title: Development of a simultaneous optical/PET imaging system for awake mice.
abstract: Simultaneous measurements of multiple physiological parameters are essential for the study of brain disease mechanisms and the development of suitable therapies to treat them. In this study, we developed a measurement system for simultaneous optical imaging and PET for awake mice. The key elements of this system are the OpenPET, optical imaging and fixation apparatus for an awake mouse. The OpenPET is our original open-type PET geometry, which can be used in combination with another device because of the easily accessible open space of the former. A small prototype of the axial shift single-ring OpenPET was used. The objective lens for optical imaging with a mounted charge-coupled device camera was placed inside the open space of the AS-SROP. Our original fixation apparatus to hold an awake mouse was also applied. As a first application of this system, simultaneous measurements of cerebral blood flow (CBF) by laser speckle imaging (LSI) and [(11)C]raclopride-PET were performed under control and 5% CO2 inhalation (hypercapnia) conditions. Our system successfully obtained the CBF and [(11)C]raclopride radioactivity concentration simultaneously. Accumulation of [(11)C]raclopride was observed in the striatum where the density of dopamine D2 receptors is high. LSI measurements could be stably performed for more than 60 minutes. Increased CBF induced by hypercapnia was observed while CBF under the control condition was stable. We concluded that our imaging system should be useful for investigating the mechanisms of brain diseases in awake animal models.
authors: Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors: Hiroyuki
authors: H
authors: Takuwa
authors: Yoko
authors: Y
authors: Ikoma
authors: Eiji
authors: E
authors: Yoshida
authors: Hideaki
authors: H
authors: Tashima
authors: Hidekatsu
authors: H
authors: Wakizaka
authors: Tetsuya
authors: T
authors: Shinaji
authors: Taiga
authors: T
authors: Yamaya
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D051379:Mice; D064847:Multimodal Imaging / Q000295:instrumentation / Q000379:methods*; D055096:Optical Devices; D061848:Optical Imaging / Q000295:instrumentation / Q000379:methods*; D049268:Positron-Emission Tomography / Q000295:instrumentation / Q000379:methods*; D020891:Raclopride; D019275:Radiopharmaceuticals; D014851:Wakefulness
chemical_list: D019275:Radiopharmaceuticals; D020891:Raclopride