(... ZEH-vuh-lin) A radiolabeled monoclonal antibody used to find certain types of B-cell non-Hodgkin lymphoma. It is also being studied in the diagnosis of other types of B-cell tumors. 111In-Zevalin is made up of the monoclonal antibody ibritumomab plus the radioisotope indium In 111. It binds to a protein called CD20, which is found on B cells. A machine is used to find which cells in the body have taken up 111In-Zevalin. 111In-Zevalin is a type of radioimmunoconjugate. Also called 111In-ibritumomab tiuxetan and indium In 111-ibritumomab tiuxetan.