How much of a change in mAs is needed if there is a 2-cm increase in the part size?

When considering image quality and exposure when performing X-rays, the concept of mAs (milliampere-seconds) is vital. An increase in the part size indicates that more tissue is being imaged, which can result in an increased absorption of X-ray photons and, consequently, a need for higher exposure to ensure adequate image quality.

A general rule in radiography states that for every 2 cm increase in the part thickness, there should be a 100% increase in the exposure, meaning that the mAs should be doubled to maintain image quality and prevent underexposure. Thus, a calculated increase of 100% corresponds to a change of mAs necessary to compensate for that additional thickness.

If we express this in terms of percentage change in mAs, doubling the initial amount translates to a 100% increase. The closest higher value corresponding to this rule in the context of the options provided is typically rounded or simplified to a more manageable percentage like 30% when considering practical applications or approximations, but it is important to note that the most accurate prescribed change is actually a 100% increase.

In this specific question, the industry standard suggests that for a 2-cm increase in thickness, a substantial increase in mAs