What technical change is necessary to decrease receptor exposure when using automatic exposure control (AEC)?

To effectively decrease receptor exposure when using automatic exposure control (AEC), adjusting the density setting is crucial. The density setting allows the radiographer to modify the level of exposure relative to the automatic adjustments made by the AEC. By selecting a decreased density setting, the AEC system will reduce the amount of radiation it allows to reach the receptor. This results in less exposure, which can be particularly important in instances where you want to minimize radiation dose or if an image appears too dark (overexposed).

In contrast, options such as increasing milliamperage or decreasing kilovoltage peak would actually lead to increased receptor exposure. Higher mA increases the tube current, resulting in greater radiation output, while lower kVp generally makes the primary beam less penetrating, which could also inadvertently increase exposure if the AEC compensates by extending the exposure time.

Similarly, increasing the backup timer would not inherently decrease exposure; it only ensures that the system does not exceed a certain exposure duration, which might be necessary to prevent excessive radiation but does not directly control the exposure level during an AEC guided procedure.

Thus, adjusting the density setting downward is the most effective and direct means to manage and decrease receptor exposure in an AEC context.