Elevated [18F]FDOPA utilization in the periaqueductal gray and medial nucleus accumbens of patients with early Parkinson's disease. - Yoshitaka Kumakura; Erik H. Danielsen; Albert Gjedde; Ingo Vernaleken; Hans-Georg Buchholz; Andreas Heinz; Gerhard Gründer; Peter Bartenstein; Paul Cumming (NeuroImage, 2010)