RADI 172 (Gary) - Final Exam From Quizzes
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100 Terms
___ is defined as the degree of geometric sharpness or accuracy of structural lines actually recorded in the image.
All of these are correct
3 multiple choice options
The ___ the matrix, the ___ the detail.
greater, greater
3 multiple choice options
(T/F) Unlike film-screen systems, there is no correlation between exposure level and spatial resolution.
True
The cassette-based system, in digital radiography uses a ___ imaging plate inside a cassette.
Photostimulable storage phosphor
3 multiple choice options
Direct acquisition digital radiography directly converts incoming x-rays into a(n) ___
electronic signal
3 multiple choice options
Indirect acquisition digital radiography uses a two-part process involving a scintillator and a photodetector. This system converts x-rays to ___ first.
Light
3 multiple choice options
A ___ converts incoming x-ray photons to light in an indirect system.
Scintillator
3 multiple choice options
The ____ is/are an indicator of potential "speed class" or is a measure of x-ray absorption efficiency.
DQE
3 multiple choice options
Higher DQE means that you have ___ patient dose.
lower
3 multiple choice options
As speed class or DQE decreases, the patient exposure increases while the likelihood of noise _____.
decreases
3 multiple choice options
characteristics affecting the spatial resolution for cassette-based systems include:
All of these
3 multiple choice options
___________refers to an image receptor's ability to respond to different exposure levels or the amount of error for optimal image acquisition.
Dynamic Range
3 multiple choice options
With digital imaging, an underexposure of 50% or greater results in a ____.
mottled image AND
image with noise
3 multiple choice options
The latent image loses about ___% of its energy in approximately 8 hours.
25%
3 multiple choice options
(T/F) With digital imaging, a radiograph does not have to adhere to the same rules of positioning as with film-screen systems. ( Histogram analysis and rescaling will fix it)
False
Misalignment may cause a ___ analysis error leading to incorrect exposure indicators.
Histogram
3 multiple choice options
(T/F) Digital radiography systems allows for much greater exposure range and have extremely low tolerance for patient overexposure.
False
A light guide Assembly:
All of these
3 multiple choice options
These are the two types of plate scanning mechanics:
Line scan and flying spot scan
3 multiple choice options
The DAP meter does the following 3 things EXCEPT
indicates the amount of exposure delivered to the image receptor
3 multiple choice options
Problems with Dose Area Product Meters include:
All of these are correct
3 multiple choice options
This replaces the visual cues of density and contrast that are used in analog imaging systems.
Exposure indicators
3 multiple choice options
Carestream uses an exposure index (EI) that is directly related to exposure and has a logarithmic component. Doubling the exposure would increase the (EI) by:
300
3 multiple choice options
This (vendor) brand of digital imaging system uses the logarithm of a histogram median or LogMean (LgM for their exposure indicators.
AgFa
3 multiple choice options
This/these vendor(s) utilize an S number for their exposure indicators.
Fuji & Phillips
3 multiple choice options
T/F: Inappropriate collimation or beam alignment can result in both histogram analysis error & rescaling error
True
Prior to image creation, the exposure values extracted from the PSP are subject to a process known as:
quantization
3 multiple choice options
_______ graphically represents a collection of exposure values extracted from the receptor.
histograms
3 multiple choice options
Each of the following are formats in which histograms can be analyzed EXCEPT:
photo histogram analysis
3 multiple choice options
With Priori Histogram Analysis, where does the standardized data set come from?
experiments of like subjects under ideal conditions
3 multiple choice options
Examples of histogram analysis errors:
incorrect anatomic menu selection, exposure field not detected, unexpected material in data set, inappropriate rescaling
The predetermined values used to create the image are known as:
the values of interest
3 multiple choice options
Imaging plates unused for more than _____ hours should be erased.
48
3 multiple choice options
What are some ways of reducing scatter?
beam limiting, use of optimal exposures, grid use, use of compression band
What is/are examples of beam-limiting device(s)?
All of these are correct
3 multiple choice options
_______ is one of the principle factors affecting the amount of scatter radiation produced?
kVp
3 multiple choice options
T/F: changes in kVp will not greatly affect radiographic contrast like it did with analog film-screen combos?
True
The Moire Effect may occur when:
All of these are correct
3 multiple choice options
the process of matching the captured image values to a standardized set of values is called:
automatic rescaling
3 multiple choice options
______ describes the concept of density as it is displayed on a soft-copy monitor.
brightness
3 multiple choice options
Increased _________ is considered one of the major advantages of digital receptors, and tends to counteract the lower spatial resolution of man digital imaging systems
contrast resolution
3 multiple choice options
smoothing is included under this type of digitized image filtering category:
low-pass filtering
3 multiple choice options
T/F: high-pass filtering either amplifies or deletes all but the high frequencies
true
T/F: Smoothing will NOT improve edge visibility
true
Low-pass filtering amplifies or deletes all but the ___ frequencies
low
3 multiple choice options
______ is a software function that reduces the appearance of noise in the image.
smoothing
3 multiple choice options
high-pass filtering also referred to as _________.
