This ppt includes about computed radiography i.e., CR with exposure process and layers of imaging plating and explaination about every layer consists of imaging plates also contains PSP Image acquisition and processing, Detection and Conversion of the PSL Signal, advantages and disadvantages about CR and Recent advances in computed radiographic (CR) detector and readout technology.

1. Cassette Digital
radiography
(COMPUTED RADIOGRAPHY)
Presenter - Bhavana Katiyar
PRN - 19040121027
Course – Fundamental of Medical Image
Processing
Programme – B.Sc. Medical Technology
Specialization - Imaging Science

2. Computed radiology (CR) also commonly known as Photostimulable
phosphor(PSP) imaging, employs reusable imaging plates and associated
hardware and software to acquire and to display digital projection
radiographs.
CR systems make use of image plates having a detective layer of
photostimulable crystals that contain different halogenides such as
bromide, chlorine, or iodine (e.g., BaFBr:Eu2).
It involves the PSP plate detector handling between two sequential stages
of exposure and data acquisition.
Image plate in cassette must be processed in CR reader X-ray exposure for
conversion to digital images in raster pattern.
COMPUTED RADIOGRAPHY

3. The exposure
process with
storage-
phosphor
image plates

4. LAYERS OF IMAGE PLATING
PROTECTIVE LAYER
BARIUM FLUR HALIDE PHOSPHOR LAYER
LIGHT REFLECTIVE LAYER
CONDUCTIVE LAYER
POLYSTER SUPPORT LAYER
LIGHT SHIELDING LAYER
BACKING LAYER

5. Protective
layer
A thin layer of
transparent
film that
protects the
phosphor.
Backing
Layer
This is a
protective
layer made
from a soft
polymer that
prevents
scratching
when the
plates are
stacked
during the
manufacturing
process.
Barium Fluor
halide Phosphor
Layer
A closely
dispersed of
fine-grained,
Photostimulable
europium-
activated,
barium Fluor
halide crystals,
that store the
latent image
until released
when re-
stimulated
during
processing.
Light reflective
Layer
This layer
increases the
intensity of
light being
emitted from
the crystals by
reflecting it
back toward
the reader,
instead of it
being
absorbed
Conductive
Layer
This is a light
absorbing
layer, made up
of conductive
needle-like
crystals that
absorb any
unreflected
light as well as
any
electrostatic
charges.
Polyester
Support Layer
Made from a
polyester
material, this
layer gives
structural rigidity
and a base for
the coating of all
of the other
layers. Polyester
is used because
of its excellent
stabilities well as
its durability and
flexibility.
Light
Shielding
Layer
This is a
carbon particle
layer that
prevents the
light from
leaking from
the rear of the
imaging plate.

6. PSP Image
acquisition
and
processing

7. Detection and Conversion of the PSL Signal

8. a. Imaging plates are reusable
b. No darkroom or chemicals needed
c. Reduction in exposure and processing time
d. Software-based evaluation and reporting
e. Simple digital information exchange and archiving
ADVANTAGES
DISADVANTAGE
a. Manual handling of the cassette housing.
b. Imaging plates are expensive and can be easily damaged.
c. Inherent geometric lack of sharpness results in lower spatial resolution, as
compared to film images.
d. Low signal-to-noise ratio and sensitivity to scattered radiation.

9. Recent
advancements
Recent advances in computed radiographic (CR) detector and readout
technology have been the
1. Introduction of dual-side readout methods,
2. Structured PSP detectors,
3. Parallel readout methods
• Recent innovations in CR, including the use of dual-sided image readout
and channelled storage phosphor have eased these concerns.
• For example, introduction of these technologies has improved detective
quantum efficiency (DQE) by approximately 50 and 100%, respectively,
compared with standard CR.
• As a result CR currently affords greater scope for reducing patient dose,
and provides a more substantive challenge to the new solid-state, flat-panel,
digital radiography detectors.

10. THANK
YOU