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Physics - Common Equipment > Chapter 15 > Flashcards

Chapter 15 Flashcards

(100 cards)

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1
Q

When was the first fluoroscope invented and by who?

A

1896 by Edison

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2
Q

1st fluoroscope was made with what type of screen?

A

Calcium tungstate

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3
Q

When was the image intensifier introduced?

A

1950s

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4
Q

Image intensifiers allowed for images to be _______ viewed through mirror optics and later, television monitors

A

Indirectly

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5
Q

What mA is used in fluoroscopy vs conventional x-ray?

A

Fluoro: .5 - 5 mA
Tradiational: 50 - 1200 mA

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6
Q

Benefits of low mA used in fluoro

A

Can be used for longer durtation with reduced risk of injury to the patient

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7
Q

Fluoro control panels are fitted with a timer that discountinues exposure at the __ minute mark

A

5 minute

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8
Q

What is an image intensifier and what does it do?

A

An electronic vacuum tube that converts the remnant beam to light, and then into electrons, then back into light

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9
Q

5 basic parts of the image intensifer

A

Input phosphor
Photocathode
Electrostatic focusing lenses
Accelerating anode
Output phosphor

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10
Q

The intensified light exiting the output phosphor is converted into ____________

A

electronic signal

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11
Q

Input phosphor is typically made of _____ and bonded to the _______ surface of the intensifier tube

A

Cesium iodide
Curved

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12
Q

Which phosphor is larger?

A

Input

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13
Q

What happens when radiation strikes the cesium iodide of the input phosphor?

A

Light is emitted

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14
Q

The photocathode is made of ________

A

cesium and antimony

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15
Q

After being exposed to light, the photocathode emits ______

A

electrons

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16
Q

What is the process called when the photocathode emits electrons?

A

Photoemission

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17
Q

The photocathode is curved in a way that directs the emitted electrons in same the direction, through the ____________

A

electrostatic focusing lenses

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18
Q

The focusing lenses are __________ charged plates

A

Negatively

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19
Q

The negative charge of the focusing lenses __________ the electrons in a focused direction, towards the ________

A

Repels
Accelerating anode

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20
Q

The purpose of the accelerating anode is to:

A

Direct the electrons at a consistent rate towards the output phosphor

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21
Q

The anode is supplied with a constant electric potential of:

