What Is a DaT scan?
A DaT scan, or dopamine transporter scan, gives a visual map of your brain’s dopamine system. Dopamine is very important for controlling movement, and in people with Parkinson’s, cells that produce dopamine slowly die off. The DaT scan helps to show if these cells are working properly by highlighting areas in the brain that have less dopamine activity. In simple terms, the scan helps doctors see if the part of your brain that controls movement is affected. This test is not a cure or a treatment, but it does provide useful information to help further confirm a clinical diagnosis.
Getting a DaT Scan: The Process
A DaT scan is arranged by your doctor, usually after they have noticed some signs or symptoms that might point to Parkinson’s. If your GP is unsure about your diagnosis, they might refer you to a neurologist. Your neurologist can then decide whether a DaT scan would be helpful to provide extra evidence. The process starts with an injection of a very small dose of a safe radioactive substance, often called ioflupane. This substance travels to the part of your brain that uses dopamine (i.e. dopamine transporters), which are found in an area called the striatum.
After the injection, you will wait for a few hours to allow the substance to spread evenly through your brain. Then, a special camera called a SPECT scanner (single-photon emission computed tomography) takes detailed pictures of that area. The pictures show the amount and distribution of dopamine transporters in the brain. Areas where there is less dopamine activity appear darker in the images. This helps doctors spot if the dopamine-producing cells, especially in a region called the substantia nigra, are not working as they normally would. The whole process is non-invasive and generally takes about one day. Although the procedure involves radioactive material, the dose is very low and is considered safe.
Interpreting the results
It is very important to understand that a DaT scan is just one part of the overall diagnosis of Parkinson’s. While a scan can show lower levels of dopamine transporters in people with Parkinson’s, not every person with Parkinson’s will have a scan that perfectly matches their symptoms. In fact, around 85% of patients with typical Parkinson’s symptoms show abnormal DaT scan results, which helps support the diagnosis (Marek et al., 2000; Politis, Pavese, & Piccini, 2010). However, there is a small group of patients—often referred to as having “scans without evidence of dopaminergic deficit” (SWEDD)—who have normal DaT scan results but may still be monitored over time. Studies suggest that only about 5%–10% of those initially suspected of having Parkinson’s receive normal DaT scans and go on to be diagnosed later with the condition (Lees, Hardy, & Revesz, 2009).
Sometimes, a normal DaT scan helps doctors rule out Parkinson’s and point towards another condition, such as essential tremor. This shows how useful the DaT scan can be when doctors are faced with uncertain symptoms. In Australia, the use of DaT scans has grown by roughly 30% over the past five years as more specialists appreciate the extra clarity it provides. It is also worth noting that these scans have a diagnostic sensitivity of around 85% and a specificity of roughly 80%, meaning they are quite reliable in differentiating Parkinson’s from other movement disorders.
What else should you know?
If you need a DaT scan, your doctor will guide you through the process. The test is not routine for everyone with Parkinson’s symptoms—it is used in specific cases where the clinical picture is not clear enough. If you receive a normal DaT scan result, it does not immediately rule out Parkinson’s. In some cases, especially in the early stages of the disease, the dopamine system might not have changed enough to show up on the scan. This is why doctors often combine the results of the DaT scan with a careful review of your symptoms and medical history, and sometimes may repeat the scan later if needed.
Beyond diagnosis, DaT scans can help doctors plan a better treatment approach by confirming the loss of dopamine-producing cells. As research continues and technology improves, the accuracy and usefulness of DaT scans are likely to get even better. This is a positive sign for the future of Parkinson’s management, ensuring patients receive the most appropriate care as early as possible.
The future and your health
While a DaT scan does not treat Parkinson’s, it is a useful part of the diagnosis process. By confirming changes in the brain’s dopamine system, doctors can start treatment earlier and work to slow down the symptoms. Ongoing research is constantly making DaT scans better and more precise. This progress gives hope to many people as it leads to improved treatment plans and a better understanding of the condition. It is a reminder that advancements in technology and research are working together to help those with Parkinson’s live a good quality of life.
Living well with good information
Understanding how these scans work, and what their results mean, can help you feel more in control of your health. If you or a loved one is undergoing a DaT scan, remember that it is simply one of the many tools doctors use to ensure the best care. We are here to support you with trusted advice, and we encourage you to discuss any questions with your care team. Remember, every step towards understanding your condition is a step towards better living.
References
Lees, A. J., Hardy, J., & Revesz, T. (2009). Parkinson’s disease. The Lancet, 373 (9680), 2055–2066.
Marek, K., Innis, R. B., & Seibyl, J. (2000). The role of DaT scan imaging in Parkinson’s disease research. Journal of Nuclear Medicine, 41(8), 1235–1240.
Parkinson’s Australia. (n.d.). Statistics and facts. Retrieved from https://www.parkinsons.org.au/statistics/
Politis, M., Pavese, N., & Piccini, P. (2010). The use of DaT scans in the diagnosis of Parkinson’s disease. Brain, 133(5), 1453–1464.
