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40 Cards in this Set

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The ability to display two or more closely spaced objects as separate images
Spatial Resolution
The size of the relevant image displayed on the cathode ray tube (CRT)
FOV
Through application of software programs, possible to assign pixels a different gray scale value
Gray scale enchancement
Mathematically measures image against original object: 0 represents no image, 1 represents perfect image
Modulation transfer function
Aberrant movements of electrons in electonic equipment seen as flashes of light (snow) that degrades the image
Electronic noise
Analog signal sampled twice per cycle by ADC to gain accurate digital signal
Nyquist Criterion
Displaying small differences in subject contrast
Contrast resolution
The number of shades of gray assigned to the pixles
Dynamic range
Determines the number of density values available in each pixle. If affects density (brightness) and contrast of system and is controlled by the ADC
Pixle Depth
Loss of image quality caused by random variations in the number of photons striking the IR
Quantum Mottle
The number of densities from black to white on the x axis, the number of each density on the y axis
Histogram
A pre-set "ideal histogram" for each projection
Look up table (LUT)
CR provides optimal brightness and enhanced contrast
Normalization
A high "S" number indicates a need to move the center point (Sm) over ____.

a. more
b. less
a. more
"S" values greater than 400 indicates _______________.

a. Overexposure
b. Underexposure
c. Perfect exposure
b. Underexposure
"S" values greater than 400 will demonstrates _________.

a. Quantum Mottle
b. Improved MTF
c. Lose of contrast
a. Quantum mottle
Three different type of reference histogram models used for LUT's include one that must have a direct exposure "spike" to locate S2. This is a:

a. Type 1
b. Type 2
c. Type 3
a. Type 1
Histogram shape is NOT influenced by...

a. Type of exam
b. Patient positioning
c. mAs
d. Type of generator
c. mAs
Which of the following does NOT use thin film transistors (TFTs).

a. Indirect photostimuable phospher imaging plate system
b. Direct selenium flat panel imaging plate system
c. Indirect silicon flat panel imaging plate system
a. Indirect photostimulable phospher imaging plate system
CR or DR?
 Uses cassettes- more familiarity for technologists
 More adaptability for positioning and technique
Computed Radiography
CR or DR?
 Direct hookup to the computer- no cassettes
 Attached to a table/chest bucky, contains a grid, and
AEC sensors
 Flexibility of positioning limited
 No ability to split fields for multiple views
 Increased patient throughput
 Higher detective quantum efficiency (DQE)
Digital Radiography
Does comptued or digital radiography use Indirect Photostimulable
Phosphor Imaging Plate
Systems (Computed
Radiography)?
Comptued Radiography
The_______ _____ ______ is
designed to look and act to perform many
functions of standard cassette
Computed Radiography
The computed radiographic (CR) cassette....

a. Comes in many of the same sizes as standard
film cassettes
b. Can be used with tabletop or bucky
c. Can be used with manual or AEC techniques
d. All of the above
d. All of the above
Name some features of a CR cassette
 Aluminum or plastic
 Low absorbing carbon front
 Back panel has lead foil- backscatter
 Has a memory chip in one corner to download
information on the exam and patient
 Front and back lined with felt to reduce static
electricity and cushion plate
PSP stands for...
Photostimulable phosphor
IP stands for...
Imaging plate
How thick is an CR plate?
1mm in thickness
Which layer in a CR plate is supported by a firm base and protected by a thin plastic layer?
The active phosphor later
Name the following Layers
The ______ layer and/or __________ layer grounds static charge; reverses light emissions
Refletive and or conductive layer
What type of emulsion must be facing forward?
Single emulsion
What are some common phosphers?
Europium activated barium fluorohalides
What is the average energy (keV) of 80 KVP beam?
35
True or false: Digital screens will absorb more low energy scatter thus the plate is senesitive
True
Since Photostimulable phosphor (PSP) absorb more low energy radiation
than radiographic film they are more........
More sensitive to scatter both before and
after exposure than radiographic film. Thus, Masking is needed to achieve optimal images
In a Latent image, where are the electrons stored?
Electron pattern is stored in active layer of
exposed IP
How is a latent image made?
 Energy transferred to photoelectrons
 Several photoelectrons liberated
 Liberated electrons have extra energy
 Blue-violet light given off by fluorescence
 More electrons freed by photoelectrons
In a latent image Fluorohalides absorb beam through ____________ interactions
Photoelectric
In a Latent Image Production,
Some electrons get trapped in the fluorohalides to create holes at the Europium site, this is called...?
Electron Holes