In summary, analyses of the pharmacokinetics and dosimetry of 211At-CXCR4 mAb in the tumor xenograft revealed that the clearance from blood and the tumor uptake matched the physical half-life of 211At, and the target cell-to-normal organ ratios of absorbed dose would be high enough to eradicate tumor cells, although tumor uptake was relatively low. The gene discussed is CXCR4; the disease is neoplasm.