Posteroanterior (PA) View

The posteroanterior (PA) view is the standard chest X-ray taken with the X-ray beam passing from the patient's back to the front, with the chest pressed against the detector and a full breath held. It gives the sharpest, least distorted picture of the lungs, and it is the view required for an ILO classification by a B-reader.

Origin

The PA view became standard practice in chest radiography because placing the chest close to the film, with the X-ray tube about six feet behind, reduces magnification of the heart and sharpens the lungs. The ILO guidelines for classifying dust-disease films are written for PA chest images.

Significance in Asbestos Context

Not every chest X-ray in a medical file is suitable for a B-read. Films taken in a hospital bed or emergency room are often anteroposterior (AP) views, with the beam passing front to back; they magnify the heart, may be taken without a full breath, and can hide or mimic changes in the lower lungs where asbestosis starts. A B-reader may grade such a film as unreadable or poor quality, or decline to classify it. That is why screenings for asbestos disease use a standing PA film taken at full inspiration, often with a side (lateral) view as well. For a trust or court claim, the quality grade the B-reader gives the film matters, and a poor-quality film can weaken the reading or require a new one. If the only films available are AP views from a hospital stay, a doctor may order a proper PA film, or a CT scan, to evaluate asbestos-related changes.

Example Sentence

The hospital's portable AP film could not be classified, so a standing PA view was taken at full inspiration and sent to a B-reader.

Related Terms

Chest X-Ray, B-Read, B-Reader, ILO Classification, Pleural Plaques, Asbestosis

Notes

• If you are asked to have a chest X-ray for an asbestos evaluation, it should be a standing PA view taken while you hold a deep breath.
• Bedside and emergency-room films are often AP views and may not be suitable for a B-read.
• Keep the image files, not just the written report; a B-reader needs to see the film itself.