technetium (99mtc) votumumab technetium (99mtc) votumumab technetium (99mtc) votumumab (trade name humaspect) is a human monoclonal antibody labelled with the radionuclide technetium-99m. it was developed for the detection of colorectal tumors, but has never been marketed. technetium (99mtc) votumumabmonoclonal antibodytypewhole antibodysourcehumantargettumor antigen ctaa16.88clinical dataatc codev09ia04 (who) legal statuslegal status not marketed identifierscas number148189-70-2 nchemspidernoneunii63635d7sgf ny (what is this?) (verify) the target of votumumab is ctaa16.88, a complex of cytokeratin polypeptides in the molecular weight range of 35 to 43 kda, which is expressed in colorectal tumors.