RT Journal Article SR Electronic T1 Upregulation of Putaminal Dopamine D2 Receptors in Early Parkinson's Disease: A Comparative PET Study with [11C]Raclopride and [11C]N-Methylspiperone JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 65 OP 70 VO 41 IS 1 A1 Valtteri Kaasinen A1 Hanna M. Ruottinen A1 Kjell NĂ¥gren A1 Pertti Lehikoinen A1 Vesa Oikonen A1 Juha O. Rinne YR 2000 UL http://jnm.snmjournals.org/content/41/1/65.abstract AB