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SPRING 2024: Principles II > UNIT 1: Quality Factors Review > Flashcards

UNIT 1: Quality Factors Review Flashcards

1
Q

What are the 4 quality factors of X-Ray?

A

-Photographic: IR Exposure, Contrast
-Geometric: Spatial Resolution(detail), Distortion(Magnification & Foreshortening/Elongation)

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2
Q

IR exposure is a measurement of

A

-Total amount of signal received by the Image Receptor
-Measurement of beam INTENSITY
Sensitivity Number (S#)
Exposure Index (El)
Log Median Exposure (LgM)

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3
Q

Describe the relationship that the following factors have on IR exposure: mAs, kVp, Grids, Distance

A

-mAs: direct and proportional relationship
-kVp: direct relationship (uses 15% rule)
-Grid: indirect relationship (uses GCF), manipulate mAs to maintain IR exposure
-Distance: indirect relationship (uses Inverse Square Law)

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4
Q

What are 3 additional influencing factors that affect IR exposure?

A
  • Patient Factors
    -OID
    -Screen Speed
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5
Q

If S number is too high, is the image over or underexposed?

A

Underexposed

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6
Q

If S number is too low, is the image over or underexposed?

A

Overexposed

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7
Q

Image vs Subject Contrast

A

-Image Contrast: difference in IR exposure between two adjacent areas on an image
-Subject Contrast: difference in x-ray intensities that are transmitted through the subject(patient) and recorded on the IR

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8
Q

Long Scale vs Short Scale Contrast

A

-Long Scale: many shades of gray (more information)
-Short Scale: few shades of gray yet more “appealing” to the eye

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9
Q

Describe the relationship that the following factors have on Subject Contrast: kVp, Grid, OID, Collimation

A

-kVp: indirect relationship
-Grid: direct relationship
-OID: direct relationship
-Collimation: direct relationship

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10
Q

What are 3 additional influencing factors that affect Subject Contrast?

A

-Patient factors
-Contrast media
-Filtration(?)

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11
Q

What is the purpose of the Look Up Table?

A

-Determine a preset grayscale for display based on the selection of the Radiographer
-Applied to the data that has standard contrast for that exam to give the desired image contrast for display

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12
Q

Define Spatial Resolution

A

Degree of sharpness, or accuracy of the structural lines recorded on the image

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13
Q

Describe the relationship that the following factors have on Spatial Resolution: FSS, SID, OID, Pixel Size

A

-FSS: indirect relationship
-SID: direct relationship
-OID: indirect relationship
-Pixel Size: indirect relationship

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14
Q

What are 3 additional influencing factors that affect Spatial Resolution?

A

-Quantum mottle
-Motion
-Scatter(only impacts visibility, NOT recorded detail)

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15
Q

What tool is used to measure spatial resolution?

A

Line pair test

*more lines= better resolution

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16
Q

Define Distortion and its types

A

The misrepresentation of the size or shape of a structure being examined
-Magnification
-Foreshortening
-Elongation

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17
Q

What are the two types of shape distortion and what causes them?

A

-Foreshortening: Part and IR alignment
-Elongation: Tube and IR alignment

18
Q

How does size distortion happen?

A

-Big OID
-Small SID

19
Q

Formulas

A
20
Q

Factors affecting image quality chart

A
21
Q

Frequency

A

cycles per unit of time

22
Q

Wavelength

A

Distance between two waves

23
Q

Amplitude

A

Height of the wave

24
Q

mAs

A

-Total current sent to the Cathode during exposure
-Controls the number of electrons in the thermionic cloud
-Controls Beam Intensity/quantity

25
Q

kVp

A

-Controls the Voltage sent to the anode
-Controls the attraction between the electrons and the anode
-Affects both quality (but can also affect quantity)

26
Q

Low kVp = ______ frequency

A

Low

27
Q

High kVp = _______ frequency

A

High

28
Q

A 15% increase in kVp means a _________ exposure to the IR

A

Double

29
Q

A 15% decrease in kVp means _________ exposure to the IR

A

Half

30
Q

Beam quantity is known as

A

-mAs
-beam intensity
-amplitude

31
Q

Beam quality is known as

A

-kVp
-beam penetrability
-energy
-frequency

32
Q

T or F: wavelength and frequency are inversely proportional

A

True

33
Q

Cathode serves as a

A

source of electrons

34
Q

Anode serves as

A

a target, it is the source of the x-ray beams

35
Q

If we doubled the distance, the intensity would decrease by a factor of

A

4

36
Q

If we tripled the distance, the intensity would decrease by a factor of

A

9

37
Q

Quantum mottle

A

Inconsistent or uneven distribution of x-ray photons on the surface of the IR resulting in insufficient exposure

38
Q

T or F: exposure and brightness are directly related

A

False

39
Q

CR vs DR

A
40
Q

Is quantum mottle over or under exposure

A

Under exposure

41
Q

X-ray tube labeled

A

SPRING 2024: Principles II (13 decks)

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