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Radiology > Physics > Flashcards

Physics Flashcards

1
Q

Appropriate target range for medical audit:

Recall rate?

A

4-7%

My note: Prometheus says 4-7 in one place, 5-7 in another, and “less than 10%” in another.

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2
Q

Appropriate target range for medical audit:

Cancers/1000 screened?

A

3-8

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3
Q

How often:

Processor QC

A

Daily

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4
Q

How often:

Darkroom Cleanliness

A

Daily

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5
Q

How often:

Viewbox Conditions?

A

Weekly

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6
Q

How often:

Phantom Evaluation?

A

Weekly

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7
Q

How often:

Repeat Analysis?

A

Quarterly

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8
Q

How often:

Compression Test?

A

Semi-Annually

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9
Q

How often:

Darkroom Fog?

A

Semi-Annually

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10
Q

How often:

Screen-Film Contrast?

A

Semi-Annually

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11
Q

Places that do mammo have to be “accredited and certified”…..and pay money…. every _________.

A

3 years

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12
Q

_______ is the evil overlord begins the MQSA.

A

The FDA

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13
Q

Gaining the privilege to read mammograms: 3 criteria you must meet

A

1) read 240 mammography exams over 6 months during last 2 years of training, under direct supervision,
2) 3 months of mammography in residency,
3) 60 documented hours of mammo education

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14
Q

Spatial Resolution (mammo):

LP/mm in Anode-Cathode Direction ?

A

13 LP/mm

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15
Q

Spatial Resolution (mammo):

LP/mm in left-right Direction ?

A

11 LP/mm

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16
Q

Spatial Resolution (mammo):

MQSA resolution for screen-film: _____

A

12 LP/mm

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17
Q

Spatial Resolution (mammo):

MQSA resolution for digital: _____

A

Manufacturer specs (~ 7 LP/mm)

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18
Q

What is the MQSA breast dose phantom?

A

MQSA has breast phantom which is supposed to be an “average breast.”

  • 4.2 cm of compressed breast
  • 50% adipose, 50% glandular.
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19
Q

Dose for MQSA phantom

A

Phantom limit (per image)=

3 mGy (300 millirads) WITH GRID

1 mGy WITHOUT GRID.

Note: Dose limit ONLY for phantom!!! There is no regulation for dose to real human breast.

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20
Q

How Often:

Localization/Accuracy (for Stereotactic Biopsy)?

A

Daily before patient exams

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21
Q

Mammography facilities are required to provide patients with a “lay report”

  • what is it?
  • when does it need to be provided?
A
  • written results of the mammogram in language that is easy to understand.
  • within 30 DAYS of the study (MUST).
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22
Q

Consumer complaint mechanism is required to be established in mammography facilities to provide patients with a process for addressing their concerns.

A

.

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23
Q

Patients can have their ORIGINAL mammograms (not just copies) when they are needed.

A

.

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24
Q

If a facilities mammograms are determined to be substandard and a risk to public health, what happens?

A

Those FACILITIES will notify patients and their doctors and suggest an appropriate plan of action.

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25
Q

Who is ultimately responsible for the Quality Control program?

A

The “INTERPRETING PHYSICIAN”

Not the techs.

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26
Q

To make it (the phantom?) pass image quality, must show: _____(4 distinct things)

A
  • 4 fibers
  • 3 microcalcification clusters,
  • 3 masses
  • only “acceptable artifacts”
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27
Q

Patient dose limit in mammography

A

THERE IS NONE!

Only a dose limit for phantom (3 mGy/view). But a denser real breast could require more than 3 mGy/view.

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28
Q

Typical patient and phantom doses (not limits).

A

~2 mGy/view

~4 mGy for a two-view screening exam

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29
Q

Typical (average) compressed breast is
_______ cm,
_______ % glandularity.

A

6cm,

15-20%

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30
Q

Digital systems generally use higher beam quality, which results in ______ doses.

A

Lower

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31
Q

Digital mammography does NOT use fixed dose (screen-film). Can use as much or as little radiation as deem appropriate.

A

.

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32
Q

Nukes QC: how often to check…

Constancy

(And “Dose should be within ___% of computed activity.”)

