Intensity Modulated Total Marrow Irradiation in Fully Human Leukocyte Antigen (HLA)-Matched and Partially-HLA Mismatched Allogeneic Transplantation Patients With High-Risk Acute Myeloid Leukemia (AML), Chronic Myeloid Leukemia (CML), and Myelodysplastic Syndrome (MDS)

This study is testing a newer form of full-body radiation (called intensity-modulated total marrow irradiation, or IMTMI) combined with chemotherapy as a preparation for bone marrow transplant in patients with high-risk leukemia (AML, CML) or myelodysplastic syndrome (MDS) — with the goal of reducing side effects compared to older radiation methods. **You may be eligible if...** - You are between 18 and 65 years old - You have high-risk AML, CML, or MDS — including cases that relapsed, are in remission 2 (CR2), or have poor-risk genetic features - You have a matched or partially-matched bone marrow donor - You are in adequate health to undergo transplant **You may NOT be eligible if...** - Your cancer is in active relapse with no response to treatment - You have significant heart, lung, or liver disease - You have received prior bone marrow transplant - You are pregnant Talk to your doctor to see if this trial is right for you.