Open Source Document Management System | OpenKM

DICOM feature was only available in professional version but anyway has been deprecated because was based on java applet support in browsers what has no longer exist.

Might be integrated in future alternatives - HTML5 DICOM - preview ( exist some ones ). If you want can work in the source code for it.

This might be a good starting point https://github.com/ivmartel/dwv

If you are going to work in our source code I suggest you download our development environment ( virtual machine ) what is the easies way to get the application running and apply changes. In our download section you have a video an the download link https://www.openkm.com/en/download.html