There may be alternatives to spending tens of thousands of dollars for imaging software. Lance Ladic's web page lists a number of freeware tools that may be worth considering (http://www.cs.ubc.ca/spider/ladic/conflink.html). One that I've had experience with is VolVis--free, powerful, and runs on either SGI's or Sun's. I think you now get it by sending an e-mail note to [log in to unmask] There are also other software packages that are cheaper than VoxelView, e.g. VoxBlast, and Image Volumes (...The latter is a brazen plug, since Image Volumes is written by a friend).