Imaging T cell migration and targeting. (a) Sequential oblique projections of summed coronal MicroPET images of a mouse bearing autologous Epstein-Barr virus–transformed B-cell lines (BLCL) (tumor 1), HLA-A0201–matched BLCL (tumor 2), HLA-mismatched BLCL (tumor 3), and HLA-A0201 ALL (tumor 4) tumors located in the left and right shoulders and the left and right thighs, respectively. All images are from a single representative animal at a 45° angle from the prone position to visualize the spleen, and all images were obtained 4 hours after [¹²⁴I]FIAU injection on days 1, 8, and 15 after T cell infusion. K, kidneys; H, heart; St, stomach; Sp, spleen; Bl, bladder. (b) Graph of radioactivity levels (percent dose/g) that localized in different tumors and tissues, at three time points (2, 9, and 16 days) after EBV-specific TKGFP-CTL administration. Radioactivity was measured 24 hours after [¹²⁴I]FIAU injection. Adapted with permission from ref. 57.