Bone marrow transplantation, a procedure where physicians exchange bone marrow that is diseased (or damaged) with healthy bone marrow. The bone tissue marrow is changed can be deliberately destroyed by high amounts of chemotherapy and/or radiation therapy. The replacement marrow may come from someone, or it may be the in-patient's very own marrow (that was removed and kept before treatment). Whenever marrow from an unrelated donor is employed, the process is an allogeneic bone marrow transplantation. If marrow is from the identical twin, it really is termed syngeneic. Autologous bone marrow transplantation utilizes the individual's own marrow.