Digital Imaging and Communications in Medicine (DICOM) is a standard that
governs this capability by specifying handling, storing, printing, and
transmitting information in medical imaging.

Grassroots DICOM (GDCM) is an implementation of the DICOM standard designed
to be open source so that researchers may access clinical data directly. GDCM
includes a file format definition and a network communications protocol, both
of which should be extended to provide a full set of tools for a researcher or
small medical imaging vendor to interface with an existing medical database.

GDCM is an open source implementation of the DICOM standard. It offers some
compatibility with ACR-NEMA 1.0 & 2.0 files (raw files). It is written in C++
and offers wrapping to the following target languages (via the use of swig):

Python, C#, Java, PHP (experimental), Perl (experimental).

It attempts to support all possible DICOM image encodings, namely:

RAW, JPEG lossy 8 & 12 bits (ITU-T T.81, ISO/IEC IS 10918-1), JPEG lossless
8-16 bits (ITU-T T.81, ISO/IEC IS 10918-1), JPEG 2000 reversible &
irreversible (ITU-T T.800, ISO/IEC IS 15444-1), RLE, Deflated (compression at
DICOM Dataset level), JPEG-LS (ITU-T T.87, ISO/IEC IS 14495-1).