CAMRT Radiography Practice Exam

If the AEC is positioned over the petrous ridges for a skull x-ray, how will the rest of the image appear?

1. Underexposed

2. Overexposed

3. Crisp and clear

4. Neutral

The correct answer is: Overexposed

When the AEC (Automatic Exposure Control) is positioned over the petrous ridges during a skull x-ray, the remaining anatomy often does not adequately trigger the AEC to stop exposure. The petrous ridges are dense bony structures that can absorb a significant amount of radiation. Consequently, the AEC will continue to be activated until the radiation reaching it surpasses its predetermined threshold, typically leading to an extended exposure time. As a result of this prolonged exposure, the other parts of the skull and surrounding tissues that are less dense will be exposed to more radiation than necessary. This excessive radiation can result in an image that appears overexposed, characterized by a loss of detail, brightness, and contrast. Therefore, positioning the AEC over the petrous ridges can lead to an overall image that is overly bright and lacks clarity in less dense areas.