- Group 8 (pediatric patients only)*: Patients undergo TBI twice a day on days -7 to -5. Patients also receive etoposide IV over 24 hours on day -4 and cyclophosphamide IV over 1 hour on days -3 and -2. On day 0, patients undergo SCT. Beginning on day 7, patients may receive G-CSF IV once daily until blood counts recover.