Recently, Sriraman et al. shared the results of their pioneering research on 18F-labeled anti-human CD8 VHH (small antibody against human CD8) in mice with leukaemia cell line xenografts, which enabled the acquisition of high-quality immuno-PET imaging one hour after the radiopharmaceutical intravenous injection, in contrast to 89Zr-labelled tracers which have an optimal imaging quality several days after injection only [103]. The gene discussed is CD8A; the disease is leukemia.