Transcript Digital Imaging - Montgomery College

Digital Imaging
acronyms
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PSP
CRT
ADC
IP
CR
DR
PACS
SNR
CNR
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CCD
11. FOV
12. LUT
13. DICOM
14. RIS
15. HIS
16. TFT
17. DQE
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Photostimulable phosphor-europian activated
barium fluorohalide (=200 speed)
Cathode-ray tube or computer monitor
Analog to digital converter
Imaging plate
computed
/digital radiography
Picture archiving communication systems
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SIGNAL TO NOISE RATIO PG 410 –BUSHONG The higher the signal the
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CONTRAST TO NOISE RATIO can be manipulated until noise
less the noise.
becomes too apparent-limited by the SNR
10. Charge coupled device- crystal silicon- small, replaces vidicon in
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fluoro, device used in DR
Field of View –how much of the patient is imaged in the matrix
Look up Table – plotting grays on a scale
Digital imaging and communications in medicine -blending PACS
and other imaging modalities
Radiology Information system
Hospital Information system
16. Thin Film Transmitters-
indirect conversion
detector in DR. Stores electronic charge (from converted light)
before computer processes it.
17. Detective Quantum Efficiency converting x-ray
intensities into a radiographic image
18. DAP-Dose Area Product-multiplication of the dose and the
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area exposed
NYQUIST-Sampling frequency of digital data
• Computers connected together in a
hospital by LAN
• Outside computers connected to
hospital server by VPN
INDIRECT LAYERING
• FLUORESCENT (ONLY IN
INDIRECT-WHY?)
• PHOTODETECTOR LAYER
• TFT
• AMORPHOUS SILICON-RELEASES
ELECTRONS WHEN STRUCK BY
LITE (INDIRECT)
• AMORPHOUS SELENIUMRELEASES ELECTRONS WHEN
STRUCK BY X-RAY PHOTONS
(DIRECT)
FOV/MATRIX/PIXEL
• FOV can increase without change to
Matrix or Matrix can change w/o
change to FOV –
• What about the pixel?
Question?
• Does the pixel size change if the
FOV changes and the matrix stays
the same? Or what if the matrix
changes but the FOV stays the
same?
• If the FOV increases and the matrix
stays the same, the pixel size
increases