BEAM chemotherapy is the standard treatment for lymphoma. BEAM is a combination of chemotherapy drugs (carmustine, cytarabine, etoposide, and melphalan). Rituximab is an antibody made from human and mouse proteins. It reacts with a certain molecule on the surface of lymphoma cells and helps the body's immune system destroy the lymphoma cells. 90Y Zevalin is also an antibody made from mouse proteins. However, it has a particle of radiation attached to it. 90Y Zevalin works by attaching to lymphoma cells, and the radiation particle destroys the lymphoma cell.