[Suitability and comparison of compensating filters for thoracic diagnosis]

The effect of three types of filter on the quality of radiographs of the chest was compared. These filters improve visualization of mediastinal structures without significantly reducing the quality of the pulmonary image. In practice the Du Pont filter proved best; the quality of the central and peripheral portions of the lung image is equal to that of an ordinary radiograph and visualization of the mediastinum is improved. The Agfa-Gevaert filter showed no significant disadvantages compared with the ordinary techniques but the improvement in mediastinal visualization is not that marked. The 3 M filter yields poor images of the central portions of the lung and its type of construction prevents the retrocardiac structures from being pictured as well as with the other filters.