3. Radiographic Film Flashcards
(93 cards)
1
Q
conventional image
receptor
A
Radiographic Film
2
Q
the medium that
records the image
A
Radiographic Film
3
Q
Radiographic Film has 2 main parts:
A
base and emulsion
4
Q
Radiographic Film is approximately
A
150-300µm
5
Q
Radiographic Film layers
A
SEAF
- Supercoat
- Emulsion
- Adhesive layer
- Film base
6
Q
primary purpose is to
provide a rigid structure
onto which the emulsion can be coated
A
Base
7
Q
reduces eyestrain and fatigue, enhancing radiologists’ diagnostic
efficiency and accuracy
A
Dye
8
Q
Radiographic Film: Base was originally made of
A
glass plates
9
Q
replaced glass plates but
was flammable, resulted in severe hospital fires during the 1920s and early 1930s
A
Cellulose nitrate
10
Q
similar to cellulose
nitrate but not as flammable;
“safety base”, was introduced in 1920
A
Cellulose triacetate
11
Q
became base of choice in the early 1960s because of its superior dimensional stability
A
Polyester
12
Q
Heart of the radiographic film
A
Emulsion
13
Q
consists of a homogenous mixture of
gelatin and silver halide crystals; 3-5µm
A
Emulsion
14
Q
is clear and porous and serves to
hold the crystals in place
A
Gelatin
15
Q
Radiographic Film: Emulsion active ingredient
A
Silver halide crystal (98% Silver Bromide, Silver Iodide)
16
Q
Tabular; 0.1 µm thick, 1µm in diameter
A
Emulsion
17
Q
Sensitivity center (photoelectrons \+ silver ions) = latent image center
A
Silver sulfide
18
Q
TYPES OF FILM
A
- Screen-Film
- Direct-Exposure Film
- Mammography Film
19
Q
this type of film uses intensifying screens
A
Screen-Film
20
Q
depends on size and
distribution of crystals
A
Contrast (Screen-Film)
21
Q
small grains relatively uniform in size
A
High-contrast emulsion (Screen-Film)
22
Q
large
grains that vary in sizes
A
Low-contrast emulsion (Screen-Film)
23
Q
is the sensitivity of the screen-film combination to x-rays and light
A
Speed
24
Q
speed is principally a function of the concentration and the total number of silver
halide crystals
A
Direct-exposure film
25
silver halide grain size,
| shape, and concentration are the principal determinants of film speed
Screen-film
26
is the exposure of an emulsion caused by light from the opposite
radiographic intensifying screen
Crossover (Screen-film)
27
The crossover control layer has three critical
| characteristics:
(1) It absorbs most of the crossover light,
(2) it does not diffuse into the emulsion but remains as a separate layer,
(3) it is completely removed during
processing
28
correctly matching the color sensitivity of the film to the color emission of the
intensifying screen
Spectral Matching
29
the color of light produced by a particular intensifying screen
Spectral emission
30
emit blue and blue-violet light
Calcium Tungstate
31
emit ultraviolet, blue,
| green, and red
Rare Earth Screens
32
the color of light to which a particular film is most sensitive
Spectral Sensitivity
33
green sensitive film
Orthochromatic film
34
sensitive to entire visible
| light spectrum
Panchromatic film
35
provide enough light to illuminate the darkroom
| while ensuring that the film remains unexposed
Safelights
36
Safelights ____ bulb, no closer than ____ from work surfaces
15W,
| 3-4ft
37
amber safelights (550nm)
Blue sensitive film
38
red filter (600nm)
Green sensitive film and Blue sensitive film
39
manufactured for use without intensifying screens
Direct Exposure Film
40
thick emulsion with high concentration of silver halide crystals
Direct Exposure Film
41
single-emulsion film designed to be exposed with a single
| intensifying screen
Mammography Film
42
Mammography Film uses
green-emitting terbium-doped gadolinium oxysulfide screens with green-sensitive film
43
Reflections at boundaries between film
| emulsion, film base, intensifying screens, and cassette surfaces
halation
44
undesired marks or spurious images that
| sometimes appear on processed radiographs
Artifacts
45
Heat and Humidity - stored at temperatures of _____
| and a relative humidity of ____
55-75° F (13-24°C),
| 30-60%
46
The fog level for unprocessed film is approximately
2 μGya (0.2 mR)
47
In most x-ray film, the emulsion is coated on both sides; therefore, it is called
double-emulsion film
48
Between the emulsion and the base is a
thin coating of material called the _____, which
ensures uniform adhesion of the emulsion to the base.
