Hematopoetic Stem Cell Transplantation (HSCT) is the only potentially curative treatment for patients resistant to chemotherapy and external radiation treatments in a number of indications including AML, Acute Lymphoblastic Leukemia (ALL), Hodgkin Lymphoma, Non-Hodgkin Lymphoma, Multiple Myeloma, etc., as well as in some non-malignant diseases.  Prior to bone marrow transplantation, in most cases it is essential to ablate the existing bone marrow.  Bone marrow ablation is usually performed using a combination of chemotherapy and total body irradiation, both of which cause severe and potentially lethal side effects.  Many patients are not considered for this therapy due to their advanced age, generally poor condition and/or comorbidities, all of which make them ineligible for high dose chemotherapy and total body irradiation.