Before receiving Emma's bone marrow, Katie underwent radiotherapy - known as
total body radiation - and the most powerful form of chemotherapy, which has left her reeling.
Nathan told the congressional panel that he was first given three days of
total body radiation and three days of intense chemotherapy before the transplant "to completely kill my own leukemia-producing marrow.
City of Hope scientists also are investigating using radioimmunotherapy instead of
total body radiation in which engineered immune molecules deliver targeted radiation directly to cancer cells in the transplant patient.