139
Q

What does the polarizing glass include to conduct electricity?

A

flat wires

140
Q

Which workstation has higher-resolution monitor?
a. display
b. diagnostic

A

b. diagnostic

141
Q

Which workstation can save changes into picture archive & PACs?
a. display
b. diagnostic

A

a. display

142
Q

What can pass through polarizing lens?

A

light waves with electrical component parallel to molecular chains

143
Q

What cannot pass through polarizing lens? Why?

A

Xray because its electrical component is perpendicular to its magnetic component

144
Q

What orientation of polarizing lens will block all light from passing through?
a. 2 lens parallel
b. 2 lens perpendicular

A

B

145
Q

What is the arrangement used to construct LCD monitor screen?
a. iodine chain molecules perpendicular to each other
b. iodine chain molecules parallel to each other

A

A

146
Q

Which component is in between 2 polarizing lens?
a. front glass
b. liquid crystal
c. backlight

A

b. liquid crystal

147
Q

What does the imaging monitor must have?

A

fast response and refresh time

148
Q

Which of the characteristic of imaging monitor change brightness?
a. fast response
b. fast refresh time

A

A

149
Q

Which of the characteristic of imaging monitor reconstruct next frame of a dynamic image?
a. fast response
b. fast refresh time

A

B

150
Q

To achieve fast response and refresh time, what is required?

A

Active Matrix LCD (AMLCD)

151
Q

What is the benefit of AMLCD?

A

read entire row of pixels at one time rather than a single pixel at a time

152
Q

What does each hardware pixel possess

A

Thin Film Transistor (TFT)

153
Q

What is the refresh rate of AMLCD?
a. 150 Hz (cycles per s)
b. 200 Hz (cycles per s)
c. 240 Hz (cycles per s)
d. 500 Hz (cycles per s)

A

C

154
Q

What are the 3 problems of AMLCD?

A

input lag, dead pixels, dark spots

155
Q

What caused input lag?
a. too much processing
b. electrical charge cant be applied across pixel
c. stucked pixels that receive constant electrical charge

A

A

156
Q

What caused dead pixels?
a. too much processing
b. electrical charge cant be applied across pixel
c. stucked pixels that receive constant electrical charge

A

B

157
Q

What caused dark spots ?
a. too much processing
b. electrical charge cant be applied across pixel
c. stucked pixels that receive constant electrical charge

A

C

158
Q

which of the following problems of AMLCD will result in appearance of permanent white dots?
a. input lag
b. dead pixels
c. dark spots

A

B

159
Q

If electrical charge cannot be applied across pixel, what is the result?

A

dead pixels - white spots

160
Q

If electrical charge constantly applied across pixels, what is the result

A

dark spots

161
Q

too much rescaling, noise reduction, and edge enhancement result in :
a. input lag
b. dead pixels
c. dark spots

A

A

162
Q

Which of the following will require the monitor to be replaced?
a. less than 15 defective pixels
b. more than 3 defective pixels in any 1cm circumference
c. more than 2 defective pixels in any 1cm circumference
d. more than 10 defective pixels

A

B

163
Q

if there are more than 15 defective pixels, will the monitor need to be replaced?

A

YES

164
Q

If there are less than 3 defective pixels next to each other, will the monitor need to be replaced?

A

NO - Replace if more than 3

165
Q

What does LCD monitor replace?

A

cathode-ray tube monitor & viewbox

166
Q

4 pros of LCD monitor that improve image quality

A
  1. no distortion or change in sharpness
  2. no glare & minimal reflection of ambient light
  3. no flicker
  4. uniform & consistent brightness
167
Q

4 cons of LCD monitor

A
  1. pixelation
  2. substantial limited contrast to 600:1
  3. sensitive to change in temperature
  4. viewing angle dependence
168
Q

what does the radiologist frequently do if contrast is limited

A

windowing

169
Q

How long does it take to warm up the monitor to reach full luminance

A

15minutes

170
Q

Increased angle of observer = ____ brightness of monitor

A

decreased

171
Q

Which of the following is the monitor sensitive to:
a. radiologist
b. temperature
c. kVp
d. brightness

A

B

172
Q

Which components determine the sharpness of image?

