Ch 16 Digital Radiography Flashcards
screen-film requires _____
chemical processing
DR is more efficient in ________ than screen-film
time, ,space, and personnel
the capture element is that which:
captures the x-ray
the coupling element is that which:
transfers the x-ray generated signal to the collection element
the collection element may be:
a photodiode, a charge-coupled device CCD, or a thin-film transistor TFT
the photodiode collects ______
the CCD collects ____
the TFT collects _____
photodiode: light photons
CCD: light photons
TFT: electrons
SPR
scanned projection radiography
DRT
digital radiographic tomosynthesis
a CCD is a _____ sensing element, advantages are ______, it is a ________ semiconductor
light sensing, advantages are sensitivity, dynamic range, and size, silicon-based semiconductor
sensitivity of the CCD allows it to:
detect and respond to very low levels of visible light
dynamic range of the CCD allows it to:
respond to a wide range of light intensity, from very dim to very bright
CCD’s radiation response is ______
screen-film’s radiation response is _____
CCD: linear
screen-film: H&D curve response
CsI/CCD is an indirect DR process by which:
x-rays are converted first to light then to electric signal
CsI/a-Si is an indirect DR process by which:
x-rays are converted first to light and then to electric signal
fill factor:
the percentage of the pixel face that is sensitive to x-rays, approximately 80% (20% of the x-ray beam does not contribute to the image)
in DR as pixel size reduces, _______
spacial resolution increases but at the expense of the patient dose
spacial resolution in DR is:
pixel limited
in DR it is considered direct because:
there is no coupling element, the a-Se is both the capturing element and the coupling element
a-Se is a direct DR process by which _____ are converted to _____
x-rays are converted to electric signal
for soft tissue radiography ____ is more important than _____
contrast resolution is more important than spatial resolution
spatial resolution is limited to _____ and _____ is more important
pixel size in DR and contrast resolution is more important
CR uses ____ to generate a latent image; the visible image results when _______
PSP; the PSL is scanned with a laser beam
