what is digital radiography?
The map of x ray transmission through patient is converted to a digital file
what determines the shade of the pixal in digital radiography?
x ray intensity
lots of radiation=black, not a lot of radiation= white, intermediate=grey
T/F A digital radiograph is composed of many small pixels, each with an assigned shade of gray
what format are the digital images converted to?
(digital imaging communications in medicine)
what does CR stand for?
image plate in cassette-like housing
what does DDR stand for?
direct digital radiography
flat panel detector
what does cassettes contain in CR?
imaging plate, not film!
cassettes must be processed in plate reader, images better than film
properties of DDR
no cassette to process
no plate reader
image available immediately
what are the 2 types of flat panel DDR?
indirect digital detector and direct digital detector
What type of flat panel DDR is represented here?
indirect: light intermediary
what type of flat panel DDR is represented here?
drect: no light intermediary
T/F direct is theorectically better but practically there is no detectable difference
properties of flat panel digital radiography (DR)
Immediately after exposure, image is viewable and ready to QC
Excellent quality image
Image plate is portable but subject to damage
what does the processing algorithm control?
T/F the image detail is better with digital radiograph
False it's contrast resolution
what are the advantages of digital
No darkroom, film, envelopes
Consultation – teleradiology
what is the exposure latitude
the extent to which a film, image plate or flat panel can be over or underexposed and still achieve an acceptable result.
T/F Exposure Latitude means that exposure factors are not important
under/overexposure is still a problem
what does a low exposure image have more of?
what happens when the plate overexposure passes its limit?
the plate becomes saturated and anatomy disappears
what has happened here
plate has been saturated, overexposure
what is contrast optimization
Application of additional processing ‘normalizes’ the image.
- Dark regions are made lighter and lighter regions darker
- = smooth ‘wide latitude’ radiograph
T/F exposure factors are lower with DR than with film-screen systems
proper exposure factors should be about the same
exposures can creep up-don't recognize its happening and can create safety concerns
what artifacts/technical problems can you still have with DR
poor radiation safety practices
wrong part radiographed
What is PACS?
Picture Archive and Communication System
Host of technologies that contribute to: Image creation, Image distribution/viewing, Image archiving