Chapter 2 Flashcards
(26 cards)
are currently available for the
acquisition of projection radiographs.
Digital systems
have been replacing
traditional analogue or screen–film (SF) systems
over the last three decades.
Digital radiography systems
The transition from an SF environment to a new
digital environment should be considered as a
complex process
Technical factors concerning _____________,
______________, and ____________ are some issues that could influence this
process.
image acquisition,
management of patient dose, diagnostic image
quality
In a transition process from SF to digital, patient
radiation doses could increase
40–103%
When compared to SF, digital technology could
increase patient radiation doses due to the _____________ they have.
wide
dynamic range
the dynamic range is useful because it
contributes for a __________ when
compared to traditional SF systems .
better clinical image quality
Digital imaging systems could facilitate over- or
underexposure that influences a
patient’s dose
Overexposure could provide good quality
images, but may cause
unnecessary patient dose
The first digital radiography system using the basic
principle of the conversion of the X-ray energy into
digital signals utilizing
scanning laser stimulated
luminescence (SLSL)
scanning laser stimulated
luminescence (SLSL) .
Was developed by __________ and
introduced in the market in the beginning of the
1980s
Fuji (Tokyo, Japan)
In the mid-1980s, the_____________ was developed
storage phosphor
systems
Today the Storage-phosphor radiography systems or
CR systems play a fundamental role in the field of
digital projection radiography
The high technical requirements and financial costs,
associated with limited image quality and difficult
handling—without a reduction of examination
time—delayed the transfer of storage phosphor
systems into routine clinical use, which started to
increase at the beginning of the
1990s
development of
flat-panel detectors in the middle of .
1995
_________ were initially developed to be
integrated detectors in the radiology equipment, but
more recently they are available as nonintegrated
detectors and working as a wireless or a
non-wireless technology.
Flat-panel detectors
Digital systems are traditionally split into two broadly
defined categories _________ and ________
computed radiography, digital
radiography
_______ that is used the Major difference among digital
technology systems related with X-ray detection and
readout process.
Taxonomy
CR systems use ____________ with a
separate image readout process, which means an indirect
conversion process.
storage-phosphor image plates
DR technology converts X-rays into electrical charges by
means of a direct readout process using _________
thin-film transistor
(TFT) arrays
Three components of digital detectors
- The capture element
- The coupling element
- charge readout element.
___________ can use either a direct or an indirect process for
converting X-rays into electric charges. These detectors use
direct-readout by means of a TFT array despite the
conversion process of the X-ray beam.
DR detectors
_________ have an X-ray
photoconductor—such as amorphous selenium (a-Se)—that
converts directly at only one stage X-ray photons into electric
charges.
Direct-conversion detectors
______ use a two-stage technique for
conversion:
They have a scintillator, such as cesium iodide (CsI) that
converts X-rays into visible light at a first stage. That light is
then converted—at a second stage—into an electric charge
by means of an amorphous silicon photodiode array
Indirect-conversion systems
