@article{oai:repo.qst.go.jp:00045098,
 author = {Fujita, Masahiro and Fujimura, Yota and Suhara, Tetsuya and et.al and 藤村 洋太 and 須原 哲也},
 issue = {1},
 journal = {NeuroImage},
 month = {Mar},
 note = {The peripheral benzodiazepine receptor (PBR) is upregulated on
activated microglia and macrophages and thereby is a useful biomarker
of inflammation. We developed a novel PET radioligand, [11C]PBR28,
that was able to image and quantify PBRs in healthy monkeys and in a
rat model of stroke. The objective of this study was to evaluate the ability
of [11C]PBR28 to quantify PBRs in brain of healthy human subjects.
Twelve subjects had PET scans of 120 to 180 min duration as well as
serial sampling of arterial plasma to measure the concentration of
unchanged parent radioligand. One- and two-tissue compartmental
analyses were performed. To obtain stable estimates of distribution
volume, which is a summation of Bmax/KD and nondisplaceable activity,
90 min of brain imaging was required. Distribution volumes in human
were only ~5% of those in monkey. This comparatively low amount of
receptor binding required a two-rather than a one-compartment model,
suggesting that nonspecific binding was a sizeable percentage compared
to specific binding. The time-activity curves in two of the twelve subjects
appeared as if they had no PBR binding—i.e., rapid peak of uptake and
fast washout from brain. The cause(s) of these unusual findings are
unknown, but both subjects were also found to lack binding to PBRs in
peripheral organs such as lung and kidney. In conclusion, with the
exception of those subjects who appeared to have no PBR binding, [11C]
PBR28 is a promising ligand to quantify PBRs and localize inflammation associated with increased densities of PBRs.},
 pages = {43--52},
 title = {Kinetic Analysis in Healthy Humans of a Novel Positron Emission Tomography Radioligand to Image the Peripheral Benzodiazepine Receptor, a Potential Biomarker for Inflammation},
 volume = {40},
 year = {2008}
}