'A' Level Medical Option Questions - X-Rays
Q3.
![](dIAGRAM3.png)
The diagram shows a fluoroscopic image intensifier.
(a) State the purpose of:
(i) the fluorescent screen, A,
It converts X rays to visible photons ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(ii) the photocathode,
It converts photons to emission of electrons ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(iii) the anodes,
They increases the kinetic energy of electrons travelling from cathode to anode
and they also focus the rays of electrons to produce a faithful image ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(iv) the fluorescent screen, B.
It converts (increased) electron energy into light photons ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(4 marks)
(b) Give one example of a medical application for which an image intensifier might be used. Explain why the use of an image intensifier is required.
It might be used for a dynamic process - such as fluid flow
It cuts the radiation dose whilst still providing good image [or allows multiple or continuous use of X rays] ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(2 marks)
(Total 6 marks)