Procedures - Chapter 1, Part E - Digital Imaging
Radiographic contrast in the digital image is primarily affected by: A) kV B) signal to noise ration C) application of processing algorithms D) matrix size
C
The current range of spatial resolution for digital radiographic imaging systems is between: A) 1.0 - 2.0 lp/mm B) 10 - 50 lp/mm C) 0.5 - 1.0 lp/mm D) 2.5 - 5.0 lp/mm
D
___ is the application of specific image processing that alters the pixel values across the image so as to present a more uniform image appearance.
Equalization
What three factors affect distortion in digital imaging?
SID, OID, CR alignment
Which of the two pixel sizes is most critical in maintaining high resolution digital images?
acquisition
List the terms describing the two pixel sizes used in digital imaging.
acquisition pixel size, display pixel size
Digital processing involves the systematic application of highly complex mathematical formulas called ___.
algorithms
Highly complex mathematical formulas used in creating the digital image are termed:
algorithms
Post-processing that adds text to images.
annotation
which one of the following factors will result in an increase in noise? A) excessive mAs B) scatter radiation C) high kV D) decrease in pixel size
b
In digital imaging, the term ___ replaces density as applied in analog-based imaging.
brightness
In post-processing, window level controls the ___ of the digital image
brightness
The intensity of light that represents the individual pixels in the image on the monitor is termed:
brightness
List the six image quality factors to evaluate digital images.
brightness, contrast resolution, spatial resolution, distortion, exposure indicator, noise
In post-processing, window width controls the ___ of the digital image
contrast
The difference in brightness between light and dark areas of an image is known as ___.
contrast
A digital imaging system's ability to distinguish between similar tissues is ___.
contrast resolution
The greater the bit depth of a digital system, the greater the:
contrast resolution
The range or level of image contrast in the digital image is primarily controlled by ___.
digital processing
In addition to acquisition pixel size, spatial resolution in the digital image is controlled by ___.
display matrix
What is the minimum pixel size that can be displayed by a monitor?
display pixel size
The misrepresentation of object size or shape as projected onto radiographic recording media is ___.
distortion
Exposure latitude is also known as ___.
dynamic range
Post-processing that increases brightness along the margins of structure to increase visibility of the edges.
edge enhancement
A numeric value that is representative of the exposure the digital image receptor receives is termed the ___.
exposure indicator
Dynamic range is also known as ___.
exposure latitude
T/F: Brightness cannot be altered in the digital image once it has been processed.
false
T/F: Changes in kV have little impact on patient dose with digital imaging
false
T/F: Digital imaging requires that images be chemically processed.
false
T/F: Digital imaging systems have a narrow dynamic range
false
T/F: Focal spot size has no impact on the resolution of the digital images?
false
T/F: OID and SID have little impact on spatial resolution of the digital image.
false
T/F: The factors that affect image distortion for the digital image are different from those that affect film-screen systems.
false
T/F: a high SNR results when an insufficient mAs is used in creating a digital image.
false
T/F: postprocessing can correct for a low SNR image
false
The smaller the acquisition pixel size, the ___ (lesser/greater) the spatial resolution.
greater
A ___ (high/low) SNR is desirable in digital imaging.
high
Post-processing that reverses the light and dark pixel values of an image.
image reversal
Verifying the exposure indicator for each exposure is essential in producing quality digital images with the ___.
least possible dose to the patient
What does lp/mm mean?
line pairs per millimeter
When insufficient mAs is applied in the production of a digital image, it produces a ___ (high or low) SNR image
low
What causes a low SNR?
low mAs
What is the primary factor for SNR?
mAs
List the four factors that affect the exposure indicator in the digital image.
mAs, kV, total IR area irradiated, objects exposed
Post-processing that enlarges all or part of an image.
magnification
Each digital image is two-dimensional and is formed by a ___ of picture elements called pixels.
matrix
Another term for image noise is ___.
mottle
A random disturbance that obscures or reduces clarity is ___.
noise
The ___ of the image depends on the display capabilities of the monitor.
perceived resolution
Each digital image is formed by two-dimensional elements termed:
pixels
Changing or enhancing the electronic image to improve its diagnostic quality is called ___.
post-processing
The primary controlling factor of contrast in the digital image is:
processing algorithms
SNR is the acronym for ___.
signal to noise ratio
Post-processing that applies specific image processing to reduce the display of noise in an image.
smoothing
A radiographic image that is viewed on a computer monitor is known as a ___.
soft copy
The recorded sharpness or detail of structures on the image is known as ___.
spatial resolution
Post-processing that removes background anatomy to allow visualization of contrast media-filled structures.
subtraction
T/F: A wide exposure latitude associated with digital imaging systems will reduce repeat exposures.
true
T/F: Changes in mAs do not have a primary controlling effect on digital image brightness.
true
T/F: Digital images are a numeric representation of the x-ray intensities that are transmitted through the patient.
true
T/F: kV and mAs do not have the same direct effect on image quality with digital imaging as they do with IR-screen imaging.
true
T/F: the current range of spatial resolution for digital general radiographic imaging is between 2.5 - 5 line pairs per MM.
true
Exposure latitude with digital imaging is more ___ (narrow/wide) when compared with analog imaging.
wide
