The purpose of this study is to estimate the radiation absorbed dose to the bone marrow and kidneys based on whole-body gamma camera image data for comparison with that obtained using mathematical models based on whole body counting from a small gamma detection device called a thyroid probe; to obtain pharmacokinetic data following administration of 166Ho-DOTMP; and to evaluate safety and efficacy in patients who receive 25 Gy targeted therapy of 166Ho-DOTMP and 200 mg/m2 melphalan followed by autologous peripheral blood stem cell transplant (PBSCT).