The double contrast barium enema: improvements to lateral decubitus views including the use of a wedge filter.
The prognostic importance of early detection of colonic carcinoma is emphasised and the contribution of an accurate barium enema technique is stressed. Horizontal beam lateral decubitus films are routine in double contrast barium enemas, and it is still common practice in many departments to support the cassette for these views either in the bucky tray or with sandbags. The lateral decubitus views of 100 patients using these methods of cassette support were reviewed. A large number of the films (67%) were technically so unsatisfactory due to unilateral under- or over-penetration that they did not provide acceptable visualisation of the colon. The cause of these technical faults, and the methods by which they may be overcome, are described. In addition, a wedge filter was designed to reduce the absorption by dependent soft tissues in obese patients.