MEDRADSC 2Y03 Study Guide - Final Guide: Edge Enhancement, Spatial Frequency, Radiodensity
28 Jul 2019
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Increase thickness = increase scatter (depends on the anatomy) Wider collimation = increased chance for rays to scatter. Minimize scatter, image has less noise (bc more signal), more contrast (black & white, no gray) Positive beam limitation = collimation that starts w ir size; automatically adjusts. If pbl starts with an initial size, always want to collimate in smaller. Made of lead strips w a radiolucent material in b/n. What is the 1st body part is upper extremity that needs a grid = humerus. Gr = height of lead strips/distance b/n them. Higher the gr = less scatter to the ir. Prior to feeding the cr cassette into the cr reader, the echnologist must select the algorithm or roi. Algorithms are applied to determine the useful image data range of the x-ray exposure imprinted on the imaging plate. When the x-ray beam exposes the psp, the energy transfer results in excitation of the electrons into a metastable state.
