TEST 1 Flashcards
1
Q
image receptor
A
medium that transforms the xray or useful beam into a visible image
2
Q
useful beam (primary beam)
A
xrays emerging from the tube
3
Q
remnant beam
A
xrays that remain after the useful beam exits the patient
4
Q
3 types of image receptors
A
- film w/ intensifying screens
- imaging plates (CR)
- flat panel detectors (DR)
5
Q
film
A
film cassette contain an intensifying screen which turns energy from xray into visible light to expose film
6
Q
latent image
A
invisible image before its processed into an image we can see
7
Q
manifest image
A
image after it has been processed so that we are able to see it
8
Q
CR (computed radiography)
A
uses loaded cassette consisting of imaging plate containing photostimulable phosphor (PSP) when hit by xray they’ll emit a light to create the image
9
Q
DR (direct readout digital radiography)
A
utilize flat panel of detectors to absorb exit radiation
10
Q
2 types of film
A
- direct exposure film (non screen film)
2. screen film
11
Q
direct exposure film
A
used without intensifying screen
longer developing time
greater exposure
limited use in medical imaging as exposure is too great to patient
12
Q
screen film
A
most widely used film
used with 1 or 2 intensifying screens
sensitive to light
less development time
13
Q
characteristics of film
A
contrast
latitude
speed
14
Q
contrast is inversely proportional to its exposure latitude
A
more exposure latitude less contrast
15
Q
exposure latitude
A
range of exposure factors that will reproduce an acceptable radiograph
16
Q
higher kVp allows
A
more latitude (greater margin for error)
17
Q
lower kVp….
A
less margin for error
18
Q
speed
A
the degree to which the emulsion is sensitive to xrays or light
19
Q
2 factors affecting speed
A
number of silver halide crystals
size of silver halide crystals
20
Q
the more silver halide crystals
A
the faster
21
Q
the larger the silver halide crystals
A
the faster
22
Q
the faster the speed of film
A
the less radiation dose to the patient
23
Q
speed/mAs conversion formula
A
mAs1/mAs2 = IR speed2/ IR speed 1
24
Q
fast speed system (400)
A
used for big body parts
thorax, abdomen, pelvis, skull, contrast media
25
slow speed system (100)
usually used table top
extremities, madible, nasal bones
good detail but greater pt. dose
26
what does the processor consist of
```
transport system
replenishment system
recirculation
temperature control
drying
```
27
transport system
moves film through the developer, fixer,washer and dryer of the processor
28
the transport system consists of
transport racks
crossover networks
drive system
29
what are the tanks in the processor
developer
fixer
washer
made of stainless steel to prevent corrosion
30
feed tray
flat metal surface edged on both sides
| allows for correct alignment of film
31
True or False
| you must alternate film from side to side to ensure proper wear of rollers
True
32
entrance roller assembly
rollers covered with rubber
| keeps film in a straight path
33
audible signal
indicates the film is through
34
transport rollers
move film through chemical tanks and dryer assembly
| sometimes positioned parallel, sometimes staggered
35
turnaround assembly consists of
master roller
planetary roller
guide shoe
helps the film turn around to come back up again
36
turnaround roller AKA master roller
at the bottom of roller assembly
turns film from moving down to moving up
also called deep rollers
37
planetary roller
smaller rollers positioned on either side of the master roller
aid in proper alignment of the film
helps the film from slipping out
38
guide plates (guide shoes)
curved metal plates on either side of master roller
| guide film through roller assembly
39
crossover roller
moves film from one tank to another and finally into the dryer
between two tanks
40
true or false
| the space between the crossover rollers are extremely tight to create a squeegee effect to remove excess liquid
TRUE
41
drive system
power that moves the rollers around
42
drive system speed
speed is set to transport film from entrance roller to receiving bin within 45-90 seconds
varies depending on type of film
43
standby control
electric circuit shuts off power when processor is not in use
44
replenishment system
replacement of fresh chemicals after loss of chemicals during processing
both developer and fixer need to be replenished
45
proper film entry
short side of film up against feed tray guide
46
true or false
| over replenishment of developer increases density and decreases contrast
True
47
under replenishment of developer
causes decreased density
48
under replenishment of fixer
results in brown stains
49
2 ways to replenish chemicals
1. volume replenishment
| 2. flood replenishment
50
volume replenishment
used for high volume workload
51
flood replenishment
used for smaller facility not as much patient volume
| replenishment of solutions at timed intervals
52
re-circulation system
agitates solutions
mixes old and new chemistry
filters solution
stabilizes temperature
53
agitation solution
circulates the solutions in each tank by pumping solution out of one portion of tank and returning it to a different location in the same tank
54
mixing old and new chemistry
its necessary to mix them to maintain constant temperature
55
re-circulation filter
removes impurities as the developer solution is re-circulated
56
temperature control
maintaining constant temp of solutions has an effect on radiographs
57
increased developer temp =
increase density (too dark)
58
decreased developer temp =
decreases density (too light)
59
2 types of temperature control
1. immersion heater
| 2. heat exchanger
60
immersion heater
a heating coil immersed in the bottom of the tank
| brings in cold water and heater warms up the water
61
heat exchanger
most common
| uses thermostat to heat the developer
62
average temp of developer
33-35 degrees C
| 92-96 degrees F
63
wash water temp
3 degrees C or 5 degrees F lower than the developer temp
64
drying system
hot air is blown onto both sides of film as it moves through dryer
65
when films are damp it is usually because
a lack of hardener in the fixer or the water is saturated with chemicals
66
artifact
any unwanted image on a radiograph
67
plus density artifact
darker image
| ex: fingernail scratch
68
minus density artifact
lighter image, white spot
| ex: moisture on a finger
69
artifacts can be classified as:
1. exposure artifacts
2. processing artifacts
3. handling and storage artifacts
70
exposure artifacts
associated with the manner in which the radiographer performs the exam
caused by the radiographer
ex: motion, improper positioning, double exposure, etc.
