MCQ ON INTENSIFYING SCREEN

450.True regarding intensifying screen.

a.lanthanum oxybromide ,activated with  terbium ,emits a line spectrum of red light

b. lanthanum oxybromide ,activated with  terbium can be used with ordinary X-ray

c.Gadolinium and lanthanum oxysulphide activated with terbium emit yollow light

d. Gadolinium and lanthanum oxysulphide activated with terbium can be used with an orthochromatic film

e.red safe light is necessary in orthochromatic film while amber safe light is used with ordinary x ray film

ANS OF PREVOUS BLOG

436.True regarding heel effect

a.less intensity of x rays towards the cathode edge

b.steeper the target, the greater is the heel effect

c.reduced heel effect for a given film size at longer FFD

d.roughening increases the heel effect

e.place the thicker part of patients towards cathode side

436.bcd----Due to heel effect ,there is less intensity of x rays towards the anode edge  and so thicker part must be placed on cathode side. Heel effect is gradual,so not noticeable on even largest film. ---(Chapter 3,page no.62,second edition (2008),Farr’s Physics for Medical Imaging).