@article{oai:repo.qst.go.jp:00081802,
 author = {Manabu, Kubota and Chie, Seki and Yasuyuki, Kimura and Keisuke, Takahata and Hitoshi, Shimada and Yuhei, Takado and Kiwamu, Matsuoka and Kenji, Tagai and Yasunori, Sano and Yamamoto, Yasuharu and Maki, Okada and Tatsuya, Kikuchi and Masanori, Ichise and Kazunori, Kawamura and Zhang, Ming-Rong and Makoto, Higuchi and Manabu, Kubota and Chie, Seki and Yasuyuki, Kimura and Keisuke, Takahata and Hitoshi, Shimada and Yuhei, Takado and Kiwamu, Matsuoka and Kenji, Tagai and Yasunori, Sano and Yamamoto, Yasuharu and Maki, Okada and Tatsuya, Kikuchi and Masanori, Ichise and Kazunori, Kawamura and Zhang, Ming-Rong and Makoto, Higuchi},
 issue = {9},
 journal = {European Journal of Nuclear Medicine and Molecular Imaging},
 month = {Feb},
 note = {Purpose: 
Phosphodiesterase 7 (PDE7) is an enzyme that selectively hydrolyses cyclic adenosine monophosphate, and its dysfunction is implicated in neuropsychiatric diseases. However, in vivo visualization of PDE7 in human brains has hitherto not been possible. Using the novel PET ligand 11C-MTP38, which we recently developed, we aimed to image and quantify PDE7 in living human brains. 
Methods: 
Seven healthy males underwent a 90-min PET scan after injection of 11C-MTP38. We performed arterial blood sampling and metabolite analysis of plasma in six subjects to obtain a metabolite-corrected input function. Regional total distribution volumes (VT’s) were estimated using compartment models, and Logan plot and Ichise multilinear analysis (MA1). We further quantified the specific radioligand binding using the original multilinear reference tissue model (MRTMO) and standardized uptake value ratio (SUVR) method with the cerebellar cortex as reference. 
Results: 
PET images with 11C-MTP38 showed relatively high retentions in several brain regions, including in the striatum, globus pallidus, and thalamus, as well as fast washout from the cerebellar cortex, in agreement with the known distribution of PDE7. VT values were robustly estimated by two-tissue compartment model analysis (mean VT = 4.2 for the pallidum), Logan plot, and MA1, all in excellent agreement with each other, suggesting the reversibility of 11C-MTP38 binding. Furthermore, there were good agreements between binding values estimated by indirect method and those estimated by both MRTMO and SUVR, indicating that these methods could be useful for reliable quantification of PDE7. Because MRTMO and SUVR do not require arterial blood sampling, they are the most practical for the clinical use of 11C-MTP38-PET. Conclusion: 
We have provided the first demonstration of PET visualization of PDE7 in human},
 pages = {2846--2855},
 title = {A First-in-human Study of 11C-MTP38, a Novel PET Ligand for Phosphodiesterase 7},
 volume = {48},
 year = {2021}
}