Which technical factor does a technologist use to control receptor exposure?

The correct choice is milliamperage-seconds (mAs) because it directly influences the amount of radiation exposure that the receptor receives, which in turn affects the overall receptor exposure. The mAs represents the product of milliamperage (the current) and the duration of exposure in seconds. By adjusting the mAs, a technologist can control the quantity of x-rays that are emitted from the tube and how much of this radiation reaches the film or digital sensor, thus determining the brightness and quality of the resulting image.

While tube voltage (kVp) does play a significant role in image quality by influencing the penetration of the x-ray beam, it primarily affects contrast rather than direct receptor exposure. Similarly, the time of exposure (seconds) is a factor in mAs, but on its own does not provide the full picture of how receptor exposure is controlled. The distance from the source to the receptor contributes to the intensity of the radiation that strikes the receptor according to the inverse square law, but this is generally a fixed parameter for a given exam setup and is not typically adjusted during a single exposure.

Ultimately, mAs is the primary technical factor used to manipulate receptor exposure to achieve a well-exposed image.