A

Daily

5% of computed activity
Checked with reference sources

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33
Q

Nukes QC: how often to check…

Linearity

A

Quarterly

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34
Q

Nukes QC: how often to check…

Accuracy

A

At installation of device AND

Annually

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35
Q

Nukes QC: how often to check…

Geometry

A

At installation of device AND

Any time you move device

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36
Q

Does it affect Spatial resolution or Contrast resolution?:

Focal spot

A

Spatial

Smaller spot= better

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37
Q

Does it affect Spatial resolution or Contrast resolution?:

Detector Width

A

Spatial

Smaller detector = better

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38
Q

Does it affect Spatial resolution or Contrast resolution?:

Nyquist Limitations “Sampling”

A

Spatial

Oversampling = better

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39
Q

Does it affect Spatial resolution or Contrast resolution?:

Reconstruction Filter

A

Spatial

Ex: bone “sharp” algorithm gives a higher spatial resolution.

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40
Q

Does it affect Spatial resolution or Contrast resolution?:

Number of x-rays (mAs, kV, pitch)

A

Contrast

More dose—less mottle—will improve contrast resolution

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41
Q

Does it affect Spatial resolution or Contrast resolution?:

Slice thickness

A

Contrast

Thicker = more x-ray quanta = less noise

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42
Q

Does it affect Spatial resolution or Contrast resolution?:

Reconstruction Method

A

Contrast

Iterative > Filtered Back

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43
Q

Does it affect Spatial resolution or Contrast resolution?:

Reconstruction Filter

A

Contrast

Soft tissue > bone

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44
Q

Choose Increase or Decrease for all:

Holding matrix size constant and DECREASING FOV will
_______ pixel size. This will
_______ spatial resolution, and
_______ contrast resolution.

A

DECREASE pixel size
INCREASE spatial resolution
DECREASE contrast resolution
(Less photons per box)

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45
Q

Choose Increase or Decrease for all:

Holding matrix size constant and INCREASING FOV will
_______ pixel size. This will
_______ spatial resolution, and
_______ contrast resolution.

A

INCREASE pixel size
DECREASE spatial resolution
INCREASE contrast resolution
(More photons per box)

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46
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Shorter pulses

A

Axial

Smaller spatial pulse length

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47
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Greater Damping “Low Q”

A

Axial

Shorter pulses

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48
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Higher frequency

A

Axial

Shorter wavelength

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49
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Narrowing the beam in the proximal field (adding an acoustic lens). Minimal necessary gain (gain widens the beam).
I.e. “Put the thing you want to look at in the focal zone.”

A

Lateral

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50
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Phased array with multiple focal zones

A

Lateral

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51
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Increasing the “line density” or lines per cm

A

Lateral

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52
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Use fixed focal length across the entire surface of the array (downside is partial volume effects)

A

Elevation

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53
Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Minimize slice thickness— done by phase excitation of the outer to inner arrays

A

Elevation

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54
Q

Axial Resolution is dependent on ________

A

Spatial Pulse Length

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55
Q

Lateral Resolution is dependent on ________

A

Transducer Element WIDTH

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56
Q

Elevation Resolution is dependent on ________

A

Transducer element HEIGHT

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57
Q

Artifacts:

Reverberation—what causes it?

A

Two parallel highly reflective surfaces

My note: looks like description might have been cut off. May want to double check not missing something

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58
Q

Artifacts:

Comet tail—what causes it?

A

Two parallel highly reflective surfaces —closer together (<1/2 SPL)

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59
Q

Artifacts:

Ring Down Artifact —what causes it?

A

Fluid trapped between tetrahedron of air bubbles

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60
Q

Artifacts:

Mirror Image—what causes it?

A

Trapped behind a strong reflector

My note: not sure this is complete…

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61
Q

Artifacts:

Reverberation—what does it look like?

A

Multiple equidistantly spaced linear reflections.

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62
Q

Artifacts:

Comet tail—what does it look like?

A

Triangle (comet) shaped…

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63
Q

Artifacts:

Ring Down Artifact—what does it look like?

A

Parallel band extending posterior to a collection of gas

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64
Q

Artifacts:

Mirror image—what does it look like?

