Image intensifiers are utilised to convert low energy radiation into visible light images. Frequently the detector portion of an x-ray c-arm use in operating theatres, the image intensifier has a low scatter input portion comprised of low absorption substances such as titanium or aluminium 1,2.
Caesium iodide activated with sodium is the most commonly used input phosphor, the light produced by the phosphor of entry is converted via a photocathode to elections, these photoelectrons are then accelerated via a potential difference (photocathode to anode) toward the output.
The output portion of the image intensifier is most often comprised of silver-activated zinc-cadmium sulphide, converting the photoelectrons into light.
This process multiplies the number of photons resulting in an increase in brightness, a very useful tool in cases requiring long a duration of x-ray fluoroscopy 1.
The biggest advantage of an image intensifiers in medical imaging is the synergy of high detector efficiency and high conversion efficiency to effectively utilise fluoroscopy while adhering to the radiation protection principle of dose optimisation.