Intensive conditioning regimens used in allogeneic hematopoietic cell transplant (HCT) help to eliminate hematologic tumors and reduce the risk of relapse, but are also characterized by high toxicity. Total marrow and lymphoid irradiation (TMLI) is a specialized radiation technique that specifically targets marrow and lymphoid tissue to maximize antitumor efficacy while reducing off target toxicity. Despite these benefits, TMLI is technically challenging and time consuming. The radiation oncology team at Stanford has developed an automated TMLI platform to overcome these challenges. In this phase II trial, automation will be incorporated into a previously validated conditioning regimen of fludarabine/cyclophosphamide/TMLI HCT with post-transplant cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis to confirm the feasibility and safety of automation in patients receiving allogeneic HCT for high-risk myeloid malignancies.