A

This is almost always shown with the liver on lung.

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65
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Thicker Slices

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

INCREASED signal to noise,
DECREASED spatial resolution,
NO EFFECT on duration of exam

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66
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Larger Field of View

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

INCREASED signal to noise,
DECREASED spatial resolution,
NO EFFECT on duration of exam

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67
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Larger Matrix

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

DECREASED signal to noise,
INCREASED spatial resolution,
INCREASED duration of exam

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68
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Greater Field Strength

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

INCREASED signal to noise
NO EFFECT on spatial resolution
NO EFFECT on duration of exam

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69
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Greater Receiver Bandwidth

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

DECREASED signal to noise
NO EFFECT on spatial Resolution
DECREASED duration of exam

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70
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Greater Transmit Bandwidth

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

INCREASED signal to noise,
DECREASED spatial resolution,
NO EFFECT on duration of exam

71
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

More Excitations per Slice

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

INCREASED signal to noise,
NO EFFECT spatial resolution,
INCREASED duration of exam

72
Q

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification:

Utilizing Partial K Space Sampling

  • Signal to Noise
  • Spatial Resolution
  • Duration of Exam
A

DECREASED signal to noise
NO EFFECT on spatial resolution
DECREASED duration of exam

73
Q

Artifact: Aliasing

Direction?

A

Phase encoding

74
Q

Artifact: Chemical Shift

Direction?

A

Frequency encoding

75
Q

Artifact: Gibbs/Truncation

Direction?

A

Both phase AND frequency encoding

76
Q

Artifact: Motion Artifact

Direction?

A

Phase encoding

77
Q

Artifact: Zipper

Direction?

A

Phase encoding

78
Q

Artifact: Aliasing

Does it make it better or worse if you

Increase the field of view?

A

Better

79
Q

Artifact: Aliasing

Does it make it better or worse if you

Change the phase encoding direction

A

Better

80
Q

Artifact: Aliasing

Does it make it better or worse if you

Smaller FOVs

A

Worse!

81
Q

Artifact: Chemical Shift

Does it make it better or worse if you

Bigger Pixels

A

Better

82
Q

Artifact: Chemical Shift

Does it make it better or worse if you

Fat suppression

A

Better

83
Q

Artifact: Chemical Shift

Does it make it better or worse if you

Increase Receiver Bandwidth

A

Better

84
Q

Artifact: Chemical Shift

Does it make it better or worse if you

Stronger magnetic field

A

Worse!

85
Q

Artifact: Chemical Shift

Does it make it better or worse if you

Lower receiver bandwidth

A

Worse!

86
Q

Artifact: Gibbs/Truncation

Does it make it better or worse if you

Bigger matrix

A

Better

87
Q

Artifact: Gibbs/Truncation

Does it make it better or worse if you

Decrease bandwidth

A

Better

88
Q

Artifact: Gibbs/Truncation

Does it make it better or worse if you

Decrease pixel size (increase PE Steps, decrease FOV)

A

Better

89
Q

Artifact: Partial Volume

Does it make it better or worse if you

Decrease pixel size (increase PE Steps, decrease FOV)

A

Better

90
Q

Artifact: Partial Volume

Does it make it better or worse if you

Thicker slices

A

Worse!

91
Q

Artifact: Motion Artifact

Does it make it better or worse if you

Saturation pulses

A

Better

92
Q

Artifact: Motion Artifact

Does it make it better or worse if you

Respiratory gating

A

Better

93
Q

Artifact: Motion Artifact

Does it make it better or worse if you

Faster sequences (BLADE, PROPELLER)

A

Better

94
Q

Artifact: Cross Talk

Does it make it better or worse if you

Increase slice gap

A

Better

95
Q

Artifact: Cross Talk

Does it make it better or worse if you

Interleave slices

A

Better

96
Q

Artifact: Field Inhomogeneity

Does it make it better or worse if you

Shimming

A

Better

97
Q

Artifact: Field Inhomogeneity

Does it make it better or worse if you

GRE Sequences

A

Worse!

98
Q

Artifact: Susceptibility

Does it make it better or worse if you

GRE Sequences

A

Worse!

