Digital Rad Flashcards
Types of direct receptors?
Indirect?
direct: CCD, CMOS, flat panel
indirect: photostimulable phosphors
wireless
CCDs use what?
charge coupled devices use silicon based semiconductors - break bonds between silicon
PSP plates good things
reusable, thin and flexible, no wires, used with existing x-ray equipment!
How to PSP plates work? How to use?
Europium with barium fluoride. x-ray energy is absorbed and stored, released when excited by another wavelength.
Take xray, scan with laser, erase, hygeine protection
how to erase PSP?
intense light for 2 minutes like a view screen
CCD/CMOS pros/cons
Pros: fast, high res
Cons: smaller, cable, expensive
PSP pros/cons
pros: film-like, no cable, large, cheap
cons: handling, lower res
Spatial resolution effected by what qualities in sensor?
Scatter of xrays within detector
thickness of phosphor
Does increase in radiation increase MAXIMUM spatial resolution?
NOOOO
Spatial res measured in terms of? minimum resolution?
line pairs per mm, at least 2 pixels required to resolve line pair
Greatest resolution?
CCD 25lp/mm
Film 20lp/mm
PSP 7lp/mm
detective quantum efficiency is?
What does a high DQE mean?
efficiency of detector in converting incident x-ray energy into an image signal
high DQE means less radiation needed for a good image quality
Can spatial resolution be influenced by product software?
no, is dependent on hardware only.
What CAN be improved by post processing?
contrast, artifacts, noise
Digital subtraction radiography can let you see
changes
