Imaging foreign bodies.

Radiologic technologists are likely to image a wide variety of foreign bodies in the course of their careers and should know which techniques work best in different circumstances. This article reviews the strengths and limitations of radiography, ultrasonography, computed tomography, and magnetic resonance imaging for visualizing foreign bodies and describes the imaging appearance of some common foreign-body materials, including glass, metal, wood, plastic, stone, and rubber. Several special types of foreign bodies also are discussed, such as medical devices, concealed packets of illegal drugs, and self-embedded items. The intraoperative role of imaging during removal of foreign bodies also is described.