@article{oai:repo.qst.go.jp:00046267,
 author = {Sato, Koichi and Fukushi, Kiyoshi and Shinoto, Hitoshi and Shimada, Hitoshi and Tanaka, Noriko and Hirano, Shigeki and Irie, Toshiaki and 佐藤 康一 and 福士 清 and 篠遠 仁 and 島田 斉 and 田中 典子 and 平野 成樹 and 入江 俊章},
 issue = {4},
 journal = {NeuroImage},
 month = {Nov},
 note = {Long dynamic scans (60-120min) are often required for estimating the k(3) value, an index of receptor density, by positron emission tomography (PET). However, the precision of k(3) is usually low in kinetic analyses for reversible PET ligands compared with irreversible ligands. That is largely due to unstable estimation of the dissociation rate constant, k(4). We propose a novel '3P+' method for estimating k(3) of moderately reversible ligands, where a 3-parameter model without k(4) is applied to early-phase PET data to obtain a good model-fit of k(3) estimation. By using [(11)C] Pittsburgh compound B (PIB) (k(4)=0.018/min) as an example of a moderately reversible ligand, the 3P+ method simulation with a 28min PET scan yielded less than 3% k(3) relative bias with a +100% k(3) change. In [(11)C]PIB PET scans of 15 normal controls (NC) and nine patients with Alzheimer's disease (AD), the 3P+ method provided a precise k(3) estimate (mean SE of 13.6% in parietal cortex; covariance matrix method). The results revealed linear correlations (r=0.964) of parietal k(3) values in 24 subjects between 28minute 3P+ method and conventional 90minute 4-parameter method. A good separation of k(3) between NC and AD groups (P<0.001; t-test) was replicated in 28minute 3P+ method. The short-scan 3P+ method may be a practical alternative method for analyzing reversible ligands.},
 pages = {3149--3158},
 title = {A short-scan method for k(3) estimation with moderately reversible PET ligands: Application of irreversible model to early-phase PET data.},
 volume = {59},
 year = {2011}
}