99
Q

Artifact: Eddy Current

Does it make it better or worse if you

Optimize sequence of gradient pulses

A

Better

100
Q

Artifact: Eddy Current

Does it make it better or worse if you

DWI-large gradient changes

A

Worse!

101
Q

Artifact: Dielectric Effects

Does it make it better or worse if you

Parallel transmit

A

Better

102
Q

Artifact: Dielectric Effects

Does it make it better or worse if you

Use 1.5T

A

Better

103
Q

Artifact: Dielectric Effects

Does it make it better or worse if you

3T

A

Worse!

104
Q

Artifact: Magic Angle

Does it make it better or worse if you

T2

A

Better

105
Q

Artifact: Magic Angle

Does it make it better or worse if you

T1, PD

A

Worse!

106
Q

Artifact: Magic Angle

Cause?

A

Occurs at 55 degrees

107
Q

Artifact: Dielectric effects

Cause?

A

Standing waves created as radiowave approaches length of body part

(My note: unclear if this is a cause or just trivia…they share a box in chart.)

108
Q

Artifact: Eddy Current

Cause?

A

Caused by geometric distortion or non-uniformity

109
Q

Artifact: Susceptibility

Cause?

A

Augmentation of magnetic field.

Trivia: very bad in EPI

110
Q

Artifact: Field Inhomogeneity

Cause?

A

Geometric distortion

111
Q

Artifact: Zipper

Cause?

A

Poor shielding

112
Q

Artifact: Cross Talk

Cause?

A

Overlap of slices

113
Q

Artifact: Gibbs/Truncation

Cause?

A

Limited sample of FID

114
Q

Artifact: Gibbs/Truncation

Classic location?

A

Spinal cord

115
Q

Artifact: Chemical Shift

Cause?

A

Differences in resonance frequencies

116
Q

Artifact: Aliasing

Cause?

A

A small FOV

117
Q

Major spill, how much is it?:

Tc-99m

A

100 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

118
Q

Major spill, how much is it?:

Tl-201

A

100 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

119
Q

Major spill, how much is it?:

In-111

A

10 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

120
Q

Major spill, how much is it?:

Ga-67

A

10 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

121
Q

Major spill, how much is it?:

I-131

A

1 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

122
Q

Radionuclide Purity (Tc):

  • what is it?
  • how is it tested?
A

What: “How much Mo in the Tc?”

Tested: in a dose calibrator with lead shields

123
Q

Chemical Purity (Tc):

  • what is it?
  • how is it tested?
A

What: how much Al in the Tc?

Tested: with pH paper

124
Q

Radiochemical Purity (Tc):

  • what is it?
  • how is it tested?
A

What: How much free Tc?

Tested: thin layer chromatography

125
Q

Acute Radiation Syndrome:

Bone marrow—dose needed?

A

> 2 Gy

[ Bone Marrow:
>2 Gy,
1-6 wk latent period,
Can live.]

126
Q

Acute Radiation Syndrome:

Bone marrow—latent period?

A

1-6 weeks

[Bone Marrow:
>2 Gy,
1-6 wk latent period,
Can live.]

127
Q

Acute Radiation Syndrome:

Bone marrow—outcome?

A

Worse with higher dose. It’s possible to survive.

[Bone Marrow:
>2 Gy,
1-6 wk latent period,
Can live.]

128
Q

Acute Radiation Syndrome:

GI—dose needed?

A

> 8 Gy

[GI:
> 8 Gy,
5-7 day latent period,
death within 2 weeks.]

129
Q

Acute Radiation Syndrome:

GI—latent period?

A

5-7 days

[GI:
> 8 Gy,
5-7 day latent period,
death within 2 weeks.]

130
Q

Acute Radiation Syndrome:

GI—outcome?

A

Death with 2 weeks

[GI:
> 8 Gy,
5-7 day latent period,
death within 2 weeks.]

131
Q

Acute Radiation Syndrome:

CNS—dose needed?

A

> 20-50 Gy

[CNS:
> 20-50 Gy,
4-6 hour latent period,
death within 3 days.]

132
Q

Acute Radiation Syndrome:

CNS—latent period?

