Radiography 2 Flashcards
(99 cards)
1
Q
To make a visible change in density, one must increase or decrease mAs by ____%.
A
30%
2
Q
Is mAs directly or indecently proportional to patient dose?
A
Directly
3
Q
KVp is the main controlling factor of _______.
A
Contrast
4
Q
KVp also affects density mainly because it also controls ______.
A
Scatter
5
Q
Inverse Square Law:
If you double the distance, you cover ____ the area with ____ the intensity
A
4x
1/4
6
Q
15% Rule involves _____.
A
KVp
7
Q
30% Rule involves ____.
A
mAs
8
Q
15% Rule
Below 90 kVp:
+10 kV =
-10kV =
A
Cut mAs in 1/2
Double mAs
9
Q
15% Rule
Above 90 kVp:
+15 kV =
-15 kV =
A
Cut mAs in 1/2
Double mAs
10
Q
Inverse Square Law:
If you cut distance in 1/2, you cover ____ the area with _____ the intensity.
A
1/4
4x
11
Q
Increased OID = _______ density
Due to Air Gap & scatter bypassing IR
A
Decreased
12
Q
Increased speed screen = ________ mAs, pt dose, and detail
A
Decreased
13
Q
Decreased speed screen = ______ mAs, pt dose, and detail
A
Increased
14
Q
Increased collimation (smaller field size) = ______ density
A
Decreased
15
Q
Decreased collimation (larger field size) = ______ density
A
Increased
16
Q
ARRT calls density __________ or “RE”
A
Receptor Exposure
17
Q
As part density increases, IR density _________.
A
Decreases
18
Q
As part density decreases, IR density (RE) ________.
A
Increases
19
Q
Degrees of differences in density
A
Contrast
20
Q
High KV: \_\_\_\_\_\_ scale \_\_\_\_\_\_ contrast \_\_\_\_\_\_ colors \_\_\_\_\_\_ latitude \_\_\_\_\_\_ pt dose \_\_\_\_\_\_ scatter \_\_\_\_\_\_ penetration
A
Long Low Many Wide Decreased Increased More
21
Q
Low KV: \_\_\_\_\_\_ scale \_\_\_\_\_\_ contrast \_\_\_\_\_\_ colors \_\_\_\_\_\_ latitude \_\_\_\_\_\_ pt dose \_\_\_\_\_\_ scatter \_\_\_\_\_\_ penetration
A
Short High Few Narrow Increased Decreased Less
22
Q
TBMFG
A
Teeth Bone Muscle Fat Gas
23
Q
Increased grid ratio = _______ contrast (less scatter)
A
Increased
24
Q
Decreased grid ratio = _______ contrast (more scatter)
A
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