71
processing artifacts
produced during processing
| most are pressure type caused by transport system
72
processing artifacts:
| emulsion pickoff and gelatin buildup
caused by dirty or warped rollers
| deposits sludge on film
73
processing artifacts:
| curtain effect
excess chemistry runs down the edge of the film
74
processing artifacts:
| chemical fog
caused by improper or inadequate processing chemistry
75
guide-shoe marks
occurs when guide shoes in turn around assembly are improperly positioned or out of line causes the emulsion to scrape off. white lines
76
pi lines
caused by dirt or chemical stain on roller which affects the emulsion
occur at 3.1416 inch intervals
77
wet pressure sensitization
caused by irregular or dirty rollers
78
dichoric stain
chemical stain caused by improper or inadequate processing chemistry
can appear yellow, green, blue, or purple
79
handling and storage artifacts
rough handling, image fog due to temp/humidity, film bin not shielded, etc.
80
handling artifacts:
| scratches
caused by pressure on the feed tray
81
handling artifacts:
| pressure marks
caused by kinking of the film
82
2 most common types of static artifacts
1. tree static
| 2. smudge static
83
smudge static
when there's very dry conditions
84
tree static
looks like branches on a tree
85
silver recovery
the removal of silver from the used fixer solution
the fixer gets saturated with silver so the processor constantly replenishes the chemicals
silver ions are reclaimed through silver recovery process
86
fixer
removes unexposed silver halide from film therefore contains a high concentration of silver
87
quality control
cleaning the processor
clean racks weekly
scheduled maintenance
88
daylight processing
alternative processing
| film automatically extracted, processed and cassette reloaded
89
processing
converts the invisible latent image into the visible manifest image
90
4 steps in processing
developing
fixing
washing
drying
91
amount of time to process a single piece of film
45 seconds - 3.5 minutes
| most processing times = 90 seconds
92
developer main purpose
turn exposed silver crystals into metallic silver
| aka to make up the image
93
developer consists of
```
developing (reducing) agents
accelerator (activator) agents
restrainer
preservative
hardener
solvent
```
94
developing/reducing agents
reduce exposed silver halide to metallic silver
| adds electrons to exposed silver halide
95
developer chemicals
hydroquinone
| phenidone and metol
96
hydroquinone
creates higher densities (black)
| acts slow
97
phenidone and metol
creates lower densities (grays)
| acts fast
98
hydroquinone and phenidone are synergistic
meaning they work together
| this is what shapes the characteristic curve
99
characteristic curve
a graph of the optical density
shows the relationship between the exposure to a film and the amount of light that can be transmitted through that film
shows whether the film was under or over developed
100
also in the developer is a wetting agent
AKA water
| to soften and swell the emulsion
101
accelerator/activator agents
also called buffering agents
| maintains the pH of the developer
102
what chemical is the buffering agent
sodium carbonate
103
restrainer
keeps unexposed crystals from the developing agent
| without the restrainer we would get development fog
104
development fog
development of unexposed silver halide
105
what chemical is the restrainer
potassium bromide
106
preservative
preserves the developer by decreasing oxidation of the developer solution
107
aerial oxidation
reduction in chemical activity of developer by air
108
use oxidation
reduction in chemical strength as a result increased temp over a period of time
109
what chemical is the preservative
sodium sulfite
110
hardener
hardens emulsion which was originally softened by reducing agents
111
what chemical is the hardener
glutaraldehyde
112
what is the biggest problem in automatic processing?
insufficient hardener or glutaraldehyde
113
solvent
dilutes chemicals in developer
| the solvent is water
114
chemical fog
fog produced by chemical contamination of the developer
115
fixer
removes unexposed silver halide and makes the remaining image permanent
further hardens the emulsion
116
fixer consists of
```
activator
fixing (clearing) agent
preservative
hardener
solvent
```
117
activator
neutralizes the pH of emulsion and stops action of developer
118
what chemical is the activator of the fixer
acetic acid
119
fixing (clearing) agent
clears underdeveloped silver halide from the film
120
what chemical is the fixing agent of the fixer
ammonium thiosulfate
121
preservative of the fixer
protects the fixing agent from oxidation
| maintains chemical balance
122
what chemical is the preservative of the fixer
sodium sulfite
123
hardener of the fixer
further hardens the emulsion so the image becomes permanent
| makes it better for handling
124
what is the chemical of the hardener of the fixer
potassium aluminum
(aluminum chloride )
(chromium alum)
125
solvent of the fixer
dilutes the chemicals in the fixer to that chemicals function at correct level of activity
solvent = water
126
washing
removes fixer and developer solution from the surface of film
127
reticulation
when the temp changes too fast the emulsion may crack into many pieces
128
drying
the final process
forced hot air over both sides of film
removes 85-90% of moisture
129
drying temp
ranges from 120-150 degrees F
130
how long is an original radiograph stored
5-7 years
| mammography 10 years
131
storage temp
70 degrees F
