The milligray/milliampere-seconds (mGy/mAs) measurement between adjacent mA stations should not vary by more than:

• A. 10%
• B. 1%
• C. 2%
• D. 5%

Answer: (A)

The idea is that beam output should stay consistent when you move to a nearby milliamperage setting at the same kVp, reflecting the generator’s linear response. For a fixed exposure time, changing the current from one mA value to the next should not change the resulting exposure (mGy) by more than about 10%; this keeps mGy/mAs fairly stable across adjacent settings. A 10% tolerance accommodates small inherent fluctuations in tube output, timer accuracy, and dosimeter measurement error while still catching meaningful nonlinearity or drift in the system. If the variation were tighter (like 1% or 2%), normal equipment variability would produce false flags; if it were set at 5%, some systems might still fail due to typical uncertainties, so 10% is the practical, commonly accepted standard.