Digital Imaging
The first full-scale PACS was installed in 1993 in
Baltimore
A look-up table maps
image gray scale values
Which of the following best describes the sequence for PSP image capture?
Phosphor plate, focused laser light scanner, photomuliplier, analog-digital converter, review station
The earliest CT of the head took several hours to acquire a single slice of information.
True or False
True
DICOM is a standard that allows imaging modalities and PACS to communicate in the same language.
True or False
True
Film and intensifying screens are primarily used in
conventional radiography
CR acquires an image through
the use of a storage phosphor plate
The invention of CT is heralded as
one of the greatest milestones in medical imaging
Teleradiography incorporated _____ to produce radiographic images.
telephone lines
When switching from a conventional diagnostic radiography room to one that incorporates CR major equipment changes are to be expected.
True or False
False
Early reconstruction of raw CT data took a few _____ to form a recognizable image.
days
Early picture archival and communication systems were first developed
by the U.S. military
Technologist efficiency ratings are generally the same when comparing conventional radiography with _____ radiography.
computed
Which modality was the first to use the principle of digital imaging?
Computed tomography (CT)
Indirect capture DR converts absorbed x-ray energy into visible light.
True or False
True
Storage phosphor plates are similar to
intensifying screens
The _____ converts x-ray energy directly to a digital electrical signal
photoconductor
Who was the first to incorporate digital imaging with the CT scanner
Godfrey Hounsfield
Exposure latitude is to conventional radiography as ____ is to DR.
dynamic range
The two elements needed to convert light signals into an electrical signal while using indirect capture DR are TFT and
photodiodes
Similar to CR, DR can use the existing diagnostic equipment found in today's imaging departments.
True or False
False
Present image annotation controls include all of the following except
date and time stamps
In which decades was MRI first introduced
1980s
A bucky apparatus is required for DR.
True or False
False
Storage phosphor plates are made with an active element of barium fluorohalide. What is the activator in the storage phosphor plate?
barium
Many PACS reading stations also have image-processing capabilities.
True or False
True
In a DR system, which of the following are needed to produce a radiographic image?
X-ray absorber and a CCD
In conventional radiography film processing, the sensitivity speck has which electrical charge?
Negative
One of the early goals related to the development of PACS was to
provide a means to move battlefield images to an established hospital
All of the following are components of a PACS except
independent kilovoltage peak and milliampere-second stations
Teleradiography, moving images via telephone lines to and from remote locations, was first conceptualized by
Albert Jutras
In reference to PSP iamge capture, to release the latent image, which of the following devices is scanned over the phosphor plate?
Focused laser light
With conventional radiography, optical density is primarily controlled by
milliampere-seconds
X-ray energy related to indirect capture DR will stimulate a ____, which eventually is changed into an electrical signal
scintillator
Intensifying screens
emit light
Which two modalities could easily be converted to digital image properties
Ultrasonography and nuclear medicine
The x-ray absorber typically used in direct capture DR is a
photoconductor
Compared with a 90-second processing time found in conventional radiography, image acquisition with DR has now been reduced to
3-5 seconds
Light exposing the film is in direct proportion to the amount and energy of the incident photon upon the screen.
True or False
True
The first commercial CT scanners could image the
head only
The ability of a digital system to display subtle changes in shades of gray is called
contrast resolution
If a pixel has a bit depth of 2 to the 9th, the number of gray tones that pixel can produce is
512
A system's ability to respond to varying levels of exposure, resulting in more detail, is referred to as
dynamic range
A perfect image processing system would have an MTF of
100%
How dark or light a digital image appears on a display monitor is known as
brightness
The size of the pixel is determined by the
matrix
"The sum of the components in a recording system cannot be greater than the system as a whole" is a definition of
modulation transfer function (MTF)
The efficiency of a system to convert x-ray input signal into a useful output image is known as
detective quantum efficiency
The more light spread, the ____ the MTF.
lower
The range of exposure values the image detector is able to produce is known as
latitude