BMT-06: Study of Intensity Modulated Total Marrow Irradiation (IM-TMI)

Experimental: Total marrow irradiation 1.5 Gray (Gy) twice a daily on days -3 and -2

"All patients will receive the following standard conditioning regimen:~Fludarabine 30 mg/m2 IVPB daily from Day -6 (6 days before stem cell infusion) through Day -2"

IV cyclophosphamide 14.5 mg/kg intravenously prior to transplant on Days -6 and -5.

Total body irradiation 2Gy on day -1.

Stem cell infusion on day 0.

Tacrolimus IV initially in doses of 0.15 mg/kg/day for 3 days, followed by conversion to oral therapy (0.15 mg/kg twice daily)

Cyclophosphamide on days 3 and 4 after transplant at a dose of 50mg/kg per day