I. To determine the maximum tolerated dose of radiation delivered via 131I-BC8 antibody (iodine I 131 monoclonal antibody BC8) when combined with the non-myeloablative regimen of fludarabine (fludarabine phosphate), 2 Gy total-body irradiation (TBI) + cyclosporine (CSP)/mycophenolate (MMF) in elderly patients with advanced acute myeloid leukemia (AML) or high risk myelodysplastic syndromes (MDS).