Fiji - Fiji: A batteries-included distribution of ImageJ.
Horos - A free, open source 64-bit DICOM medical image viewer
ImageJ - and Other Health Care
MicroDicom - DICOM viewer. MicroDicom is a free DICOM viewer. Export to the most common picture formats, movie, clipboard. It is equipped with most common tools for manipulation of DICOM images.
Athena DICOM Viewer - Athena DICOM Viewer is a breakthrough medical imaging software, an evolution of DICOM Viewers.
Icy - Icy is an open community platform for bioimage informatics