The FDA has approved Eli Lilly’s Tauvid (flortaucipir F18) to help detect Alzheimer’s disease in adults with cognitive impairment.

The radioactive compound is for use in positron emission tomography (PET) imaging of the brain to estimate the density and distribution of tau neurofibrillary tangles, a primary marker of the disease.

The approval marks a significant advance for Alzheimer’s research. Previously, the disease could only be confirmed by brain analysis after patients died.