Which change will not cut the receptor exposure in half when using 300 mA, 40 ms exposure, and 85 kV?

The reason 10 mAs is the change that will not cut the receptor exposure in half lies in the relationship between milliamperage, exposure time, and the resulting mAs (milliampere-seconds) used for imaging.

In this scenario, the original setup uses 300 mA and an exposure time of 40 ms, resulting in an exposure of 12 mAs (300 mA x 0.040 s = 12 mAs). To halve the receptor exposure, you would generally need to halve the mAs value, which would lead to a target of 6 mAs.

When looking at the other options, adjusting to 1/50 sec exposure time will change the mAs significantly but will likely lead to a reduction that could cut the receptor exposure in half. Lowering the kV to 72 would also decrease the receptor exposure—since lower kilovoltage reduces the amount of x-ray photons produced. Changing to 150 mA while keeping the same exposure time of 40 ms would also effectively halve the mAs because 150 mA x 0.040 s equals 6 mAs.

However, setting the exposure to 10 mAs (by adjusting mA or time) does