Use of a metal detector to identify ingested metallic foreign bodies

A metal detector reveals the presence of metallic objects by measuring the change in the inductance of a coil placed near a metallic mass. The device used in this study is similar in principle to those used for passenger surveillance in airports except for its smaller size and simpler design. In this study, we compared the accuracy of a metal detector with that of plain radiographs for the localization of ingested metallic objects. Twenty-eight consecutive patients with the presumptive diagnosis of metallic foreign-body ingestion were examined with a metal detector. The results were compared with those of plain radiographs which were considered the gold standard. Fifteen positive cases and 13 negative cases were correctly diagnosed by metal detector examination. No false-positive or false-negative results occurred. Our experience suggests that metal detection is a simple and accurate technique for the localization of ingested metallic objects and provides information equivalent to that from plain radiographs for the treatment of patients with suspected foreign-body ingestion.