Transcript IMAGE RECEPTORS - Montgomery College

IMAGE RECEPTORS
Follow the Sequence- Film System






Tube
Patient
(bucky) or non-bucky
Cassette
INTENSIFYING SCREEN
FILM
Follow the Sequence- Filmless (CR)
System







Tube
Patient
(bucky) or non-bucky
Cassette
IMAGING PLATE
DIGITIZER OR READER
MONITOR
Follow the Sequence- Filmless (DR)
System





Tube
Patient
(bucky) or non-bucky
DIGITAL RECEPTOR
MONITOR
INTENSIFYING SCREEN



PG 179
When using intensifying screens in cassette the
exposure to the film is 90% -99% FROM
LIGHT
Anatomy of a screen




Protective layer
Phosphor or active layer
Reflecting or absorbing layer
base
PHOSPHORS




SPECTRAL EMISSION
RARE EARTH
HIGH ABSORPTION +HIGH
CONVERSION EFFICIENCY=
FASTER SPEED
PHOSPHOR THICKNESS, SIZE









Impacts screen speed and detail
Faster screen =less detail = less mAs
Slower screen = more detail =more mAs
Old screen speed/new screen speed
Reflecting layers = increase screen speed
Light absorbing layer or light absorbing
dyes=decrease speed but increase recorded detail
Table 7-9
Quantum Mottle
Screen Maintenance
Follow the Sequence- Filmless (CR)
System







Tube
Patient
(bucky) or non-bucky
Cassette
IMAGING PLATE
DIGITIZER OR READER
MONITOR
CR cassette





Protective layer
Photostimulable phosphor
Reflective layer
Base
Backing
Barium Fluorohalide crystals coated
with europium







Phosphor releases some visible light
The x-ray energy is absorbed (trapped)
Latent image
Sensitive to a wide range of energies
Erase plate if not used in 48 hours
Process within an hour of exposure
Increase mAs as CR is equivalent to 200 screen speed
vs 400 screen speed used in film systems…why?
Follow the Sequence- Filmless (DR)
System





Tube
Patient
(bucky) or non-bucky
DIGITAL RECEPTOR
MONITOR
DIRECT CAPTURE DETECTOR
TFT –Thin film transistors –flat panel consists of
detectors and TFT’s
 Radiation interacts with the detector (within the table,
upright chest unit or on a extremity unit)
 X-rays are either converted to light that reacts to a
layer of amorphous silver = electric chargeCCD
(CHARGE COUPLED DEVICE)
Or
 X-rays are interact directly with layer of amorphous
silver = electric charge
