(18)F-FDG-labeled red blood cell PET for blood-pool imaging: preclinical evaluation in rats

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 with (18)F-2-deoxy-2-fluoro-D-glucose ((18)F-FDG) for blood-pool imaging with PET. RBCs isolated from venous blood of rats were washed with glucose-free phosphate-buffered saline and labeled with (18)F-FDG. To optimize labeling efficiency, the effects of glucose deprivation time and incubation (labeling) time with (18)F-FDG were investigated. Post-labeling stability was assessed by calculating the release fraction of radioactivity and identifying the chemical forms of (18)F in the released and intracellular components of (18)F-FDG-labeled RBCs incubated in plasma. Just after intravenous injection of the optimized autologous (18)F-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) with (18)F-FDG were 60 and 30 min, respectively. As low as 10% of (18)F was released as the form of (18)F-FDG from (18)F-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, (18)F-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 with (18)F-FDG and used for blood-pool imaging with PET in rats. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13550-017-0266-3) contains supplementary material, which is available to authorized users.