The guidelines of the German Medical Association indicate
speed class SC 400 for PR of the knee joint. This concept,
based on standard film-screen systems, corresponds to dosage
indicator S in digital radiography. This is a device-specific
value which, under identical imaging conditions, correlates
with the image receptor dose. For images with reduced
dose, the dosage indicator was doubled, relying on similar
studies [8, 9], thus corresponding to an SC 800 sensitivity
class.