Reduction of patient doses from barium meal and barium enema examinations through changes in equipment factors.

A study of patient doses for barium meal and barium enema examinations has been made for X-ray departments throughout Grampian Region. Dose-area products are substantially less than UK reference levels. Contributions from fluoroscopy and radiography varied significantly between different units, with fluoroscopy making up 35-92% of the mean doses for barium meals and 24-57% for barium enemas. Equipment related factors had a greater influence on patient doses than radiologists' techniques. The gain of the image intensifier and the exposure factors selected by the automatic exposure control (AEC) were the most important factors determining doses for fluoroscopy. Changes in kV/mA factors selected by the AEC have allowed reductions of 20-50% to be made in effective dose from fluoroscopy with some units. The method used for recording images was the major influence on radiographic doses. Digital spot images or fluorographic films taken from the intensifier gave only 10-20% of the dose with a film/screen system and are recommended where the image quality is satisfactory for the application. Changes in film/screen systems have given worthwhile reductions in radiographic doses. If all factors are optimized, mean doses for barium examinations could be reduced to 20% of current reference levels.