DCMTK is a collection of libraries and applications implementing large parts
of the DICOM standard. DCMTK includes software for examining, constructing and
converting DICOM image files, handling offline media, sending and receiving
images over a network connection, as well as demonstrative image storage and
worklist servers.  DCMTK comes in complete source code and is written in a
mixture of ANSI C and C++.

WWW: http://dicom.offis.de/dcmtk.php.en