Final answer:
If an AEC cell is not correctly adjusted and all chambers are left on during a lateral chest x-ray, the result will be an overexposed image due to the system shortening the exposure time unnecessarily.
Step-by-step explanation:
If the AEC cell was not correctly changed after doing a PA chest x-ray and all the chambers were left on for the lateral view, the lateral will appear overexposed. The Automatic Exposure Control (AEC) is designed to automatically adjust the exposure to the optimal level for the part of the body being imaged. When a chest x-ray is performed, usually only the center cell is used for a lateral view. If all chambers are left on, the AEC system will detect the additional radiation passing through the less dense areas around the patient, causing it to shorten the exposure time. This will result in more radiation than necessary reaching the image receptor, thereby producing an overexposed image, where the finer details of the tissues will likely be obscured due to the excessive brightness.