A

4-6 hours

[CNS:
> 20-50 Gy,
4-6 hour latent period,
death within 3 days.]

133
Q

Acute Radiation Syndrome:

CNS—outcome?

A

Death within 3 days

[CNS:
> 20-50 Gy,
4-6 hour latent period,
death within 3 days.]

134
Q

Acute Radiation sickness:

WB Dose: < 1 Gy

  • Effect on GI
  • Effect on skin
  • Action needed
A

GI: no vomiting

Skin: no redness

Action: surveillance for 5 weeks

135
Q

Acute Radiation sickness:

WB Dose: 1-2 Gy

  • Effect on GI
  • Effect on skin
  • Action needed
A

GI: vomiting 2-3 hours after exposure

Skin: redness 12-24 hours after

Action: surveillance for 3 weeks, consider general hospital

136
Q

Acute Radiation sickness:

WB Dose: 2-4 Gy

  • Effect on GI
  • Effect on skin
  • Action needed
A

GI: vomiting 1-2 hours after

Skin: redness 8-15 hours after

Action: hospitalize - burn center

137
Q

Acute Radiation sickness:

WB Dose: > 4 Gy

  • Effect on GI
  • Effect on skin
  • Action needed
A

GI: vomiting < 1 hour after

Skin: redness 1-6 hours after

Action: hospitalize - Specialized radiation center

138
Q

Transient equilibrium:

What is it?

Classic example?

How long until achieved? (In half lives)

A

Equilibrium that occurs when half life of the daughter is shorter than the parent (but not by a lot).

Classic example: Moly-99 generator making Tc-99.

A transient equilibrium happens after 4 half lives (usually).

139
Q

Routine premedication:

2 methods

  • drugs
  • doses
  • routes
  • frequencies
A 
Method 1:
  -prednisone, 50 mg, PO
        -13 hours, 7 hours, 1 hour 
                    (before contrast)
  -diphen (50 mg IV) 1 hour before (can PO)
Method 2:
  -methylprednisolone, 32 mg, PO
        -12 hours, 2 hours
                    (before contrast)
  -diphen (50 mg IV) 1 hour before (can PO)

[NOTE: diphen present and EXACTLY same for ALL premeds.]

140
Q

Emergent Premedication:

3 methods:

  • drugs
  • doses
  • route
  • frequency
A 
Method 1:
  -methylprednisolone, 40 mg, IV
             OR 
    hydrocortisone sod. succ., 200 mg, IV 
        -q4 until contrast 
  -diphen (50 mg IV) 1 hour before
Method 2:
*If NSAID allergy or history asthma
  -dexamethasone sodium, 7.5 mg, IV
              OR
    Betamethasone, 6 mg, IV
        -Q4 until contrast 
  -diphen (50 mg IV) 1 hour before

Method 3:

  • If can’t give steroids—infection, risk of bowel perforation
  • just diphen (50 mg IV) 1 hour before

[NOTE: diphen is present and EXACTLY same for all!]

141
Q

Exposure Dose Limits:

Occupational workers:

Minimal age?

A

18 years

142
Q

Exposure Dose Limits:

Occupational workers:

Lens?

A

150 mSv/yr

“(Some new papers say 20 mSv)”

143
Q

Exposure Dose Limits:

Occupational workers:

Radiation worker?

A

50 mSv /yr

144
Q

Exposure Dose Limits:

Occupational workers:

Extremity?

A

500 mSv/yr

145
Q

Exposure Dose Limits:

Public Exposure:

Infrequent?

A

5 mSv/yr

146
Q

Exposure Dose Limits:

Public Exposure:

Continuous ?

A

1 mSv/yr

147
Q

Exposure Dose Limits:

Public Exposure:

Embryo/fetus via MOTHER?

A

5 mSv/yr (1 mSv to fetus directly)

148
Q

Exposure Dose Limits:

Public Exposure:

Embryo Fetus (post declared pregnancy)?

A

0.5 mSv/MONTH

149
Q

Exposure Dose Limits:

Public Exposure:

Controlled areas?

A

50 mSv/yr

150
Q

Exposure Dose Limits:

Public Exposure:

Uncontrolled areas?

