How much should the central ray be angled cephalad for an AP axial projection of the chest if the patient cannot assume the lordotic position?

For an AP axial projection of the chest when the patient cannot assume the lordotic position, the central ray should be angled cephalad to effectively project the clavicles above the apices of the lungs. The standard angle recommended is 15 degrees cephalad. This angle is sufficient to minimize superimposition of the clavicles over the lung fields and to provide a clear visualization of the lung apices.

When using this angle, the positioning is critical because it helps maintain the anatomical structures of interest properly aligned for optimal imaging. A 15-degree angle effectively compensates for the patient's position, allowing radiologists to obtain a view that closely resembles what would be seen in a true lordotic position while still ensuring diagnostic quality.