Tuesday 29 July 2014

Frcr mcq --gamma camera (collimator)


11.True regarding collimators in gamma camera

a. placed in front of the crystal to restrict the direction of gamma rays entering the crystal

b. The usual form of collimator is a block of lead with an array of holes orientated perpendicular to the face of the crystal

c.The performance of the collimator is determined by the number of holes, the diameter and length of each hole and the septal thickness

d. the resolution of collimators designed for high-energy isotopes is generally poorer than that of those used for low-energy isotopes.

e. The pinhole collimator is a hollow metal cone that fits over a circular detector face, and has a single hole at its point.


ANS OF PREVIOUS BLOG


6.True regarding neutrino

a.released during beta decay
b.an extremely small mass
c.no charge
d.interacts extremely weekly with matter
e.no effect on patients

ANS --abcde-----

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