Molecular imaging of AChE is of interest to help clarify the role of the enzyme in Alzheimer disease progression, in particular.34,38 Imaging of AChE has been well studied and an interested reader should consult one of the excellent reviews on recent progress in radionuclide-based molecular imaging for AChE.38, -40 Since publication of those reviews, several more articles on PET imaging of AChE have appeared.41, , , , , -47. The gene discussed is ACHE; the disease is Alzheimer disease.