edge enhancement
3 multiple choice options
This type of artifact, associated with edge enhancement, can mimic a pathological condition & lead to improper diagnosis.
halo artifact
3 multiple choice options
________ is a software function designed to even out the brightness displayed in an image.
equalization
3 multiple choice options
excessive equalization can cause:
degradation of digital image
3 multiple choice options
________ is an indicator of the potential "speed class" or a measure of x-ray absorption efficiency.
DQE
3 multiple choice options
Ways at reducing scatter radiation include:
All of these reduce scatter
3 multiple choice options
T/F: digital radiography is mAs driven
false
T/F: there is no need to collimate with digital imaging systems
false
T/F: magnification no longer occurs with digital imaging systems meaning SID and OID no longer matter.
false
T/F: digital systems are more sensitive to fogging by scatter and/or background radiation than analog film-screen systems
true
T/F: fluorescent lights do not fog PSP plates.
true
T/F: automatic rescaling forces a technologist to look elsewhere for signs that a proper exposure was used to produce an image.
true
_______ refers to the potential to gradually increase patient dose over time.
dose creep
3 multiple choice options
What is the evaluation of digital images based on? *
image blur, exposure indicator, brightness, image noise
this replaces the visual cues of density and contrast that are normally used in analog imaging systems.
exposure indicator
3 multiple choice options
Overexposure greater than __________% results in a loss of image contrast
100-200%
3 multiple choice options
What four things are image brightness and contrast in a digital image affected by? *
1. exposure field recognition
2. grid cutoff
3. off focus radiation
4. wrong menu selection
Image _______ is the difference between adjacent densities
contrast
3 multiple choice options
this term describes the concept of contrast as it is displaced on a soft-copy monitor for digital images.
dynamic range
3 multiple choice options
Other terms used to describe spatial resolution include the following EXCEPT:
dynamic range
3 multiple choice options
What are the three types of motion found with digital imaging?
1. voluntary patient motion
2. involuntary patient motion
3. equipment motion
Blur can be caused by two things, motion and ______.
changes in geometric factors
3 multiple choice options
____________ is the misrepresentation of the size or shape of the structures being examined.
distortion
3 multiple choice options
T/F: with digital imaging, magnification is the only type of size distortion
false
T/F: Quantum noise in digital images is cause by insufficient signal strength.
True
T/F: factors affecting shape distortion include SID and/or OID
false
T/F: artifacts in digital imaging be grouped by image receptor type or by the origin of artifact
True
T/F: Processing artifacts, caused by a dirty light guide in the plate reader, can be best described in that the line (artifact) usually runs the entire length of the plate and is parallel to the direction the plate travels through the reader.
true
T/F: a DEL artifact can be fixed by replacing an individual DEL or row of DEL's
false
the three main types of acceptance testing include the following EXCEPT:
dark noise evaluation
3 multiple choice options
T/F: excessive dark noise degrades the digital image
true
With digital imaging and image brightness uniformity, a ______% variation in pixel value is allowed.
10%
3 multiple choice options
this test assesses exposure levels and the relative change in pixel density
linearity and slope
3 multiple choice options
T/F: the laser beam function test could be used to evaluate "jitter".
true
T/F: Noise and low contrast resolution can be evaluated utilizing the Leeds TO.12 phantom.
true
SMPTE is an acronym meaning this:
Society of Motion Picture and Television Engineers
3 multiple choice options
it is recommended that PSP plates be erased every __ hours if it has not been used
48
3 multiple choice options
T/F: to ensure consistency among image appearance, all systems within a facility should use identical processing codes
true
Types of monitors include all of the following EXCEPT:
DEL's
3 multiple choice options
this term refers to the number of pixels in a matrix and the size of the display screen.
spatial resolution
3 multiple choice options
CRT monitors typically have an aspect ratio of ___
4:3
3 multiple choice options
The _______ the bit depth, the _______ the range of color values that can be displayed
greater, greater
3 multiple choice options
the measurement from the center of one pixel to the center of the next is called:
pixel pitch
3 multiple choice options
regarding modality work list, HIS stands for this:
Hospital Information System
3 multiple choice options
T/F: PACS is a computer-based storage, retrieval and viewing system for digital imaging systems
true
PACS is an acronym that stands for:
Picture Archiving and Communication System
3 multiple choice options
this standard ensures adaptability between different imaging systems
DICOM
3 multiple choice options
another digital communication standard that sets rules for transmitting text-based patient information
HL7
3 multiple choice options
RAID is considered this type of storage device:
near-term
3 multiple choice options
this storage device is the largest device available
jukebox
3 multiple choice options
T/F: the jukebox is utilized as near-term storage
false
this process of remote transmission and viewing of images is called:
teleradiology
3 multiple choice options
Night hawking is a term used to refer to this:
off-site reading by radiologist not employed by the hospital
3 multiple choice options
When should the exported data from digital images be anonymized?
- if part of medical research
- if used for educational purposes