title: Novel system using microliter order sample volume for measuring arterial radioactivity concentrations in whole blood and plasma for mouse PET dynamic study.
abstract: This study aimed to develop a new system, named CD-Well, for mouse PET dynamic study. CD-Well allows the determination of time-activity curves (TACs) for arterial whole blood and plasma using 2-3 µL of blood per sample; the minute sample size is ideal for studies in small animals. The system has the following merits: (1) measures volume and radioactivity of whole blood and plasma separately; (2) allows measurements at 10 s intervals to capture initial rapid changes in the TAC; and (3) is compact and easy to handle, minimizes blood loss from sampling, and delay and dispersion of the TAC. CD-Well has 36 U-shaped channels. A drop of blood is sampled into the opening of the channel and stored there. After serial sampling is completed, CD-Well is centrifuged and scanned using a flatbed scanner to define the regions of plasma and blood cells. The length measured is converted to volume because the channels have a precise and uniform cross section. Then, CD-Well is exposed to an imaging plate to measure radioactivity. Finally, radioactivity concentrations are computed. We evaluated the performance of CD-Well in in vitro measurement and in vivo (18)F-fluorodeoxyglucose and [(11)C]2-carbomethoxy-3β-(4-fluorophenyl) tropane studies. In in vitro evaluation, per cent differences (mean±SE) from manual measurement were 4.4±3.6% for whole blood and 4.0±3.5% for plasma across the typical range of radioactivity measured in mouse dynamic study. In in vivo studies, reasonable TACs were obtained. The peaks were captured well, and the time courses coincided well with the TAC derived from PET imaging of the heart chamber. The total blood loss was less than 200 µL, which had no physiological effect on the mice. CD-Well demonstrates satisfactory performance, and is useful for mouse PET dynamic study.
authors.affiliation: Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan. Faculty of Biology-Oriented Science and Technology, Department of Computational Systems Biology, Kinki University, Kinokawa, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kimura
authors.forename: Chie
authors.initials: C
authors.lastname: Seki
authors.forename: Nobuya
authors.initials: N
authors.lastname: Hashizume
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamada
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Wakizaka
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nishimoto
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hatano
authors.forename: Keishi
authors.initials: K
authors.lastname: Kitamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Toyama
authors.forename: Iwao
authors.initials: I
authors.lastname: Kanno
mesh_terms: D000818:Animals; D001158:Arteries / Q000000981:diagnostic imaging*; D057230:Limit of Detection; D008297:Male; D051379:Mice; D010949:Plasma / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D011851:Radioactivity; D051381:Rats; D013997:Time Factors