Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Fluoro > Flashcards

Fluoro Flashcards

1
Q

How does Fluoro compare to general radiographs?

A
  1. Smaller Focal Spot(0.3-0.6mm)
  2. Smaller mA (0-5)
  3. Longer Exposure time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does a spot image compare to a last image hold?

A
  1. Larger Focal Spot
  2. More Dose
  3. Better Spatial Resolution (3 lp mm)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When is the source above the table and what are the side effects?

A
  • Above Table in GU radiology

- Increase dose to the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does the image intensifier work?

A
  1. Hits the Input phosphor (CSI) which converts X rays to Light
  2. Photocathode Converts the Light to Electrons
  3. Electrons move towards output phosphor with beams being focus by focusing electrodes
  4. Output Phosphor converts electrons to light (minification)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the image inverted and Reversed on the output phosphor?

A

Due to point inversion (all pass through the same focusing point)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Brightness Gain?

A

-Ability of the II to convert xray signal to light and increase brightness
=Flux Gain X Minification Gain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Flux Gain?

A
  • Increase in Magnitude of the input to the output phosphor due to voltage applied which increases the energy of the electrons
  • Accelerating Electron= More Brightness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Minification gain?

A
  • Small size of output phosphor in comparison to input phosphor, means that more electrons for unit area–> More energy per unit area.
  • Reducing image size= Increased Brightness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is Conversion gain?

A

Efficiency of the II at making x rays into light at output surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to brightness and conversion gain with older II?

A

They are less efficient and require a higher dose to create the same level of brightness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When do you change image intensifier?

A

When the conversion gain falls below 50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is electronic magnification?

A

Making the input field of view smaller (increases dose) by magnifying the II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does Electronic Magnification affect spatial resolution?

A

Increased Electronic Magnification increases spatial resolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do you determine if geometric magnification will increase or decrease spatial resolution?

A

R/F Ratio: Intrinsic Receptor Resolution/Focal Spot
If < 0.5, then it decreases resolution
If >0.5, then it increases resolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does double the distance from the patient to source do to dose?

A

Decreases its by 4 times due to inverse square law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does collimation do to dose and scatter?

A

Decreases dose and scatter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the Automatic Exposure Rate control limit?

A

10 R/Min or 87 mGy/min

18
Q

What is KERMA?

A

Kinetic energy released per unit mass

=Total Energy Deposited (Heat/Ionization)/Mass

19
Q

What is Air KERMA?

A
  • Estimates the peak skin dose

- Total number of photons in the air right before you hit the skin

20
Q

What is Kerma Area Product?

A

-Dose X Cross sectional area of X ray beam

21
Q

How does electronic magnification affect KAP and Air Kerma?

A
  • Increases Air Kerma bc the dose is increase

- Keeps KAP the same, smaller CSA to balance increased dose

22
Q

What is the Air Kerma Limit?

A

10 Roetngens/min or 87 mGy/min

23
Q

What is high level control for air kerma limit?

A

20 Roetngens/Min or 176 mGy/min

24
Q

What is pincushion artifact?

A

Bent lines in the periphery due to Large FOV

25
Q

What is S Distortion?

A

Distorted field due to earths magnetic field
Worse with larger FOV
Fix with Mu metal

26
Q

What is Lag Artfact?

A

Move the II and a Ghosted image is superimposed

27
Q

What is vignetting Artifact?

A

Edges are Darker than the center

28
Q

How does the FPD work in Fluoro?

A
  1. X Rays pass through Carbon Fiber Surface (protective layer)
  2. Hit CSI which converts x rays to light
  3. Photodiode converts light to Electrons
  4. Electrons get read out with read out elements
29
Q

What is pitch?

A

Linear dimension of the detector element

30
Q

What is Fill Factor?

A 
Sensitive Area (to light)/Pitch^2
-% of the Photodiode in the Detector element
31
Q

What determines Pixel Size?

A

FOV/Matrix

32
Q

What is Binning?

A

Combine several detector elements to make one large Detector element (only with Flat Panel detectors)

  • Decreases spatial resolution
  • Less mottle (Decrease radiation with same noise)
  • Improves SNR Ratio
33
Q

What artifacts are seen with FPD?

A
  • Lag (ghosting) and Bad Pixel

- No Vignetting, Pincushion, Glare, saturation or S distortion

34
Q

What limits resolution in II and FPD Fluoro system?

A

II: TV Display
FPD: Detector element Size

35
Q

Does II or FPD have better spatial resolution?

A

II

36
Q

How does Pulsed Fluoro Reduce Dose?

A
  • Reduces dose if pulse frame rate is less than 30 pulses/Second
  • 50% decrease in Pulse frame rate= 30% decrease in dose
37
Q

How does pixel binning affect spatial resolution?

A

Decreases spatial resolution

38
Q

What KVP do you choose to maximize iodine and barium?

A

Iodine: 70 kVp
Barium: 100 kVp

39
Q

How is DSA Made?

A
  • Removes anything that is not moving

- Performed at 70 kVp

40
Q

Where is the best place for the IR doc to stand?

A

Next to the image receptor (more compton scatter where the x rays enter the patient)

Physics (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions