A collimator is an accessory to a SPECT/CT scanner. It can be compared to a camera lens or filter that enhances or improves photos. The prototype collimators are able to magnify target organs about four times compared to the current collimators. In this study we are validating a new collimator design, which will allow for quantitative measurement of dopamine receptors within the brain, not previously performed using a single photon gamma camera.

Previously PET/CT has been used for this measurement but the L-DOPA is not FDA approved and thus of limited availability. DatScan (I123 ioflupane) is an FDA approved and clinically indicated biomarker, which has a high binding affinity for presynaptic dopamine transporters (DAT) in the brains of mammals, in particular the striatal region of the brain. A feature of Parkinson's disease is a marked reduction in dopaminergic neurons in the striatal region. By introducing an agent that binds to the dopamine transporters a quantitative measure and spatial distribution of the transporters can be obtained. The use of SPECT/CT (with the new validated collimators) and the FDA approved DATScan biomarker would allow for readily available diagnosis of Parkinson's disease

Inclusion Criteria:

• all patients referred

Exclusion Criteria:

• anyone who wishes to not participate and cannot lay on the table for an additional 30 minutes.

Patients referred to Nuclear Medicine for a clinically indicated DatScan for the diagnosis of Parkinson's disease