Meanwhile, flux gain is the number of photons generated at the output phosphor, comparing with photons generated at input phosphor 5.īrightness gain from minification does not improve the statistical quality of the image because same number of photons is reaching output phosphor whether the input screen is larger or smaller. It makes the image brighter but does not improve the quality and contrast of the image. Minification gain is the ratio of the input area to output area of phosphor. Brightness gain is the product of minification gain and flux gain (also known as electron gain). The output of the image intensifier can be evaluated by brightness gain and conversion factor. The electrons hit the output phosphor and cause large numbers of light photons to be produced, which subsequently may be captured by various imaging devices 3,4. Focussing and distortion minimization is accomplished by the focussing electrodes 5. The electrons are accelerated towards the output fluorescent screen by an electric field produced between the photocathode and anode. ![]() ![]() The light photons strike the photocathode of the input screen and are absorbed by photoelectric interactions, causing it to emit photoelectrons (via the photoelectric effect) 5. After the x-ray beam emerges from the patient, it enters the image intensifier tube through the input window typically made of low scatter low absorption substances such as titanium or aluminum 1,2 The x-ray beam is then partially absorbed by the fluorescent input screen ( entrance phosphor) creating a number of light photons 5.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |