A 49 year old male presented with a two year history of progressively worsening akinetic rigid syndrome. After a number of non-specific findings on PET, MRI and CT scans of the brain, a clinical diagnosis was made of Parkinson’s disease, and treatment with Sinemet was commenced. The patient’s symptoms, however, were not sufficiently relieved and a change in medication was considered. However, after much persistence from the patient and his family in seeking a number of neurological opinions, a ¹²³I-metaiodobenzylguanidine (MIBG) cardiac study was requested to attempt to confirm the diagnosis of Parkinson’s disease. The patient’s medication was ceased for seven days prior to the study, and the patient was pre-treated with 10ml of potassium iodide one hour prior to ¹²³I-MIBG administration, to protect the thyroid. 185MBq of ¹²³I-MIBG was administered intravenously and planar and SPECT images of the chest were acquired at fifteen minutes and three hours post injection. A heart-to-mediastinum (H-to-M) ratio was calculated at both fifteen minutes and three hours post injection, to quantify the cardiac uptake of the tracer. The images demonstrated reduced uptake on the early images (H-to-M ratio of 0.75 [normal value – 1.52]) and further reduced uptake on the delayed images (H-to-M ratio of 0.68). This reduced cardiac uptake is associated with Parkinson’s disease, and provided sufficient evidence to confirm the initial clinical suspicion. As a result, the patient’s medication dosage is currently being reviewed, with more invasive therapies being considered.