What is the most likely outcome if the technologist decreases the kilovoltage peak (kVp) while using an automatic exposure control (AEC)?

When the kilovoltage peak (kVp) is decreased while using automatic exposure control (AEC), the system will respond to the reduced amount of x-ray photons penetrating the patient. AEC is designed to terminate the exposure once enough radiation has reached the receptor to produce an adequate image. Lowering the kVp means that fewer photons initially reach the receptor, which may not be enough to meet the predetermined exposure threshold set by the AEC.

As a result, the AEC system compensates for the decreased kVp by increasing the time the x-ray tube is activated, thus allowing the exposure to continue for a longer period to achieve the correct receptor exposure. This increase in exposure time ensures that the image quality remains acceptable despite the lower energy of the x-ray beam resulting from the decreased kVp.

Some other outcomes of adjusting kVp might also occur, such as changes in patient dose or image contrast, but the most direct effect in terms of AEC operation is the increase in exposure time to maintain adequate image quality.