TFT, CCD, CMOS UPDATED ACTUAL
Exam Questions and CORRECT Answers
detector element - CORRECT ANSWER - del
AMFPI stands for: - CORRECT ANSWER - active matrix flat panel imager
2 major forms of xray conversion - CORRECT ANSWER - indirect and direct
direct conversion of xrays - CORRECT ANSWER - xray photons absorbed by coating
material and immediately converted into electrical signal
with direct conversion the flat panel detector has - CORRECT ANSWER - photoconductor
made of amorphous selenium
the amorphous selenium absorbs xrays and converts them to - CORRECT ANSWER -
electrons stored in the TFT detectors
TFT is a photosensitive array made up of small - CORRECT ANSWER - pixels
each pixel in a TFT has - CORRECT ANSWER - a photodiode that absorbs electrons and
creates electrical charge
more than _________ pixels can be read, converted to composite digital image in less than 1 sec
- CORRECT ANSWER - 1 million
_______________ or silicon TFT isolates each pixel element - CORRECT ANSWER -
field effect transistor
, A line of TFT switches, each associated with a ____________, allows the electrical charge
information to discharge when the switches are closed - CORRECT ANSWER - storage
capacitor
TFT stands for - CORRECT ANSWER - Thin Film Transistor
indirect conversion of xrays - CORRECT ANSWER - xray photons converted to light,
then light photons converted to electrical signal
phosphor layer is known as - CORRECT ANSWER - scintillation layer
what phosphors are commonly used for indirect conversion? - CORRECT ANSWER -
gadolinium oxysulfide or thallium doped cesium iodide
scintillation means - CORRECT ANSWER - giving off of light in a phosphor when struck
by xray photon
gadolinium oxysulfide is - CORRECT ANSWER - turbid unstructured phosphor, lower
spatial resolution
cesium iodide is a - CORRECT ANSWER - structured phosphor, increases spatial
resolution
unstructured phosphor layers produce - CORRECT ANSWER - more scattered light,
decreasing detector efficiency
each pixel contains a - CORRECT ANSWER - sensing component and switching
component
2 types of switching components - CORRECT ANSWER - two contact switching diode
and a three contact TFT
Exam Questions and CORRECT Answers
detector element - CORRECT ANSWER - del
AMFPI stands for: - CORRECT ANSWER - active matrix flat panel imager
2 major forms of xray conversion - CORRECT ANSWER - indirect and direct
direct conversion of xrays - CORRECT ANSWER - xray photons absorbed by coating
material and immediately converted into electrical signal
with direct conversion the flat panel detector has - CORRECT ANSWER - photoconductor
made of amorphous selenium
the amorphous selenium absorbs xrays and converts them to - CORRECT ANSWER -
electrons stored in the TFT detectors
TFT is a photosensitive array made up of small - CORRECT ANSWER - pixels
each pixel in a TFT has - CORRECT ANSWER - a photodiode that absorbs electrons and
creates electrical charge
more than _________ pixels can be read, converted to composite digital image in less than 1 sec
- CORRECT ANSWER - 1 million
_______________ or silicon TFT isolates each pixel element - CORRECT ANSWER -
field effect transistor
, A line of TFT switches, each associated with a ____________, allows the electrical charge
information to discharge when the switches are closed - CORRECT ANSWER - storage
capacitor
TFT stands for - CORRECT ANSWER - Thin Film Transistor
indirect conversion of xrays - CORRECT ANSWER - xray photons converted to light,
then light photons converted to electrical signal
phosphor layer is known as - CORRECT ANSWER - scintillation layer
what phosphors are commonly used for indirect conversion? - CORRECT ANSWER -
gadolinium oxysulfide or thallium doped cesium iodide
scintillation means - CORRECT ANSWER - giving off of light in a phosphor when struck
by xray photon
gadolinium oxysulfide is - CORRECT ANSWER - turbid unstructured phosphor, lower
spatial resolution
cesium iodide is a - CORRECT ANSWER - structured phosphor, increases spatial
resolution
unstructured phosphor layers produce - CORRECT ANSWER - more scattered light,
decreasing detector efficiency
each pixel contains a - CORRECT ANSWER - sensing component and switching
component
2 types of switching components - CORRECT ANSWER - two contact switching diode
and a three contact TFT
