Change: http://www.med.umich.edu/opm/newspage/2005/hmtrojan.htmTiny particles one-billionth of a meter in size can be loaded with high concentrations of drugs designed to kill brain cancer. What's more, these nanoparticles can be used to image and track tumors as well as destroy them, according to researchers at the University of Michigan Comprehensive Cancer Center.   View changes from previous version. (Word count: 572)

Change: "Photofrin goes into tumor blood vessels and collapses the vasculature, which then starves the tumor of the blood flow needed to survive. The problem with   View changes from previous version. (Word count: 561)