Question

Regarding image quality in fluoroscopy: 

a. The signal-to-noise ratio (SNR) will improve by increasing the image intensification or camera gain 

b. The veiling glare is only from the light scattering in the output window and is not affected by scattering of the X-rays in the input screen 

c. Veiling glare means a blurry line surrounding the image 

d. Vignetting means the periphery of the image is brighter than the centre 

e. The larger the intensifier, the greater the veiling effect

Answer 1

a. False. For an image intensifier, quantum sink corresponds to the photons absorbed in the input screen. Increasing the image intensifier or camera gain will not improve the SNR. 

b. False. Veiling glare is mainly from light scattering in the output window but also by X rays and light scattering in the input phosphor and electron scattering in the tube itself. 

c. False. It means dark regions in the image appearing lighter because of the surrounding light areas. 

d. False. It means that the central area of the image is brighter than the periphery.

e. True.