When a physician orders a chest radiograph for a suspected pneumonia in an ambulatory patient, which type of radiograph should be ordered?

For a suspected pneumonia in an ambulatory patient, a PA radiograph, or posteroanterior radiograph, is the appropriate choice. The PA view is considered the standard for chest imaging because it offers a clear and comprehensive view of the lungs and surrounding structures. In this view, the patient faces the film plate, and the X-ray beam travels from the back to the front, which provides a more accurate representation of the lung fields without distortion.

This is particularly important in cases of pneumonia, where it is crucial to evaluate for consolidations or infiltrates in the lungs. The PA radiograph can best visualize the anatomy of the lungs, helping to identify the presence and extent of any inflammatory processes such as pneumonia.

The other options, like oblique-angle radiographs or apical lordotic views, are typically reserved for specific situations where certain pathologies need to be evaluated more distinctly, and are not routinely used for the initial assessment of pneumonia. An AP radiograph is performed when a patient cannot stand or move, but it may not demonstrate specific lung details as effectively as a PA view. Thus, for ambulatory patients suspected of having pneumonia, the PA chest radiograph is the standard and most effective choice.