THE DETECTION OF FOREIGN-BODIES IN SOFT-TISSUE - COMPARISON OF CONVENTIONAL AND DIGITAL RADIOGRAPHY

The vast majority of glass and metallic foreign bodies can be detected with conventional radiography. The visibility of common woods and pla stics is, however unknown. To assess their radiographic visibility, va rious woods and plastics of equal size were inserted into fresh porcin e tissue. The pork was then radiographed, under identical conditions, using conventional film-screen combination and a FUJI computed radiogr aphic system utilizing its edge-enhancement facility. The visibility o f the compounds was scored by four radiologists for both systems at va rious times post-insertion. Plastics were found to vary widely in visi bility. Dried timbers were visible initially but became isodense with time due to absorption of fluid from surrounding tissues. Fresh woods were invisible from the outset. The computed radiographs improved the visibility of objects visible with conventional radiography but did no t bring about visualization of those invisible to normal film-screen c ombinations. In conclusion the visibility of woods and plastics is var iable. Some improvement in visibility can be brought about by the use of digitally edge-enhanced computed radiographs.