There is a Sample Data module included with Slicer. There is a notice that the “CTA Abdomen (Panoramix)” is only for research and teaching purposes and not for comercial purposes. Can anyone elaborate on the status of the other datasets?
The panoramix is from the osirix samples, and yes, those are restricted.
Unless otherwise noted the other Slicer SampleData should be available according to the data contribution sections of the Slicer License which lets you do pretty much anything with them. For sure the MRHead is under the Slicer License.