The** “raw” data streaming from the CR reader requires shading corrections** to compensate for variations in the light-guide response for a uniform exposure to the plate (Seibert.2003). Over time, subtle deposits of material on the light guide produce fixed variations in light intensity. Adjustments to achieve uniformity are known as **“shading corrections” applied to the raw data during acquisition.
http://dev.medicalphysics.org/documents/Seibert1.pdf

Correction
Each projected image from the data set undergoes Geometric and **shading correction**, to remove spatial and intensity non-linearities introduced by the imaging device.
http://www.xtekxray.com/about/about_ct.html

Digital Imaging and Communications in Medicine (Imagen Digital y .... El término “raw data” se refiere a la información sin procesar y se ...... de imagen (por ejemplo, correcciones básicas del conjunto de datos de la imagen cruda..
http://www.icrp.org/docs/P93_Spanish.pdf