title: Age-related decline in dopamine transporter in human brain using PET with a new radioligand [¹⁸F]FE-PE2I.
abstract: OBJECTIVE
  Dopamine transporter (DAT) density is considered as a marker of pre-synaptic function. Numerous neuroimaging studies have consistently demonstrated an age-related decrease in DAT density in normal human brain. However, the precise degree of the regional decline is not yet clear. The purpose of this study was to evaluate the effect of the normal aging process on DAT densities in human-specific brain regions including the substantia nigra and thalamus using positron emission tomography (PET) with [(18)F]FE-PE2I, a new PET radioligand with high affinity and selectivity for DAT.
  
  
  METHODS
  Thirty-six healthy volunteers ranging in age from 22 to 80 years were scanned with PET employing [(18)F]FE-PE2I for measuring DAT densities. Region of interest (ROI)-based analysis was used, and ROIs were manually defined for the caudate, putamen, substantia nigra, thalamus, and cerebellar cortex. DAT binding was quantified using a simplified reference tissue model, and the cerebellum was used as reference region. Estimations of binding potential in the caudate, putamen, substantia nigra, and thalamus were individually regressed according to age using simple regression analysis. Estimates of DAT loss per decade were obtained using the values from the regression slopes.
  
  
  RESULTS
  There were 7.6, 7.7, and 3.4% per-decade declines in DAT in the caudate, putamen, and substantia nigra, respectively. By contrast, there was no age-related decline of DAT in the thalamus.
  
  
  CONCLUSIONS
  [(18)F]FE-PE2I allowed reliable quantification of DAT, not only in the caudate and putamen but also in the substantia nigra. From the results, we demonstrated the age-related decline in the caudate and putamen as reported in previous studies, and additionally for those in the substantia nigra for the first time.
authors.affiliation: Department of Neuropsychiatry, Nippon Medical School, Sendagi 1-1-5, Bunkyo-ku, Tokyo, 113-8602, Japan.
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Shingai
authors.forename: Amane
authors.initials: A
authors.lastname: Tateno
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Arakawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sakayori
authors.forename: WooChan
authors.initials: W
authors.lastname: Kim
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Okubo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009662:Nortropanes; D049268:Positron-Emission Tomography / Q000379:methods*; D013045:Species Specificity; D055815:Young Adult
chemical_list: C543996:(E)-N-(3-iodoprop-2-enyl)-2beta-carbofluoroethoxy-3beta-(4'-methyl-phenyl) nortropane; D050483:Dopamine Plasma Membrane Transport Proteins; D009662:Nortropanes