CAMRT Radiography Practice Exam

Which ionization chamber(s) should be activated when using AEC for an AP pelvis projection?

1. Center chamber only

2. Center, and upper right and left chambers

3. Upper left chamber only

4. Upper right and left chambers

The correct answer is: Center, and upper right and left chambers

When utilizing Automatic Exposure Control (AEC) for an anteroposterior (AP) pelvis projection, it is essential to activate the center chamber along with both the upper right and left chambers. The pelvis is a broad anatomical structure, and activating only the center chamber may not adequately account for variations in tissue density throughout the entire area being imaged. By employing all three chambers—center, upper right, and upper left—a more uniform exposure is achieved, ensuring that the image captures the entirety of the pelvis with appropriate radiographic density. The additional chambers help in compensating for differences in thickness and density of the surrounding tissues, leading to a more accurate representation of the anatomy and preventing potential underexposure or overexposure that could occur with activating just one chamber. This approach optimizes the functioning of the AEC system, contributing to improved image quality, which is crucial for diagnostic accuracy in radiographic examinations of the pelvis.