Wednesday, 9 July 2014

MCQ ON Beam hardening artefact


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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