Radiography 2 Flashcards Preview

FINALS - SPRING 2016 > Radiography 2 > Flashcards

Flashcards in Radiography 2 Deck (99):
1

To make a visible change in density, one must increase or decrease mAs by ____%.

30%

2

Is mAs directly or indecently proportional to patient dose?

Directly

3

KVp is the main controlling factor of _______.

Contrast

4

KVp also affects density mainly because it also controls ______.

Scatter

5

Inverse Square Law:
If you double the distance, you cover ____ the area with ____ the intensity

4x
1/4

6

15% Rule involves _____.

KVp

7

30% Rule involves ____.

mAs

8

15% Rule
Below 90 kVp:
+10 kV =
-10kV =

Cut mAs in 1/2
Double mAs

9

15% Rule
Above 90 kVp:
+15 kV =
-15 kV =

Cut mAs in 1/2
Double mAs

10

Inverse Square Law:
If you cut distance in 1/2, you cover ____ the area with _____ the intensity.

1/4
4x

11

Increased OID = _______ density
(Due to Air Gap & scatter bypassing IR)

Decreased

12

Increased speed screen = ________ mAs, pt dose, and detail

Decreased

13

Decreased speed screen = ______ mAs, pt dose, and detail

Increased

14

Increased collimation (smaller field size) = ______ density

Decreased

15

Decreased collimation (larger field size) = ______ density

Increased

16

ARRT calls density __________ or "RE"

Receptor Exposure

17

As part density increases, IR density _________.

Decreases

18

As part density decreases, IR density (RE) ________.

Increases

19

Degrees of differences in density

Contrast

20

High KV:
______ scale
______ contrast
______ colors
______ latitude
______ pt dose
______ scatter
______ penetration

Long
Low
Many
Wide
Decreased
Increased
More

21

Low KV:
______ scale
______ contrast
______ colors
______ latitude
______ pt dose
______ scatter
______ penetration

Short
High
Few
Narrow
Increased
Decreased
Less

22

TBMFG

Teeth
Bone
Muscle
Fat
Gas

23

Increased grid ratio = _______ contrast (less scatter)

Increased

24

Decreased grid ratio = _______ contrast (more scatter)

Decreased

25

Increased collimation = ________ contrast

Increased

26

Decreased collimation = ________ contrast

Decreased

27

Additive Pathology requires a/an _______ in technique

Increase

28

Destructive Pathology requires a/an _______ in technique

Decrease

29

3 geometric factors that control recorded detail:

Focal Spot (small)
OID (short)
SID (long)

30

Additive Pathology ex: (2)

Pneumonia
CHF

31

Destructive Pathology ex: (3)

Emphysema
COPD
Osteoporosis

32

As focal spot size increases, unsharpness (penumbra) _________ and recorded detail (umbra) _______.

Increases
Decreases

33

As focal spot size decreases, unsharpness (penumbra) _________ and recorded detail (umbra) _______.

Decreases
Increases

34

Penumbra

Unsharpness

35

Umbra

Recorded Detail

36

As SID increases, unsharpness (penumbra) ______ and recorded detail (umbra) _______.

Decreases
Increases

37

As SID decreases, unsharpness ______ and recorded detail ________.

Increases
Decreases

38

As OID decreases, unsharpness ______ and recorded detail ________.

Decreases
Increases

39

As OID increases, unsharpness ______ and recorded detail ________.

Increases
Decreases

40

Greatest enemy of detail is _______.

Motion

41

3 ways to overcome motion

Short exposure time
Clear concise instructions
Immobilization

42

Size distortion

Magnification

43

To overcome dose distortion (magnification)

Use short OID and long SID

44

Shape distortion

True distortion

45

Shape distortion is caused by

Mal-alignment of tube, part, and/or IR

46

2 types of shape (true) distortion

Elongation
Foreshortening

47

Increased collimation =
______ scatter, density and patient dose
______ contrast

Decreased
Increased

48

Decreased collimation =
______ scatter, density and patient dose
______ contrast

Increased
Decreased

49

Piece of lead that is not a type of variable collimator

Aperture Diaphragm

50

Form a round pattern on the IR

Cones and cylinders

51

A VARIABLE collimator

Box-type collimator

52

Automatic Collimator aka

Positive Beam Limitation (PBL)

