Line spread function
Q.True regarding line spread function graphs is/are.
a. relative density increases with distance away from slit
line
b. microdensitometer is needed to read micro variation in density over large area
c. the less the light diffusion ,the sharper will be image
d. the image will be sharper with slower screen rather
than fast screen
e. the LSF of x ray film exposed without screens is more
easy to measure
ANS====cd----In
line spread function graphs relative density decreases with distance away from
slit line source of x ray.The photographic effect of the x-ray beam is spread
over a total distance of 800 or more micron while width of slit is 10
microns.
Microdensitometer is needed to measure film density over such small area
,say 800microns .
The LSF of x ray film exposed without screens is difficult to
measure because there is almost no diffusion of x rays and secondary electrons
in the film,so the LSF is narrow.
[Chapter 14,Page 209, 4th edition ,1990 reprinted 2010 , Christensen’s Physics of
Diagnostic radiology].
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