MRIcroGL
MRIcroGL is a cross-platform tool for viewing DICOM and NIfTI format images. It provides a drag-and-drop user interface as well as a scripting language. ([Rorden_2000]).
Official resources
References
[Rorden_2000]
Rorden C, Brett M. Stereotaxic display of brain lesions. Behav Neurol., 2000, 12(4):191-200.