Which technical change will increase the total exposure time without increasing the receptor exposure when using AEC?

When working with Automatic Exposure Control (AEC), the goal is to achieve optimal receptor exposure while minimizing unnecessary radiation. The correct choice of decreased milliamperage (mA) aligns with this goal because it allows for an increase in total exposure time without leading to an increase in receptor exposure.

When you decrease the milliamperage, the tube current is lessened, which in turn means the exposure time needed to achieve a sufficient dose for the desired image quality will need to be extended, since the output of x-rays per unit time is reduced. It requires a longer duration to deliver the same amount of exposure that would have been achieved at a higher mA setting. Importantly, because AEC systems are designed to terminate the exposure once the required receptor exposure is achieved, a lower mA with a longer duration results in maintaining the exposure level without increasing the receptor exposure.

In contrast, increasing kilovoltage peak (kVp), decreasing the backup timer, or increasing the density setting would generally lead to increased receptor exposure, which is not the intended result here. Increased kVp enhances the intensity and quality of the x-ray beam, which can increase receptor exposure. A decreased back-up timer can terminate the exposure sooner before adequate receptor exposure is achieved,