@misc{oai:repo.qst.go.jp:00069780,
 author = {Kimura, Yuichi and Naganawa, Mika and Mishina, Masahiro and Sakata, Muneyuki and Oda, Keiichi and Ishii, Kenji and Ishiwata, Kiichi and 木村 裕一 and 長縄 美香 and 坂田 宗之 and 織田 圭一 and 石井 賢二 and 石渡 喜一},
 month = {Jul},
 note = {Objectives: [11C]MPDX is a clinically available radioligand for quantification of the adenosine A1 receptor (A1R) [1], and its kinetic analysis was reported in [2]. The purpose of this study was to investigate an applicability of simplified graphical algorithms for human studies based on ROI analysis.
\nMethods: Six normal subjects were included in this study. The dose was 610+/-126 MBq, and the specific activity was 53+/-37 MBq/nmol. Dynamic PET scans were performed for 1 hour using SET-2400W (Shimadzu, Kyoto, Japan) in two-dimensional mode with arterial blood sampling. A total of 24 ROIs was placed manually on the summed images: cerebellum (reference), pons, midbrain, caudate, putamen, thalamus, posterior cingulate, and frontal, temporal, occipital, and parietal lobes. The ROI-averaged tissue time activity curves (tTACs) were analyzed using five algorithms: one- and two-tissue compartment models (1T and 2T), Logan graphical analysis (LGA), and a reference LGA with or without a clearance rate of a reference region (k2) (LGAR-k2 and LGARNok2)[3]. For LGAR-k2, the k2 in a reference region was derived from the cerebellum using 1T. All graphical analyses were applied after 20-minute post-injection.
\nResults: The metabolism of [11C]MPDX was slow; the parent fraction was 0.74+-0.07 at 60 min after injection. The tTACs were well described using 2T with a constraint of VND that was estimated from the reference region using 1T. The values of VT and K1 ranged from 0.52+-0.11 (cerebellum) to 0.72+-0.13 mL/cm3 (posterior putamen) and from 0.10+-0.03 (cerebellum) to 0.13+-0.04 mL/min/cm3 (posterior putamen), respectively. The k2 in reference regions were (0.45+-0.11 min-1). The kinetics in reference regions was described using 1T model, and 2T fitting could not give us reasonable VND, VND(1T)=0.98*VND(LGA)-0.06 (r2=0.96). In the graphical analyses, BPND using the simplified algorithms of LGAR-k2 and LGAR-Nok2 matched well with those using LGA: BPND(LGAR-k2)= 0.99*BPND(LGA)+0.01 (r2=0.95) and BPND(LGAR-Nok2)= 0.96*BPND(LGA)-0.01(r2=0.94).
\nConclusions: Both the simplified algorithms based on Logan graphical analysis without an arterial input function provided corresponding BPND with those of LGA using an input function in ROI-based analysis. These results implied that LGAR-Nok2 was applicable for the quantification of A1Rs using [11C]MPDX.
\nReferences:
[1] Ishiwata, et al., Ann Nucl Med, 16, 377-382, 2002.
[2] Y Kimura, et al., Nucl Med Biol, 31, 975-981, 2004.
[3] J Logan, et al., J Cereb Blood Flow Metabo, 16, 834-840, 1996.
Acknowledgement: This work was supported by Grants-in-Aid for Scientific Research (B) No. 20390333,(B) 20390334 and (B) No. 16390348., Brain'09 & BrainPET'09},
 title = {Simplified Quantification of Adenosine A1 Receptor with [11C]MPDX and Graphical Analysis},
 year = {2009}
}