MEDRADSC 2F03 Lecture Notes - Lecture 14: Europium, Latent Image, Digital Imaging
15 Dec 2016
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Document Summary
By identifying the image data range through algorithms allows efficient and accurate digitization. Important for maintaining the subtle contrast signal differences of the anatomic structures. Applied to determine the useful image data range of the x-ray exposure imprinted on the detector. Typically by using histogram analysis techniques to identify the max and min signals. Made of an infinite number of points of relative blackening. Each point resembles one location in x-ray field. Each point could have any quantity of blackening between dmin (b+f) and dmax (highest possible od on film) Ea(cid:272)h poi(cid:374)t"s (cid:271)la(cid:272)ke(cid:374)i(cid:374)g (cid:396)ep(cid:396)ese(cid:374)ts (cid:395)ua(cid:374)tity of (cid:396)adiatio(cid:374) t(cid:396)a(cid:374)s(cid:373)itted th(cid:396)ough the path at that location. Remnant beam photons are absorbed by phosphor crystals. X-ray energy excites electrons from valence band into the trap centers (f-center) Electrons can reamin in trap centers (high energy states) for a few days, slow fading over time. Small quantity of europium (increases efficiency of trapping electrons)
