What it means
A DaTscan shows the nerve endings that release dopamine, a chemical messenger that helps control movement. A tracer called ioflupane is injected and attaches to the dopamine transporter (the DaT in the name) on these nerve endings. They sit in a deep brain area called the striatum. On a normal scan, each side looks like a bright comma. When these nerve cells are lost, uptake drops, usually first at the back, and the shape shrinks toward a dot.
When it matters
A reduced scan supports a loss of dopamine nerve cells. This happens in Parkinson's disease and in related conditions such as multiple system atrophy, progressive supranuclear palsy and dementia with Lewy bodies. The scan cannot tell these apart. A normal scan makes them unlikely and points toward other causes, such as essential tremor or medicine side effects. The diagnosis is made by a neurologist, who weighs the scan with your symptoms and examination.
Questions to ask your doctor
- Is the reduced uptake on one side or both, and how marked is it?
- Could any of my medicines have affected the result?
- How does this result fit with my symptoms and examination?
Read more: DaTscan for Parkinson's: What the Result Means and What It Cannot Say
