Researchers in Japan have developed a new brain scan which could help doctors accurately diagnose Alzheimer's.
The scan allows doctors to detect a protein called tau which builds up in the brains of Alzheimer's sufferers.
There is currently no fail-safe method to test for the degenerative illness which effects around 500,000 people in Britain.
Until now, it has only been possible to confirm a diagnosis of Alzheimer's by looking at the brain after a person's death, according to Alzheimer's Research UK.
Dr Eric Karran, director of research at Alzheimer's Research UK, heralded the discovery as "promising" but warned "more long-term studies" were needed to see how much the scan could be used to track the progression of the disease.