Light therapy is a safe, easy way to kill cancer and treat other diseases, but it's normally limited by its nature to illnesses that are skin-deep. Washington University researchers aren't daunted, however. They've developed a phototherapy method that brings light directly to tumor cells, no matter how deep they are. The technique has you ingesting sugar combined with radioactive fluorine and light-sensitive, cancer-fighting nanoparticles. When you go through a PET scan, the sugar lights up and promptly kicks the nanoparticles into high gear. Effectively, this is a Trojan horse -- since tumors eagerly absorb sugar, they're sowing the seeds of their own demise.