53

Automatic Collimator / PBL can only be used in the _______

Bucky

54

Organic grid interspacers

Cardboard
Balsa wood

55

Inorganic grid interspacer

Aluminum

56

Focused grid (does / does not) have a required focusing distance

Does

57

Peripheral Grid Cut-off

Acceptable density in the middle, too light on the edges

58

If you use SID or if you use it upside down, you will get:

Peripheral grid cut off

59

Grid that does not have a required focusing distance

Parallel / non-focused

60

You cannot angle with a ________ grid

Crossed / Cross Hatch

61

With regular grids you never angle _____________ - only caudal or cephalic

Across grid lines

62

Cross hatch is most _________.

Restrictive

63

______ and ______ are stationary, whereas Bucky grids are moving

Portable
Tabletop

64

The higher the grid ratio, the more _____ it is to use

Restrictive

65

If a part measures ______ or more, use a grid

10 cm

66

Grid Ratio

Height of BP strips / distance between pb strips

67

Amount of blackness on image after processing

Density

68

Types of grid cut off errors: (3)

Off level
Off center
Off focus

69

Air-gap technique uses _______ OID to allow scatter to by-pass the IR and act as a grid

Increased

70

Most common ex of air gap technique is _____________.

Later C-Spine

71

6" air gap = _____ grid

6:1

72

________ Radiography uses an Imaging Plate (IP).

Computed

73

_______ has a phosphor layer made of Barium Fluorohalide Crystals doped with Eurpoium, called a Photostimulable Phosphor (PSP) where the latent image is formed

CR

74

Exposed IP then put in reader where a __________ scans over PSP to release stored energy as ________.

Neon laser
Visible light

75

A ___________ tube (PMT) collects light and converts it into an electronic signal and sends it to an __________ Converter (ADC) for viewing.

Photomultiplier
Analog-to-Digital

76

An _____________ passes over PSP to remove any remaining energy

Intense white light

77

__________ Radiography uses Flat Panel Detectors that have a Thin-Film Transitor (TFT)

Direct Digital (DR)

78

Flat Panel Detectors have a TFT layer divided into ____________.

Detector Elements (DELs)

79

_______ DR involves a 2 step process of converting X-ray first into visible light then into electric charges during image acquisition

Indirect

80

_______ DR is typically made of Cesium Iodine or Amorphous Silicon (a-Si)

Indirect

81

______ DR uses Amorphous Selenium (a-Se) to convert exit radiation directly into electrical charges

Direct

82

CR and DR have a much _____ dynamic range than analog (film-screen) imaging

Wider

83

Increasing the Signal To Noise Ratio (SNR) _____ visibility of an atomic details

Increases

84

Film has emulsion on both sides

Duplitized

85

Duplitized films are used in ______ cassettes.

Regular

86

_______ cassettes use single emulsion films.

Extremity

87

Matching screen color to film sensitivity

Spectral matching

88

Intensifying screen converts X-rays into _____.

Light

89

Calcium Tungstate gives off _____ light

Blue

90

Rare Earth gives off _____ light

Green

91

Emission of light from screen when stimulated by radiation

Luminescence

92

Giving off light only while being exposed

Fluorescence

93

Phosphorescence

Screen lag / glowing too long

94

Factors affecting screen speed: (6)

Phosphor size
Thickness of active layer
Type of phosphor
Reflective layer
Light absorbing layer
KVp

95

Graininess of image due to fast screen system

Quantum Mottle or "Noise"

96

To control Quantum Mottle or "Noise" ...

Increase mAs and decrease kVp

97

_____ imaging plates use Barium Fluorhalide doped with Europium as the Photostimulable Phosphor

CR

98

Indirect Conversion System uses Cesium Iodine which creates light that interacts with amorphous silicon (a-Si) to create electric charge

DR

99

______ conversion system uses amorphous selenium (a-Se) to produce electric charge

Direct