Peg,
I go to Yale at the end of this month for my 4th SPECT scan (2003-2005-2007-2009) I hope one day this scan technique will be approved as a diagnostic tool for PD. They are also using this study to look for biomarkers for PD. (single photon emission computed tomography with BETA-CIT)
Here is an old medscape article about it.
Dec. 4, 2002 (Chicago) - A radiopharmaceutical-imaging agent - ioflupane (I123-FP-CIT) - used with single photon emission computed tomography (SPECT) is "98% accurate" for early diagnosis of Parkinson's disease, says David J. Tuite, MD, of Adelaide and Meath Hospital in Dublin, Ireland. Dr. Tuite presented findings here from a series of 50 patients who underwent SPECT screening using the radiopharmaceutical-imaging agent at the 88th Scientific Assembly and Annual Meeting of the Radiological Society of North America. medscape.com