Figure 2.

This figure depicts the ex vivo labelling process for absolute labeled cell quantification. During the cell-labelling phase, cells are first incubated with a ¹⁹F-based agent for up to 48 hours in order for ¹⁹F spins to become internalized within cells. Labeled cells are then utilized in three different processes. Process 1 demonstrates the performing of NMR on a small sample of these labeled cells to obtain their fractional fluorine content (Fc). Process 2 involves conventional ¹H imaging of animals and human beings post injection to provide the underlying anatomy. Process 3 involves ¹⁹F imaging of animals and human beings to provide signals from both a reference phantom of known concentration and signals from the injected cells. The signals from these images, combined with Fc, allow for quantification of injected cells.