MCQ on Computed radiography reader.

493.True regarding Computed radiography reader.

a.plate is removed from cassette in reader and scanned by laser

b.optical fibre above the plate  is used for scanning

c.rotating mirror above the plate direct emitted light to photomultiplier tubes

d.single scanning is enough to extract information

e.exposure of plate to light done to erase the residual signal



ANS OF PREVIOUS BLOG

473.True regarding mammography. 

a.aims to show microcacifications that may be 100micrometer or less

b.show tissues having much lower intrinsic contrast

c.atomic number of glandular tissues and adipose tissue (approx 7.4 and 6.5 respectively)

d.use of a broad bremsstrahlung spectrum  for imaging

e.target materials used for mammography  are tungsten ,molybdenum(z=42) and rhodium(z=45)

473.abc---- In mammography, use of a broad bremsstrahlung spectrum from a tungsten target is far from ideal and now it is standard practice to make use of the chararcteristic radiation from a lower atomic energy material giving rise to low energy X- rays (16-22 kev) .Target materials used for mammography  are  molybdenum (z=42) and rhodium (z=45),the former being most common. (Chapter 4,page no.74,second edition (2008),Farr’s Physics for Medical Imaging).