Test 2 Flashcards
0
Q
Photosensitive crystals in film are in the ________ layer
A
Emulsion
1
Q
T/F film base is made of Dacron
A
False (polyester)
2
Q
Dye is added to the _______ layer
A
Base
3
Q
T/F The sensitivity speck is required for black metallic to be deposited
A
True
4
Q
The undeveloped image is called the ________.
A
Latent image
5
Q
Stored film is sensitive to
- age
- Light
- Humidity
- All
A
- All
6
Q
Crystals are what shape
A
Flat triangular
7
Q
T/F Panchromatic film is not sensitive to the red spectrum
A
False
8
Q
T/F Film is most sensitive to x rays
A
False (light)
9
Q
The active layer of screens I the ________ layer
A
Phosphor
10
Q
T/F luminescence is caused by excitation
A
True
11
Q
______% of latent image is formed by light from intensifying screens
A
99
12
Q
Screen lag is caused by
- Fluorescence
- Luminescence
- Phosphorescence
- Two of the above
A
- Two of the above
13
Q
T/F film screen speed is always relative
A
True
14
Q
Film screen resolution is ultimately determined by
A
Screen phosphor size
15
Q
T/F Quantum Mottle is caused by too few photons
A
True
16
Q
Screen speed is controlled by
- Phosphor size
- Thickness of phosphor layer
- Concentration of phosphors
- All of the above
A
- All of the above
17
Q
Image artifacts maybe caused by
- Dust
- Scratches
- Foreign objects in cassette
- All
A
- All
18
Q
T/F small crystals = low resolution
A
False
19
Q
The developer component that creates density is
A
Reducing agents
20
Q
Developer action is controlled by
A
Time
Temp
Chemical activity
21
Q
T/F If reducing agents work too long te entire film will be black
A
True
22
Q
T/F developer has an alkaline PH
A
True
23
Q
When developer gives up electron to the air it is called
A
Oxidation
24
When mixing fixer always limit it to a two week supply
True
25
______ is most sensitive to contamination
Developer
26
_______ stops the action of the film turnin to black metallic silver
Fixer
27
Washing and drying are important to archiving films
True
28
A slow transport system will result in over developed films
True
29
________ rollers remove excess chemistry
Squeegee
30
10% of film cost can be regained by silver recovery
True
31
Longer processing times requires _________ temperature
Lower
32
The protective potion of radiographic film is made of ______
Gelatin
33
Three characteristics about the base of modern film
Firm
Flexible
Resistant to tears
34
The adhesive layer of film bonds the _______ to the _______
Base
| Emulsion
35
History notes that the first material used to construct film base was
Glass
36
The addition of gold-silver sulfide (as an impurity) to film during the formation or growing a silver-halides creates________
Sensitivity speck
37
Silver halides are suspended in the _______ of the ______
Gelatin
| Emulsion
38
When at least three _______ migrate to the negatively charged trap during latent image formation, small amounts of metallic silver will form
Silver atoms
39
Compare single and double emulsion film
Dbl emulsion is faster/more sensitive than single emulsion
Dbl emulsion potentially has twice the silver halide crystals
Single emulsion is used in mammography an fine detail radiography
40
The primary function of screens is to convert_________ to _______
X Ray photons
| Light
41
How do screens affect pt dose
Decrease pt dose
42
List four layers o an intensifying screen
Base
Reflective
Phosphors
Protective
43
Screen base is usually made of
Polyester plastic
44
The reflective layer of the screen is necessary due to the _______ nature of light emission in the phosphors
Isotopic
45
Dye is used in the _______ layer of the screen to absorb light emitted at wide angles and thus improve image sharpness/resolution
Reflective
46
The active layer of the screen is the ______ layer
Phosphor
47
Scratches that remove phosphor crystals rest in (white line/black line) artifacts on the radiographic image
White line
48
The phosphors need a (high/low) atomic number to increase the probability of xray photon interaction
High
49
Describe excitation
An inner shell electron absorbs the energy of an incoming x Ray photon, jumps up almost to another energy shell and then snaps back giving off light.
50
Two types of luminescence are
Fluorescence
| Phosphorescence
51
Instantaneous emission of light is
Fluorescence
52
Delayed emission of light also know as afterglow or screen lag is
Phosphorescence
53
Spectral emission is matching the light emitted from the _______ to the light sensitivity of the _____ to ensure maximum latent image
Screen
| Film
54
How can the tech correct for quantum Mottle
Increase mAs
55
Intensifying screens are
Thin sheets or layers of fluorescent materials
56
What happens to x Rays when they enter a radiographic cassette
Absorbed by the intensifying screen material and a portion is converted into light
57
How much more radiation would be necessary for an exposure without screens
100 times more
58
Absorption efficiency is primarily determined by
Screen material
Screen thickness
Photon energy spectrum
59
Bc of their fluorescence intensifying screen materials are often referred to as
Phosphors
60
What is the most significant effect of screens on image quality
Thickness
61
What causes image blur in relation to screens
The thickness and light transparency of the screen
62
Define crossover
Unabsorbed light from one side passes through the film base and exposes the emulation on the other side
63
Define halation
Reflections at boundaries between film emulsion film base intensifying screens and cassette surfaces
64
State the primary function o developer
To deposit enough black metallic silver at the latent image sites to permit a visible image
65
6 components in deleveper
Reducing agents-provide electrons to reduce silver to black metallic
Activator- maintains pH 10-10.5
Restrainer - restricts reducing agent
Preservative - reduces oxidation
Hardener - controls gelatin swelling and maintains unifor thickness
Solvent- water
66
List 5 components of fixer
Cleaning agent - bonds with unexposed silver halides and removes emulsion
Activator - maintains pH 4.0-4.5
Preservative- dissolves silver
Hardener - prevents scratches and abrasions
Solvent - water
67
4 Layers of film construction
Base
Adhesive
Emulsion
Supercoat
68
Film resolution/speed ; crystal size/ emulsion layer
⬆️ crystal size ⬇️ resolution ⬆️ speed
⬆️ emulsion layer ⬇️ resolution ⬆️speed
69
Layers of screen construction
Base
Reflective layer
Phosphor layer (crystals)
Protective coat
70
Resolution/speed relationship for screens
Inverse relationship
⬆️size ⬇️resolution ⬆️speed
⬆️thickness ⬇️resolution⬆️speed
⬆️consentration ⬆️resolution ⬆️️speed
