title: 18F-FDG-labeled red blood cell PET for blood-pool imaging: preclinical evaluation in rats.
abstract: BACKGROUND
  Red blood cells (RBCs) labeled with single-photon emitters have been clinically used for blood-pool imaging. Although some PET tracers have been introduced for blood-pool imaging, they have not yet been widely used. The present study investigated the feasibility of labeling RBCs with18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) for blood-pool imaging with PET. RBCs isolated from venous blood of rats were washed with glucose-free phosphate-buffered saline and labeled with18F-FDG. To optimize labeling efficiency, the effects of glucose deprivation time and incubation (labeling) time with18F-FDG were investigated. Post-labeling stability was assessed by calculating the release fraction of radioactivity and identifying the chemical forms of18F in the released and intracellular components of18F-FDG-labeled RBCs incubated in plasma. Just after intravenous injection of the optimized autologous18F-FDG-labeled RBCs, dynamic PET scans were performed to evaluate in vivo imaging in normal rats and intraabdominal bleeding models (temporary and persistent bleeding).
  
  
  RESULTS
  The optimal durations of glucose deprivation and incubation (labeling) with18F-FDG were 60 and 30 min, respectively. As low as 10% of18F was released as the form of18F-FDG from18F-FDG-labeled RBCs after a 60-min incubation. Dynamic PET images of normal rats showed strong persistence in the cardiovascular system for at least 120 min. In the intraabdominal bleeding models,18F-FDG-labeled RBC PET visualized the extravascular blood clearly and revealed the dynamic changes of the extravascular radioactivity in the temporary and persistent bleeding.
  
  
  CONCLUSIONS
  RBCs can be effectively labeled with18F-FDG and used for blood-pool imaging with PET in rats.
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
authors.forename: Yohji
authors.initials: Y
authors.lastname: Matsusaka
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. nakahara@rad.med.keio.ac.jp.
authors.forename: Tadaki
authors.initials: T
authors.lastname: Nakahara
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Iwabuchi
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan.
authors.forename: Chiyoko
authors.initials: C
authors.lastname: Nishime
authors.affiliation: Department of Biology, Keio University School of Medicine, Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kajimura
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Jinzaki
keywords: 18F-FDG; Blood-pool imaging; Intraabdominal bleeding; PET; Red blood cell