According to a study by Australian researchers, it takes about 20 years for beta amyloid deposits, biomarkers for Alzheimer's, to lead to full-fledged dementia, meaning that if build-ups can be identified early through brain scans, physicians have a sizable window for treating the disease. This could be good news for the likes of GE Healthcare ($GE) and Navidea Biopharmaceuticals ($NAVB), which are both developing imaging agents designed to ferret out beta amyloid in the brain, but, to date, drug developers have struggled mightily to craft treatments that can reverse the disease's progress. Report