What is the minimum change in mAs needed to show a perceptible difference on the image?

The minimum change in milliampere-seconds (mAs) required to produce a perceptible difference in image density is generally accepted to be around 30%. This threshold is important in radiography, as it ensures that technicians can make appropriate adjustments to the exposure settings when necessary. When mAs is increased or decreased by at least this amount, it leads to a noticeable change in the brightness and contrast of the image captured, making it easier to differentiate between structures or abnormalities within the radiograph.

An adjustment of less than 30% may not yield sufficient contrast or a visible change for the radiologist to assess properly, which may impact diagnostic accuracy. Thus, understanding this principle helps radiologic technologists make informed decisions about exposure alterations while maintaining optimal imaging standards.