What does the milliampere-seconds (mAs) control in radiography?

The milliampere-seconds (mAs) is a critical measurement in radiography that directly influences the quantity of radiation produced during an imaging procedure. Specifically, mAs is a product of the tube current (measured in milliamperes) and the time (in seconds) that the x-ray tube is energized.

Increasing the mAs leads to a greater number of photons being generated during the exposure, which results in a higher dose of radiation reaching the image receptor. This increase in radiation quantity enhances the overall density of the radiographic image, making it more visible, but it does not alter the quality or energy levels of the radiation itself.

The quality of radiation is primarily controlled by kVp (kilovolt peak), which affects the penetrating power of the x-rays rather than their quantity. Adjustments in exposure time are related to mAs but do not capture the essence of what mAs specifically defines.

Thus, mAs is fundamentally responsible for controlling how much radiation is produced, impacting the exposure received by the patient and the resulting diagnostic image.