A

5 mSv/yr

151
Q

Exposure Dose Limits:

Public Exposure:

Genetically Significant Dose?

A

0.25 mSv

152
Q

Exposure Dose Limits:

Public Exposure:

Effective dose from background radiation in US?

A

3 mSv/yr

153
Q

Package labels: what does it mean??

WHITE 1

  • special handling?
  • surface dose rate?
  • 1 meter dose rate?
A

no special handling

Surface: < 0.5 mrem/hr

1 meter: 0 mrem/hr

154
Q

Package labels: what does it mean??

YELLOW 2

  • special handling?
  • surface dose rate?
  • 1 meter dose rate?
A

-special handling, yes

Surface: < 50 mrem/hr

1 meter: < 1 mrem/hr

155
Q

Package labels: what does it mean??

YELLOW 3
*bc the assholes couldn’t choose another color

  • special handling?
  • surface dose rate?
  • 1 meter dose rate?
A

Special handling, yes

Surface: < 200 mrem/hr

1 meter: < 10 mrem/hr

156
Q

MRI

2D Table Time formula

A

Time=TR x Phase Matrix x NEX

TR: time between each RF pulse (usu in milliseconds)

Phase Matrix: data the system collects from each phase encoding step

NEX: number of times each set of phase encoding steps is repeated (Number of EXcitations)

157
Q

MRI

3D Table Time Formula

(Note: unless they specify 3D in question, you should assume it’s 2D).

A

Time=TR x Phase Matrix x NEX x # Slices!!!

[slices # is what’s different from 2D!]

TR: time between each RF pulse (usu in milliseconds)

Phase Matrix: data the system collects from each phase encoding step

NEX: number of times each set of phase encoding steps is repeated (Number of EXcitations)

158
Q

MRI

Better Spatial Resolution if:
Small or Large VOXEL?

A

SMALL voxel

159
Q

MRI

Better Spatial Resolution if:
Small or Large FIELD OF VIEW?

A

SMALL Field of view

160
Q

MRI

Better Spatial Resolution if:
Smaller or Larger MATRIX?

A

LARGER matrix

161
Q

MRI

Better Spatial Resolution if:
Thinner or Thicker SLICES?

A

THINNER slices

162
Q

MRI

Better Spatial Resolution if:

“Steep (Large) Slice Selection Gradient, and Thin Transmit Bandwidth”

A

.

163
Q

MRI

Better SNR if:
Weaker or Stronger magnet?

A

STRONGER magnet

164
Q

MRI

Better SNR if:
Short or Long TR?

A

LONG TR

165
Q

MRI

Better SNR if:
Small or Big FOV?

A

BIG FOV

166
Q

MRI

Better SNR if:
Small or Large SLICES?

A

LARGE slices

167
Q

MRI

Better SNR if:
Less or More NEX?

A

MORE NEX

168
Q

MRI

Better SNR if:
Short or Long TE

A

SHORT TE

169
Q

MRI

Better SNR if:
Small or Large Matrix?

A

SMALL Matrix

170
Q

MRI

Better SNR if:
Small or Large Receiver Bandwidth?

A

SMALL Receiver Bandwidth

171
Q

MRI

Better SNR if:
_______ COIL SIZE

A

Appropriate

172
Q

MRI

Better SNR if:

“Shallow (small) slice selection gradient, and Thick transmit bandwidth”

A

.

173
Q

MRI, Potential Fuckery:
Terms that sound very similar!

Fat Receiver Bandwidth = _____ SNR
Fat TRANSMIT Bandwidth = _____ SNR (Small or Large slice?)

A

Fat Receiver Bandwidth =DECREASE SNR

Fat TRANSMIT Bandwidth = Large slice= Increased SNR

174
Q

MRI, Potential Fuckery:
Terms that sound very similar!

Narrow Receiver Bandwidth = _____ SNR
Narrow TRANSMIT Bandwidth = _____ SNR (Small or Large slice?)

A

Narrow Receiver Bandwidth = INCREASED SNR

Narrow TRANSMIT Bandwidth = Small/Thin slice = DECREASED SNR

Radiology (8 decks)

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