Single photon emission computed tomography (SPECT) imaging of dopamine D2 receptors in Parkinson's disease (PD): Relation to therapeutic response: G. Pizzolato, A. Rossato, M. Dam, F. Chierichetti ∗, C. Briani, G. Ferlin ∗, L. Battistin. Dpt of Neurology, University of Padova, Italy and ∗Nuclear Medicine, Hospital of Castelfranco Veneto TV, Italy