A Dopamine Transporter (DAT) scan is a specialized imaging test that provides insights into the brain’s dopamine system. This procedure helps healthcare providers evaluate certain neurological conditions by visualizing specific brain activity. The following explains the steps involved in undergoing a DAT scan, from preparation to receiving results.
What a DAT Scan Does
A DAT scan uses a nuclear medicine imaging technique to visualize dopamine transporters in the brain. These proteins on nerve cells manage dopamine, a chemical involved in controlling movement. The scan focuses on the striatum, a brain region affected by conditions that impact dopamine-producing neurons. By assessing transporter activity, the scan can help differentiate between various movement disorders.
The procedure is commonly used to distinguish essential tremor from Parkinsonian syndromes, including Parkinson’s disease. In conditions like Parkinson’s disease, the scan can detect a reduction in dopamine transporter activity. This imaging tool serves as an adjunct to other clinical evaluations, providing objective information about the dopamine system’s integrity.
Preparing for Your Scan
Preparation for a DAT scan involves several important steps. Discuss all current medications with your doctor, as certain drugs can interfere with the scan’s findings. Some medications, particularly those affecting dopamine levels, may need to be temporarily stopped for a specific period before the scan. Follow precise instructions from your healthcare provider regarding medication adjustments.
A crucial part of the preparation involves taking an iodine compound, either in pill or liquid form, at least one hour before the radioactive tracer injection. This iodine helps protect the thyroid gland from absorbing the radioactive material. Patients are encouraged to drink plenty of fluids before and after the scan to help eliminate the tracer from the body. Wearing comfortable, loose-fitting clothing is also recommended.
The Scan Process
The DAT scan begins with the administration of a radioactive tracer, typically iodine-123 ioflupane, into a vein in the arm. This tracer binds specifically to dopamine transporters in the brain. After injection, a waiting period of three to six hours allows the tracer to travel through the bloodstream and accumulate in the brain, binding to dopamine transporters in the striatum.
During this waiting period, patients may be able to leave the facility or remain in a comfortable waiting area. Once the tracer has adequately distributed, the imaging phase begins. The patient lies still on a table, which then moves into a Single Photon Emission Computed Tomography (SPECT) scanner. The camera rotates slowly around the head to capture detailed images of the brain.
The scan itself typically lasts between 30 and 45 minutes. Remaining as still as possible is important to ensure clear images. A flexible head restraint may be used to minimize head movement. The scanner comes close to the head but does not touch the patient.
What Happens After the Scan
After the imaging is complete, patients can typically resume their normal activities. There are usually no significant restrictions following the scan. Patients are advised to continue drinking plenty of fluids for a day or two to help eliminate the remaining radioactive tracer. Any mild side effects, such as headache, nausea, or dry mouth, are generally temporary and resolve on their own.
The images from the DAT scan are analyzed by a specialist, such as a nuclear medicine physician or radiologist, who then prepares a report. This report is sent to the doctor who ordered the scan, usually a neurologist. The time it takes to receive the results can vary, typically ranging from a few days to a couple of weeks. The interpreting physician will discuss the scan findings in conjunction with other clinical information.