Patients who are not candidates for tandem transplant may receive melphalan plus total body irradiation (TBI). Melphalan is administered IV on day -4. Total body irradiation is administered three times a day on days -3 and -2 and twice on day -1. At least 4 hours must elapse between each treatment. Hematopoietic stem cells are reinfused on day -1 upon completion of TBI or on day 0.