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WorksheetsPhysics 2 week 2 test 2
Total questions: 59
Worksheet time: 30mins
Digital radiography was first introduced by ____________.
GE in 1998
Fuji in 1981
Kodak in 1975
DuPont in 1965
Computed radiography screens respond to radiation with___
fluorescence
electron emission
photostimulable luminescence
biological phosphorescence
A photostimulable phosphor in a metastable state will emit light ____________.
immediately
when stimulated by light
immediately and when stimulated by light
immediately, when stimulated by light, and over time
Europium is the ____________ of the photostimulable phosphor.
image buffer
scintillator
phosphor
activator
The computed radiography cassette is called a(n) ____ receptor.
optical
imaging
laser
thermoluminescent
6. The photostimulable phosphor screen is handled in a _______.
cassette
envelope
tray
box
The computed radiography reader is made up of ____________, _______, and ______ modules.
mechanical; chemical; optical
chemical; optical; computer
mechanical; optical; computer
mechanical; chemical; computer
The four steps of creating an image with computed radiography are __________.
metastable state, stimulate, read, and erase
erase, stimulate, metastable state, and read
read, erase, stimulate, and metastable state
metastable state, read, erase, and stimulate
Following the laser stimulation of the photostimulable phosphor, the excited electrons are ____________.
completely stabilized
mostly stabilized
still excited
completely removed
The laser is one of the __________ features of the computed radiography reader.
computer
chemical
Optical filters are used to filter out the _ _____light and allow the _______ light to reach the photodetector.
stimulating; emitted
emitted; stimulated
emitted; monochromatic
stimulating; monochromatic
The output signal from the photostimulable phosphor plate is converted from analog to digital by the
optical system
computer controls
photodetector
drive mechanism
The principal source of noise in computed radiography is___
scatter radiation
background radiation
computer noise
phosphor scatter
With computed radiography the contrast is.
controlled by kVp
controlled by mAs
constant regardless of radiation exposure
impossible to change
The computed radiography image has_______________
narrow exposure latitude
wide exposure latitude
improved contrast resolution
wide exposure latitude and improved contrast resolution
The laser beam must be less than 100 μm in diameter in order to maintain.
consistent beam shape
smooth image edges
high spatial resolution
high speed
________ is prevented by flooding the erased imaging plate with bright light.
Image fog
Noise
Overexposure
Ghosting
Computed radiography imaging produces __________ gray levels.
30
100
10,000
1,000,000
The digital imaging plate can sit for some time after the erase cycle.
True
False
IPs should be used soon after the erase cycle has been completed.
True
False
Digital radiography is best described by which three elements?
Coupling, receptor, collection
Capture, signal, receptor
Collection, capture, receptor
Capture, coupling, and collection
In digital radiography, the visible image results when the ____________ is scanned by a laser beam.
storage capacitor
thin-film transistor (TFT)
photostimulable phosphor (PSP)
pixel detector
In digital radiography, the brightness of the image is determined by ____________.
pixel values
Hounsfield units
automatic brightness control
film contrast
In CR, the capture element is the ____________.
photostimulable phosphor (PSP)
thin-film transistor (TFT)
charge-coupled device (CCD)
scintillation phosphor
Scanned projection radiography was developed as a complement to ____________.
plain film radiography
computed tomography
magnetic resonance imaging
nuclear medicine
What is the most recent development in digital radiography image receptors?
Fanned x-ray beams
Linear array radiation detectors
Photostimulable phosphors
Direct capture solid state devices
Digital radiography first began to be used in clinical settings in the _____
1960s
1970s
1980s
1990s
In digital radiography, spatial resolution is improved with increased _____
field of view
Hounsfield units
pixel size
matrix size
The dynamic range determines the degree of ___ in the image.
contrast resolution
spatial resolution
motion blur
sensitivity
Spatial resolution is determined by the ratio of ___ to _____
matrix size; field of view
field of view; matrix size
bit depth; field of view
field of view; dynamic range
Scanned projection radiography differs from conventional radiography in the lack of _____________________________.
patient motion
spatial resolution
contrast resolution
scattered x-rays
The primary limitation of fanned beam radiography is_______________
reduced spatial resolution
long scanning time
low contrast resolution
shortened dynamic range
Computed radiography uses for latent image formation.
thin film transistors
photosensitive silicon chips
photostimulable phosphor
semiconductor material
Conventional x-ray tubes and image receptors are used with_____radiography systems.
computed
scanned projection
direct capture
All of the options are correct
One advantage of DR over scanned projection radiography is:
rotating x-ray tube
shorter exposure time
rotating detector array
fan x-ray beam
Digital radiography is best described by three elements—capture, archiving, and storage.
True
False
The CCD has high sensitivity to x-ray exposure and a very narrow dynamic range.
True
False
CsI/CCD is an indirect DR process by which x-rays are converted first to light and then to an electronic signal.
True
False
CsI/a-Si is an indirect DR process by which x-rays are converted first to light and then to an electronic signal.
True
False
Spatial resolution in DR is pixel unlimited.
True
False
Fluoroscopy was developed so that radiologists could view __________ images.
static
dynamic
magnified
darkened
What is the milliamperage used during fluoroscopy?
£100 mA
£50 mA
£5 mA
£1 mA
The image intensifier improved fluoroscopy by increasing image _____________.
brightness
resolution
magnification
contrast
Image intensified fluoroscopy is performed at illumination levels similar to.
star gazing
darkened theaters
night driving
radiograph viewing
Visual acuity in the eye is greatest at the __________, where _____ are concentrated.
retinal periphery; cones
fovea centralis; cones
retinal periphery; rods
fovea centralis; rods
The ability of the eye to detect differences in brightness levels is termed____.
visual acuity
scotopic vision
photopic vision
contrast perception
With image intensification the light level is raised to_vision.
photopic
scotopic
night
twilight
X-rays that exit the patient and enter the image intensifier first interact with the_ _____
output phosphor
input phosphor
photocathode
anode
Output phosphor of the image intensifier is composed of___.
cesium iodide
antimony
zinc cadmium sulfide
graphite
The input phosphor converts _______ _______ to _______.
x-rays; electrons
light; electrons
electrons; light
x-rays; light
The __________ in the image intensifier emits electrons when it is stimulated by light photons.
input phosphor
output phosphor
photocathode
electron gun
The number of light photons emitted within the image intensifier is __________ to the amount of x-ray photons exiting the patient.
equal
unrelated
inversely proportional
directly proportional
The kinetic energy of photoelectrons in the image intensifier is greatly increased by the __________.
mAs of the exposure
potential difference across the tube
cesium iodide at the input phosphor
zinc cadmium sulfide at the output phosphor
Light produced at the output phosphor of the image intensifier has been increased __________ times in intensity.
5 to 10
20 to 35
50 to 75
100 to 300
Electrons hit the __________ after exiting the anode.
output phosphor
input phosphor
cathode
grid
The__is the product of the minification gain and the flux gain.
horizontal resolution
brightness gain
contrast resolution
flux gain
The ratio of x-rays incident on the input phosphor to light photons exiting the output phosphor is called____gain.
magnification
minification
brightness
flux
The capability of an image intensifier to increase the illumination level of the image is called its____.
flux gain
conversion factor
brightness gain
veiling glare
An image intensifier tube is identified by the diameter of its____.
input phosphor
glass housing
output phosphor
focusing lenses