A

pixel and dexel size

173
Q

what does pixel size used for

A

process image

174
Q

what does dexel size used for

A

record latent image

175
Q

what determine monitor’s inherent resolution capability
a. hardware pixel
b. hardware dexel

A

a

176
Q

decreased in hardware pixel size = _____ sharpness

A

increased

177
Q

increased sharpness = _____ inherent spatial resolution

A

increased

178
Q

Which pixel size will give high resolution image?
a. 1-2mm
b. 0.1-0.2mm
c. 0.5 - 1mm
d. 0.01 - 0.002 mm

A

B

179
Q

a pixel size of 0.1-0.2mm = _____ spatial resolution

A

increased

180
Q

dot pitch aka ____

A

pixel pitch

181
Q

what is pixel pitch

A

distance bw 2 centers of any 2 adjacent hardware pixels

182
Q

smaller pixel pitch = ____ sharpness

A

sharper

183
Q

smaller pixel pitch = _____ pixel size

A

smaller

184
Q

___ focal spot = more blur than display monitor

A

large

185
Q

distal extremities should be done on _____ focal spot

A

small

186
Q

using a large focal spot on distal extremities will ____

A

more blurry images

187
Q

soft pixel display ___ image

A

light

188
Q

soft pixels can be changed by _____

A

zooming FOV in or out

189
Q

What is luminance

A

rate of light/brightness emitted from a source (LCD monitor)

190
Q

which of the following gives a standardized area to measure and compare brightness?
a. luminance
b. illuminance
c. contrast

A

A

191
Q

which of the following describe rate of light emitted in all directions
a. lux
b. lumen
c. candela

A

C

192
Q

Which of the following is a measure of illluminance
a. lux
b. lumen
c. candela

A

A

193
Q

which of the following refers to brightness of light within one single steradian
a. lux
b. lumen
c. candela

A

B

194
Q

luminous flux = _____
a. lumens
b. candela

A

A

195
Q

luminous intensity = ____
a. lumens
b. candela

A

B

196
Q

1Cd = 1 __
a. lux
b. lumen

A

B

197
Q

What is the minimum brightness capability for display system?
a. 200 Lm
b. 250 Lm
c. 300 Lm
d. 400 Lm

A

B

198
Q

Photometer use which of the following effect
a. compton scattering
b. photoelectric effect

A

B

199
Q

How much Lm radiologists typically prefer?

A

500-600Lm

200
Q

What is illuminance

A

rate of light striking a surface measured in lux

201
Q

for accurate diagnosis, ambient light should not exceed ___
a. 25 Lm
b. 25 Lux
c. 30 Lm
d. 30 Lux

A

B

202
Q

1-quarter of normal office light = ____ lux

A

25

203
Q

What is DICOM

A

digital imaging and communication in medicine

204
Q

Who developed DICOM

A

ACR

205
Q

What is PACS

A

picture archiving and communication system

206
Q

DICOM is the groundwork for ___

A

PACs

207
Q

What is archiving

A

permanent location for digital images arranged by computers & storage space

208
Q

Which method keeps a complete copy of archive in another location that is immediately available in the event that the front-line archive goes down
a. disaster recovery
b. long-term storage

A

A

209
Q

Hospitals use ____ for long-term storage
a. application service provider
b. application service user

A

A

210
Q

What does PACs consist of (3)

A

digital acquisition
display workstation
storage devices

211
Q

An electronic version of the radiologist reading room and file room is ____
a. PACs
b. DICOM

A

A

212
Q

Which is the most interactive part of PACs?
a. display workstation
b. digital acquisition

A

A

213
Q

What are the 3 common PACs

A
  1. client/server based system
  2. distributed systems
  3. web-based systems
214
Q

What do you do for monthly quality assurance testing? (4)

A

erase all plates
acquire QC phantom image
implement QC measurement
monitor calibration for QC workstations

215
Q

What are the 3 steps for monitoring calibration for QC workstation

A
  1. check spatial resolution
  2. grayscale and brightness
  3. SMPTE pattern
216
Q

Types of CR artifacts (6)

A

white specks/traces
vertical band artifact
visible plastic support
moire or aliasing
latent imaging –> double exposure/ghosting
incorrect image processing

217
Q

Types of DR artifacts (4)

A

pixel defects
ghosting
moire or aliasing
incorrect image processing

218
Q

how to correct white speck/traces

A

clean dust or hair off plates

219
Q

how to correct vertical band artifact

A

Foreign material on light collection guide

220
Q

how to correct visible plastic support

A

imaging plate and cassette upside down in cassette holder

221
Q

how to correct moire/aliasing in CR

A

grid scan frequency mismatched

222
Q

how to correct latent image

A

erase detector
short erase time or dim/burnt out bulb

223
Q

how to correct incorrect image processing CR

A

incorrect positioning/ wrong body view selected
histogram,LUT, or rescaling error

224
Q

how to correct pixel defects

A

cannot the inherent detector is defective

225
Q

how to correct ghosting in DR

A

memory effect
electrical charge is trapped

Raad 354 - Physics (2 decks)

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