Parts a and b are reproduced from Valles, F. et al Parts a and b are reproduced from Valles, F. et al. Qualitative imaging of adeno-associated virus serotype 2–human aromatic L-amino acid decarboxylase gene therapy in a phase I study for the treatment of Parkinson disease. Neurosurgery 2010, 67(5): 1377–1385, by permission of Oxford University Press (REF.228). Parts c and d adapted with permission from Journal of Controlled Release, 240, Bankiewicz, et al. AAV viral vector delivery to the brain by shape-conforming MR-guided infusions, 434–442, Copyright (2016), with permission from Elsevier (REF.229).