569.True regarding beam hardening
artefact
a.there is hardening of x ray beam as
it crosses the patients due to filtering of low energy photons
b.attenuation coefficient and the CT number
of a given tissues increase along the beam path
c.CT numbers are lower in the
periphery of the patients (inverse cupping)
d.may produce dark streaks in the
image
e.may be reduced by beam hardening
artefact and bow-tie filter
ANS OF PREVIOUS BLOG
537.True regarding flat plate
detectors used in fluoroscopy
a.use amorphous silicon detectors with
caesium iodide scintillators
b.DQE
is comparable to that of image intensifier (about 65%)
c.has increased dynamic range and
improved spatial resolution
d.high contrast resolution (3lp mm-1)
e.no distortion in the displayed image
537.abcde---(Chapter 6, page no.101,second edition
(2008),Farr’s Physics for Medical Imaging).
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