adhesive layer
49
allows the emulsion and the base to
| maintain proper contact and integrity during use and processing
adhesive layer
50
The emulsion is enclosed by a protective covering of gelatin called the
overcoat
51
protects the emulsion from scratches, pressure, and contamination
during handling, processing, and storage
overcoat
52
is the foundation of radiographic film
base
53
flexible and fracture resistant to allow easy handling but is rigid enough to be snapped into a view box
base
54
The base of radiographic film maintains its size and
shape during use and processing so that it does not contribute to image distortion. This property of the base
is known as _____
dimensional stability
55
is of uniform lucency and is nearly transparent to light
base
56
Radiologists used to refer to radiographs as
x-ray plates
57
is more resistant to
| warping from age and is stronger than cellulose triacetate, permitting easier transport through automatic processors
Polyester
58
are thinner than triacetate bases (≈175 µm) but are just as strong.
Polyester
59
It is the material with which x-rays or light photons from
| radiographic intensifying screens interact
Emulsion
60
The arrangement of atoms in the crystal is
cubic
61
It is clear, so it
transmits light, and it is sufficiently porous for
processing chemicals to penetrate to the crystals of silver
halide
Emulsion
62
Types of Film Used in Medical Imaging
1. Intensifying screen
2. Laser printing
3. Copy or duplicating
4. Dental
5. Radiation monitoring
6. Dry transfer
63
Intensifying screen emulsion
Two
64
Laser printing emulsion
Single with antihalation
| backing
65
Copy or duplicating emulsion
Single with antihalation
| backing
66
Dental emulsion
Two packed in sealed
| envelope
67
Radiation monitoring emulsion
Two packed in sealed
| envelope
68
Dry transfer emulsion
One
69
Blue or green sensitive
Intensifying screen
70
Matches laser used (≈630 nm)
Laser printing
71
Pre-exposed
Copy or duplicating
72
Has lead foil to reduce back scatter
Dental
73
One emulsion can be
| sloughed off to increase OD scale
Radiation monitoring
74
Thermally sensitive
Dry transfer
75
General radiography
Intensifying screen
76
attached to
CT, MRI, ultrasonography,
and so on
Laser printing
77
Duplicating radiographs
Copy or duplicating
78
Dentistry
Dental
79
“Dry” printers
Dry transfer
80
SILVER HALIDE CRYSTAL FORMATION
AgNO3 + KBr → AgBr ↓(precipitated) + KNO3
81
The type of
imperfection thought to be responsible is a chemical contaminant, usually _____, which is introduced
by chemical sensitization into the crystal lattice, usually at or near the surface.
This contaminant has been given the name
silver sulfide,
| sensitivity center
82
During exposure, ______ are attracted to these sensitivity centers, where they combine to form a latent image center of metallic
silver
photoelectrons and silver
| ions
83
The size and concentration of silver halide crystals primarily affect
film speed
84
mammography, video recording, duplication, subtraction, cineradiography, and dental radiology
nonscreen film and special application film
85
The contrast of an IR is _____ to its exposure latitude, that is, the range of exposure techniques that produce an acceptable
image
inversely proportional
86
are more sensitive than
| small-grain emulsions
Large-grain emulsions
87
This more efficient use of silver in the emulsion is called the _____ of the emulsion
covering power
88
Crossover is reduced by adding a dye to the
| base; reduces crossover to near zero; this is called a
crossover control layer
89
Tabular grain emulsions reduce ____ because the covering power is increased, which relates not only to light absorption from the screen (which is increased) but also to light transmitted through the emulsion to cause crossover (which is reduced)
crossover
90
absorbing dye is an ____ coating
antihalation
91
Radiographic film should be stored at temperatures lower than approximately
20°C (68°F)
92
is the dull, uniform OD that appears if
the film has been inadvertently exposed to light, x-rays,
heat, or humidity
Film fog
93
the range of exposure techniques that produce an acceptable
| image
exposure latitude
