(Reuters) – The U.S. Food and Drug Administration on Thursday approved drugmaker Eli Lilly and Co’s radioactive compound to detect tau, an important characteristic of Alzheimer’s disease.

Abnormal versions of two proteins, amyloid and tau, are involved in Alzheimer’s disease and considered hallmarks of the brain-wasting disease.

The FDA said Lilly’s compound, Tauvid, is the first drug that has gained the approval to detect tau tangles within the brain. This marks a leap from the current method of detection, which is to study the brains of people who have died.

Tau forms neurofibrillary tangles within neurons in the brains of people with Alzheimer’s disease.

Eli Lilly’s agent is given to patients intravenously and binds to certain sites in the brain where tau is known to form. The brain can then be imaged with a PET scan to identify these tangles.

Lilly’s compound is meant for the diagnosis and not treatment of Alzheimer’s, which is one of the top 10 leading causes of death in the United States.

(Reporting by Manas Mishra in Bengaluru; Editing by Amy Caren Daniel)