Bifunctional antibody for imaging human tumors; prepared by cross-linking Fab′ fragments of ZCE025, which binds carcinoembryonic antigen (CEA), and CHA255, which binds benzyl-EDTA(indium) chelates such as 111In-EOTUBE [ii]. In practice, the bifunctional antibody is injected and allowed to localize in the target as ZCE025 binds to CEA, and then the 111In chelate is injected and captured by the pretargeted CHA255. Uncaptured 111In chelate is efficiently eliminated via the kidneys, leaving little background signal in normal tissue.