A

25 kV

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22
Q

After exiting the accelerating anode, electrons stike the _______________

A

output phosphor

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23
Q

Output phosphor is made up of ___________

A

Silver-activated zinc cadmium sulfide

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24
Q

The output phosphor ________ electrons and coverts them into light

A

Absorbs

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25
The light absorbed by the output phosphor is converted into
Electric signal
26
The ability of an image intensifier tube to convert radiation into light is referred to as
Brightness gain
27
Brightness gain =
Flux gain x minifiation gain
28
The ratio of the number of light photons at the output phosphor to the number of x-ray photons at the input phosphor
Flux gain
29
Flux gain represents the:
Systems efficiancy
30
The expression of how much an image is minified, meaning made smaller, from the input phosphor to the output phosphor
Minification gain
31
The expression of luminance at the output phosphor divded by the input exposure rate
Conversion factor
32
As the intensifier ages, it will slowly ________ it's ability to intensify
Lose
33
Function that maintains the overall appearance of the image by adjusting kVp and mA as needed
Automatic Brightness Control (ABC)
34
When operating in magnification mode, ________ to the focusing lens within the intenisifier is ________
Voltage Increased
35
What happens to the focal point when mag mode is being used
Shifts the focal point farther from the output phosphor (similar concept to OID)
36
Mag mode increases:
Spatial resolution and patient dose
37
Unequal magnification creates a form of shape distortion known as:
Pincushion appearance
38
The loss of brightness around the edges of the image
Vignetting
39
Television cameras used to display images included either:
Camera tubes or CCD
40
Camera tubes are the same diameter as the:
Output phosphor
41
Most common camera tube is the:
Vidicon tube
42
How is the vidicon tube connected to the output phosphor
Fiber optics or optical lenses
43
Vidicon tube is a _____ tube contained in a ______, which maintains a vacuum
Diode Glass envelope
44
_____ end of the vidicon tube consists of an electron gun and control grid
Cathode
45
The electron gun in the vidicon tube provides a continous steam of _______, the control grid forms the stream into a _________
Electrons Beam
46
Center of the vidicon tube contains coils that provide:
Alignment, focus and deflection
47
What is the purpose of the coils in the vidicon tube?
Accelerate and control the electron beam
48
The coils in the vidicon tube cause the beam to follow a specific pattern called a:
Raster pattern
49
______ end of the vidicon tube consists of a face plate, signal plate, and target
Anode
50
The signal plate in the vidicon tube is a __________ material that conducts electricity
Graphite
51
The target in the vidicon tube is a photoconductive layer made of:
Antimony trisulfide
52
In plumbicon tubes, the target is made of:
Lead oxide
53
The target in the plumbicon tubes acts as a __________ or a _________ depending on if it's illuminated
Conductor or insulator
54
When using CCD in place of camera tubes, a series of __________ capacitors are used, with each capactior representing an individual pixel in the image
Metal oxide semiconductors
55
When using CCD, each pixel is made of photosensitive material that dislodges __________ when stimulated by light
Electrons
56
When using CCD, electrodes between each pixel, called ___________, are charged in sequence, which moves the signal down the row, where it is ultimately transferred to capacitors
Row gates
57
CCD TV cameras are _____ sensitive to a wider range of light intensity
More
58
Are fiber optics or optical lens systems more durable?
Fiber optics
59
Which type of connection, fiber optics or optical lens, allows for spot films?
Optical lens
60
TV monitor converts electrical signal from camera tubes or CCD back into:
Visible images
61
Older fluoro units used what type of monitors?
Cathode Ray Tube (CRT)
62
How did CRT monitors function?
Like camera tube systems, but in reverse
63
Typical monitors are called ______ line systems
525
64
High resolution monitors have ___ lines per frame
1024
65
Spot films are when a fluoro unit is used to take ______ images
Static
66
Film cameras use much _____ radiaiton than cassette-spot film systems
Less
67
Earlier versions of fluoro added in an ADC and computer between the camera tube and monitor. The ADC took the analog signal and converted it to:
Digital signal
68
Two forms of FPD systems
Indirect capture Direct capture
69
The photodetector in indirect capture systems is:
Amorphous silicon
70
Direct capture systems use:
Amorphous selenium
71
Indirect capture uses scintillators that are made of either ________ or _______
Cesium iodide or gadolinium oxysulfide
72
In fluoro, FPDs use a ____________ to erase the detector between each individual frame
Light-emitting diode array
73
Current dynamic systems are capable of capturing up to _____ frames per second
60
74
The last frame captured is held for viewing on the monitor
Last hold image (LHI)
75
Collimation lines are visible on monitor
Virtual collimation
76
Reduces overall dose and noise by averaging multiple frames together
Frame averaging
77
Prebuilt algorithms that are meant to be used with specific body parts
Anatomic programs
78
Automatically adjusts technical factors to maintain optimum exposure levels
Automatic exposure rate control (AERC)
79
AERC can automatically adjust:
mA kVp Filtration Pulse width
80
Electronic magnification is the selection of a ______ FOV
Smaller
81
At _____ pulses per second, the dose is about the same as continous fluoro
30
82
Amount of pulses that occur each second
Pulse rate
83
Length of each pulse
Pulse width
84
The amount of kinetic energy released in matter
Air Kerma
85
Max air kerma rate for fluoro
88 mGy/min
86
Used to measure exposure in air
Dose-area product (DAP)
87
Same as DAP - product of total air kerma and the area of the beam as it enters the patient
Kerma air product (KAP)
88
Type of monitors that offer superior resolution and displayed brightness
Liquid crystal display (LCD)
89
In LCD, the crystals within the crystal layer are ______ shaped and _________ liquid
Rod Semi
90
In LCD, when ___________ is applied, the crystals organize into configurations that either block or allow light to pass through
Electric current
91
In LCD, a layer of _____ controls each individual pixel in the display
TFTs
92
Plasma monitors use _________ instead of a liquid crystal layer
Thin layer of pixels
93
In plasma displays, each pixel is made up of __ different subpixels, each filled with _____ and ______
3 Neon and xenon gas
94
In plasma, each of the subpixels are coated with a different phosphor that produces:
red, green or blue light
95
In plasma, the pixel layer is sandwiched between two _________ layers
Dielectric
96
In plasma, when electricty is passed through the dielectric layers, the gas within each subpixel is:
Ionized
97
In plasma, the liberated electrons release:
UV radiation
98
In plasma, UV radiation stimulates the phosphors while producing:
Visible light
99
Source-to-skin distance shoud be no less than _____ cm on for stationary fluoro units
38
100
Source-to-skin distance should be no less than _____ cm for mobile units/c-arm units
30

Physics - Common Equipment (7 decks)

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