Computed tomography (CT) theoretically improved detection of foreign bodies and provided more information of adjacent soft
tissues. The CT scanner and picture archiving and communications system (PACS) program proved to be an excellent instrument
for detection and localization of most soft tissue foreign bodies above certain minimum levels of detectability. The characters of
metal and non-metal material in penetrating trauma to the soft tissue, it is often underestimated by physical examination. So, diagnosis
of a retained foreign object is always critical and difficult. From March 2007 to February 2009 a study was done with 100 patients
who had soft tissue trauma. Axial and coronal CT images were obtained with a CT scanner (HiSpeed Advantage CT/i). And
then, we measured CT Hounsfield units (HU) of foreign body to remain in the soft tissue. The metallic foreign bodies consisted of
stainless steel (2,222±737 HU), titanium (2,921±218 HU), gold (2,908±325 HU), lead (2,758±539 HU), copper (2,909±228 HU), silver
(3,069 HU) and mean value is 2,633±603 HU. Non-metallic foreign bodies consisted of silicone (278±120 HU), glass (947±523
HU), polyethylene (32±5 HU), polylactide plate (144±16 HU), stone (1,320±280 HU), plastic (-47 HU), wood (-464 HU) and mean
value is 557±526 HU. The PACS program allows one to distinguish metallic from nonmetallic foreign bodies and to individually
identify the specific composition of many nonmetallic foreign bodies. This program does not, however, allow identification of the
specific composition of a metallic foreign body.