DiR allows sensitive NIR whole-body imaging tracking of human leukemic cells and analysis of their homing in immunocompromised recipients. HL60 cells (10⁷) stained with 20μM DiR (HL60-DiR) were injected in 4 animals, whereas 2 controls were injected with unlabeled cells. At 24 hours after injection, 1 control and 2 animals injected with HL60-DiR were killed and prepared for whole-body imaging. Frontal acquisition (top left panel) and dorsal acquisition (top right panel) are displayed. The same operations have been realized 13 days after the injection (lower panels). The intensity settings for the acquisition and the processing of the images are identical for the 4 images. Fluorescence intensity scale is displayed on the right side of the images. J indicates jaws; St, sternum; E, elbow; L, liver; W, wrist; LN, lymph node; K, knee; F, foot; C, calvaria; S, scapula; Sc, spinal column; and Sp, Spleen.