Sunday, 10 August 2014

FRCR MCQ -----FILTRATION


6.True regarding filtration
a.responsible for low energy cut-off  of the x ray spectrum
b.K-edge filter has k-edge in lower energy part (ex.-erbium)
 c.K-edge filter remove only high –energy  X –rays
d.K-edge filter is relatively transparent to the energies just above  the K-edge
e.K-edge filter is routinely used 

Ans of previous blog

19.True regarding computed radiography
a.photostimulable phosphor have norrow dynamic range
b.there is a linear relationship between signal from a computed radiography plate and dose to the plate
c.the latitude of the CR system is very much greater than for conventional radiography
d.choice of gradation curve are dependent on the projection
e.histogram analysis involves an analysis of the distribution of the light intensities outside  the collimated area

19.bce----Photostimulable phosphor have a wide  dynamic range,being able to record photon intensities varying by a factor of about 10000:1.To display useful image ,the processing of the data from the reader involves  to detect the collimated edges of the X-ray beam ,histogram analysis and optimization of gradation curve . Histogram analysis involves an analysis of the distribution of the light intensities within  the collimated area. .(Chapter 5, page no.84-85,second edition (2008),Farr’s Physics for Medical Imaging).

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