How is milliampere-seconds (mAs) calculated in an exposure using 70 kVp, 300 mA, and 0.1 s?

To calculate milliampere-seconds (mAs) during a radiographic exposure, you use the formula:

mAs = mA × time (in seconds)

In this scenario, you have a milliampere (mA) value of 300 and a time duration of 0.1 seconds. By substituting these values into the formula:

mAs = 300 mA × 0.1 s

This results in:

mAs = 30 mAs

This calculation demonstrates how mAs is directly proportional to both the milliampere setting and the exposure time. The higher the mA or the longer the exposure time, the greater the mAs, which ultimately affects the quantity of radiation produced and the overall image quality. Understanding this relationship is crucial for radiographic practice, as it allows for adjustments to be made to optimize image quality while also adhering to safety protocols regarding radiation exposure.