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

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 ¹⁸F-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 with ¹⁸F-FDG. To optimize labeling efficiency, the effects of glucose deprivation time and incubation (labeling) time with ¹⁸F-FDG were investigated. Post-labeling stability was assessed by calculating the release fraction of radioactivity and identifying the chemical forms of ¹⁸F in the released and intracellular components of ¹⁸F-FDG-labeled RBCs incubated in plasma. Just after intravenous injection of the optimized autologous ¹⁸F-FDG-labeled RBCs, dynamic PET scans were performed to evaluate in vivo imaging in normal rats and intraabdominal bleeding models (temporary and persistent bleeding).

The optimal durations of glucose deprivation and incubation (labeling) with ¹⁸F-FDG were 60 and 30 min, respectively. As low as 10% of ¹⁸F was released as the form of ¹⁸F-FDG from ¹⁸F-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.

RBCs can be effectively labeled with ¹⁸F-FDG and used for blood-pool imaging with PET in rats.