 - To determine the efficacy of high-dose melphalan 200mgm2 in combination with targeted radiotherapy delivered by yttrium Y 90 anti-CD66 monoclonal antibody BW250183, in terms of disease response complete remission rate and change in serum free light chain level before and after treatment with yttrium Y 90 anti-CD66 monoclonal antibody BW250183, in patients undergoing autologous hematopoietic stem cell transplantation for multiple myeloma. 