Hi @chrissymc - welcome to Mayo Clinic Connect.
We are not doctors and don't have medical training, but perhaps some of the members in the Parkinson's disease support group can share what they've learned from their own experiences with their doctors and their reading and research.

Here's some Mayo Clinic information on PD diagnosis, including a description of DAT scans:

Parkinson's disease: Diagnosis https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/diagnosis-treatment/drc-20376062.

You may also find this Connect discussion specifically on DAT scans useful:

- DAT scan for Parkinsons disease usefulness and cost https://connect.mayoclinic.org/discussion/dat-scan-for-parkinsons-disease-usefulness-and-cost/

Have you been experiencing symptoms that led your doctor to order this scan? If so, will you share more about what symptoms you've had?