A _____ test tool is used to acquire data for an MTF curve.
bar pattern
As mAs is increased the signal to noise ratio is _____.
increased
As spatial frequency increases the object size _____ and the spatial resolution ____.
decreases; increases
Compared to CRTs, AMLCDs have _____.
better contrast,
less intrinsic noise,
better gray scale definition
DQE is _____.
Detector Quantum Efficiency
If an image receptor has a high probability of interacting with the x-ray beam, then it has a high ____.
DQE
If there were such thing as a perfect imaging system, the MTF would be equal to ___.
1
Image detail is also called _____.
spatial resolution
Of all radiographic imaging systems, _____ has the best contrast resolution.
computed tomography
Screen-film radiography has a dynamic range of ___.
1000
Spatial frequency is used to describe the quality of spatial resolution in terms of ____.
line pairs
The bit capacity of each pixel identifies the _____ of a digital imaging system.
dynamic range
The human visual system can distinguish ___ shades of gray.
30
The number of gray shades that an imaginging system can reproduce is called its ____.
dynamic range
The portion of useful image-forming x-rays is referred to as the _____.
signal
The two principal characteristics of a medical image are ____.
spatial resolution and contrast resolution
The use of an image receptor with _____ DQE can result in _____ patient doses.
high; lower
With digitial imaging, patient dose can be reduced by using higher ____ techniques.
kVp
The science of __________ is the study of the response of the human eye to light:
photometry
What is the basic photometric unit?
a lumen
The decreasing luminous intensity with increasing distance from the source of light follows ________:
the inverse square law
A digital display monitor is best viewed _______:
straight on
A liquid crystal is a material in a ________ state:
state between a liquid and a solid
Almost all digital images in medical imaging are viewed and interpreted on a ____________:
digital display device
A digital display device with higher megapixels has better spatial resolution...true or false?
True
Almost all medical flat panel digital display devices are __________:
monochrome liquid crystal displays
Medical flat panel display devices are identified by the __________:
number of pixels
An advantage to viewing the AMLCD screen is that the image quality is equally good viewed from any angle...true or false?
False
The ambient light at a digital image workstation should be ________:
near darkness
Pre-processing the digital image is done ______, and post-processing is done _______:
automatically; manually
Flatfielding is accomplished through automatic calibration images called _______ and _______:
offset images; gain images
Re-registering an image to correct for patient motion is done with _______:
pixel shift
A computation of the mean pixel value within a region-of-interest is performed for __________:
quantitative radiology
Post-processing includes all of the following except __________.
signal interpolation
_______ is corrected by the application of an offset voltage:
Image lag
PACS stands for ________:
Picture Archiving and Communication Systems
Which is not a part of PACS?
Film storage
Within a PACS network the secretarial workstation and the viewing workstation would both be called ________:
clients
The national standard for image transmission in teleradiology is the ________ format:
DICOM
Text data and email are generated at a _________ workstation in PACS:
radiology information system (RIS)
Image file size is determined by ________ size and gray scale:
matrix
What is the file size of an image with a 1026x1026 matrix and a 2.5 byte gray scale depth?
2.6 MB
A digital imaging system cannot resolve anything smaller than ______ pixel(s):
one
A system with a spatial resolution of 10 lp/mm resolves 20 pixels/mm; therefore, each pixel is ______ mm in size or _______ mm:
1/20; 0.05
A digital display device with higher megapixels has better _________:
spatial resolution
With digital radiography, problems with overexposure or inadequate brightness or contrast can be corrected during __________:
post-processing
In medical imaging, the ________ of spatial resolution is measured by the ________ of spatial frequency:
quality; quantity
If a line is 100 um, a line pair is 200 um; therefore, 1 lp/200 um=__________:
1 lp/0.2 mm, which equals 5 lp/mm
The use of two screens _________ the MTF because spatial resolution and spatial frequency are ________:
increases; decreased. Pixel size is not affected by screens.
A spatial resolution of 4 lp/mm resolves 8 objects per mm, each object being ___________:
1/8 mm or 0.125mm