New Test Can Help Diagnose Parkinson’s

The following article was written by Miguel Hernandez Pampaloni, M.D., Ph.D., an Assistant Professor in Residence and Chief of Nuclear Medicine in the Department of Radiology and Biomedical Imaging at UCSF.

A new test now offered at UCSF enables neurologists to more accurately diagnose Parkinson’s Disease in patients with essential tremor.  In combination with other tests and the clinical assessment of a patient’s particular symptoms, the DaTscan test is useful for differentiating among primary Parkinson’s Disease and all the diseases that exhibit the key symptom of Parkinson’s; namely, the essential tremor.

Concentrations of dopamine, a chemical released by nerve cells, are diminished in people with Parkinson’s.  In people with essential tremor caused by other diseases, dopamine concentrations are not diminished.  Therefore, identifying levels of dopamine can indicate whether an individual has Parkinson’s or not.

The DaTscan test looks at the area of the brain that controls motion and posture.  If the results of the test are positive, it means there is a lower amount of dopamine in that area, which is a strong signal that the patient has Parkinson’s.

During the DaTscan a small amount of Iodine 123 is injected into the patient’s bloodstream.  Iodine 123 is the radioactive isotope labeled to a small molecule that tracks the amount of dopamine in the brain.  After the injection, the patient lies on a table, and a gamma camera rotates around the patient for about 30 minutes.  The gamma camera records the distribution of radiation emitted from the Iodine 123.

The test is painless, but it requires several hours between the intravenous injection and the actual imaging.  As soon as the test is completed, the patient may resume normal activities.  Results are obtained the same day as the test, and a report is sent immediately to the neurologist.

The DaTscan test has been used for the last 12 years in Europe, where it has been administered to approximately 300,000 patients with no significant side effects or reports of any major adverse events.  Iodine 123 is a well-known isotope used for other clinical applications, which is easy to administer and which yields reliable data. In addition, the amount of radiation that the patient is exposed to with this test is minimal.

The test was approved for use in the United States two years ago.  It is covered by the
Centers for Medicare & Medicaid Services (CMS), as well as by most private insurance companies.

In summary, the DaTscan test can be very valuable for patients with essential tremor.  For more information about the DaTscan test or other nuclear medicine services offered at the UCSF Department of Radiology and Biomedical Image, please contact us here.

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