CXCR4 and neoplasm: A biodistribution study revealed that 211At-CXCR4 mAb as well as 125I-CXCR4 mAb showed the highest tumor uptake and the highest tumor-to-muscle ratio at 6 h, which agreed with the physical half-life of 211At, although the precise biological behavior from 6 to 24 h was not evaluated in this study.